Subscriber access provided by BOSTON UNIV
Article
Investigating the potential of ion mobility-mass spectrometry for microalgae biomass characterization Maíra Fasciotti, Gustavo H. M. F. Souza, Giuseppe Astarita, Ingrid Chastinet Ribeiro Costa, Thays V. C. Monteiro, Claudia M. L. L. Teixeira, Marcos Nogueira Eberlin, and Amarijt Singh Sarpal Anal. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.analchem.9b02172 • Publication Date (Web): 31 May 2019 Downloaded from http://pubs.acs.org on June 3, 2019
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
1
Analytical Chemistry
2
Article
3
Title: “Investigating the potential of ion mobility-mass spectrometry for microalgae
4
biomass characterization”
5
Authors: Maíra Fasciotti1,5*, Gustavo H. M. F. Souza2, Giuseppe Astarita3, Ingrid C.
6
R. Costa1, Thays. V. C. Monteiro1, Claudia M. L. L. Teixeira4, Marcos N. Eberlin5,6,
7
Amarijt S. Sarpal1
8
1
9
Chemical Metrology, Laboratory of organic analysis, 25250-020, Duque de Caxias, RJ,
National Institute of Metrology, Quality and Technology (INMETRO), Division of
10
Brazil
11
2
MS Applications & Development Laboratory, Waters Corporation, Barueri, SP, Brazil;
12
3
Department of Biochemistry and Molecular & Cellular Biology, Georgetown
13
University, Washington, DC, USA;
14
4 Instituto
15
5
16
Campinas – UNICAMP, Campinas, SP, Brazil.
17
6
18
Brazil
19
*corresponding author: M. Fasciotti,
[email protected] Nacional de Tecnologia (INT), Rio de Janeiro, Rio de Janeiro, Brazil;
ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of
Mackenzie Presbyterian University, School of Engineering, 01302-907 São Paulo, SP
20 21 1 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 2 of 41
1
ABSTRACT
2
Algae biomass is formed by an extremely complex set of metabolites and its molecular
3
characterization has been very challenging. We report the characterization of
4
microalgae extracts via traveling wave ion mobility – mass spectrometry (TWIM-MS)
5
by two different analysis strategies. First, the extracts were analyzed by direct infusion
6
electrospray ionization (ESI) with no previous chromatographic separation (DI-ESI-
7
TWIM-MS). Second, the samples were screened for metabolites and lipids using an
8
untargeted high throughput method that employs ultra-high performance liquid
9
chromatography (UHPLC) using data independent analysis (DIA) – MSE (UHPLC-
10
HDMSE). Sixteen different microalgae biomasses were evaluated by both strategies.
11
DI-ESI-TWIM-MS was able, via distinct drift times, to set apart different classes of
12
metabolites, with the differences in the profiles of each microalga readily evident. With
13
the UHPLC-HDMSE approach, 1251 different compounds were putatively annotated
14
across 16 samples with 210 classified as lipids. From the normalized abundance for
15
each annotated compound category, a detailed profiling in terms of metabolites, lipids,
16
and lipid classes of each sample was performed. The reported workflow represents a
17
powerful tool to determine the most suitable biotechnological applications for a given
18
alga type, and may allow for real-time monitoring of the algae composition distribution
19
as function of growth conditions, feedstocks, and the like. The determination of collision
20
cross section results in improved confidence in the identification of triacylglycerols in
21
samples, highly applicable to biofuels production. The two analysis strategies explored
22
in this work offer powerful tools for the biomass industry by aiding in the identification
23
of ideal strains and culture conditions for a specific application, saving analysis time,
24
and facilitating identification of large number of constituents at once.
2 ACS Paragon Plus Environment
Page 3 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
1
INTRODUCTION
2
Algae are a diverse group of predominantly aquatic organisms that efficiently
3
perform photosynthesis. They are responsible for close to 90% of the photosynthesis
4
performed on the planet 1,2,3 and form a diversified polyphyletic group; that is, they in
5
fact form a group of an expanded set of organisms belonging to different phylogenetic
6
groups.4 Algae have been widely studied for decades within several fields of science.
7
With the advent of modern biotechnology, algae have received even more attention,
8
especially with the emergence of third- and fourth-generation fuels. 5,6,7 After it was
9
realized that algae were able to provide better yields than processes with other
10
biomasses, biofuels from algae have been framed as more promising 3rd-generation
11
fuels.8 Intensive research followed in the quest of more efficient production of different
12
types of biofuels and chemicals from algae. 9, 10 A very interesting advantage of algae
13
as source of biomass is that they can be grown in waste and salty waters,11,12 acting
14
simultaneously as a bioremediation strategy.13,14
15
Currently, studies are focused on producing biohydrogen from algae via solar 15
energy and water,
17
bioethanol.
18
algae bioprocesses.
19
produced via algae, since some oleaginous algae have 30-60% (w/w) of
20
triacylglycerols on a dry basis.20,21 To obtain better yields to produce biodiesel
21
precursor lipids – mainly triacylglycerols – the algae species have been cultivated in
22
different culture media, which strongly influence biomass composition. 22 For instance,
23
nitrogen limitation or nutrient imbalance increase lipid content in the microalgae cells,
24
leading to high biodiesel potential production.
17
as well as bioisoprene (2-methyl-1,3-butadiene)
16
16
and
Butanol and isobutanol have also been directly produced from CO2 via 18,19
Biodiesel is perhaps the most promising biofuel to be
23
Algae-based biofuels are indeed
3 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 4 of 41
1
promising, hence major improvements in algae technology are being tested, especially
2
for downstream and upstream processes optimization. 24, 25
3
The characterization of the resulting algae biomass is also extremely important
4
to ensure that the growth conditions are actually affecting the biomass composition as
5
desired,26 and can guide best biotechnological practices in the production of biofuels,
6
biogas, bio-based chemicals, bioremediation or even in the area of nutraceutical and
7
food supplements. 27, 28
8
The characterization of this extremely complex
29
algae biomass has been
9
performed using several analytical techniques, from the less expensive but less
10
comprehensive classical physical-chemical methods such as elemental analysis,
11
gravimetric determination of total lipid content or classical methods for total protein or
12
carbohydrate measurements,
13
consuming instrumental techniques such as NMR
14
techniques 34 and chromatography. 35, 36
30
to more complex but more training and time31,32,
FTIR,
33
laser-based
15
Mass spectrometry (MS) generally coupled to previous chromatographic
16
separation has been established as a powerful and versatile analytical technique for
17
both quantitation of target compounds as well as identification of a massive number of
18
unknown compounds at once in a wide variety of matrices and samples. MS-based
19
analytical methods have already been successfully applied for algae characterization,
20
and a great variety of chemicals have been identified such as peptides,37 proteins,38
21
toxins,39 isoflavones,
22
hydrocarbons,45 aldehydes,46 and others. 47, 48, 49
40
lipids,
41
fatty acids,42 sterols,43 polysaccharides44
23
With the introduction of commercially available instruments, ion mobility coupled
24
with high resolution mass spectrometry (IM-HRMS), has recently become the
25
technique of choice in omics sciences, especially in proteomics, lipidomics and 4 ACS Paragon Plus Environment
Page 5 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
50,51, 52, 53, 54
1
metabolomics studies.
The technique is frequently coupled with liquid
2
chromatography leading to multidimensional data, combining the compounds'
3
parameters of retention times versus ions m/z ratios versus ions drift times, the former
4
being achieved in a few minutes and the latter on the millisecond timescale.
5
Ion mobility (IM) is a technique that separates gaseous ions while traveling
6
through a buffer gas under the influence of an electrical field. 55,56 TWIM separation is
7
based on shape/size of the ions as measured by their collision cross section (CCS),
8
ion-dipole interactions of the ions with the neutral drift gas molecules.57
9
Previous studies have demonstrated the excellent performance of the IM
10
technique for isomers and isobars separation and characterization of complex
11
mixtures,58,59,60,61 as well as for increasing the selectivity of lipidomics and
12
metabolomics analyses.
13
separated forming sets of characteristic tendencies, that is, drift time regions.
50
In complex mixtures, different classes of compounds are
14
To determine the best application for a specific biomass, and also to evaluate
15
the process of algae production, a simple, fast but as comprehensive as possible
16
molecular characterization, for instance of TAGs for biodiesel production would be of
17
great help. This work aimed therefore to explore the potential of ion mobility coupled
18
to high resolution mass spectrometry to comprehensively characterize different
19
microalgae biomasses. Two different TWIM-MS analysis strategies were tested as
20
detailed below: DI-ESI-TWIM-MS and UHPLC-HDMSE.
21
5 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
1
EXPERIMENTAL SECTION
2
Chemicals
Page 6 of 41
3
Methanol and chloroform (LC grade) were purchased from Tedia Brazil (Rio de
4
Janeiro, Brazil). Analytical grade phosphoric acid (85% w/w), formic acid (98−100%),
5
LC grade leucine enkephalin, poly-DL-alanine and ammonium formate were purchased
6
from Sigma-Aldrich (Merck Sigma-Aldrich, KGaA, Darmstadt, Germany). Mobile
7
phases acetonitrile and propan-2-ol (MS grade) were purchased from J. T. Backer
8
(Sao Paulo, Brazil). Water was purified using a Millipore Milli-Q system (Merck
9
Millipore, KGaA, Darmstadt, Germany).
10
Samples
11
In total, 16 microalgae biomasses were analyzed, including 5 from different
12
genera (Tetraselmis aff. chuii, Spirulina platensis, Dunaliella salina, Chlorella vulgaris,
13
Scenedesmus ecornis), and these obtained under different cultivation times and/or
14
culture media composition or light source (Scheme 1). See SI for detailed cultivation
15
conditions. For comparison with microalgae extracts, commercial samples of refined
16
soybean, corn, rapeseed, sunflower and olive oils were purchased in the local market.
6 ACS Paragon Plus Environment
Page 7 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
1 2 3 4
SCHEME 1. Sixteen different microalgae biomasses analyzed in this work. Sample preparation Lyophilized biomasses of different algae were extracted using the Bligh and 62
with some modifications.
63
5
Dyer like method
For Tetraselmis aff. chuii, Spirulina
6
platensis, Chlorella vulgaris and Scenedesmus ecornis samples, 0.1 g of each
7
lyophilized biomass was homogenized with 15 mL of chloroform:methanol:H2O
8
(2:1:0.5, v/v) and placed in an ultrasonic bath (200W, 50 Hz) for one hour at 30 °C.
9
The lipid fractions were filtered using filter paper and then dried under water vapor heat
10
set to 60 °C. The dried lipid fractions were determined gravimetrically. For the 7 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 8 of 41
1
Dunaliella salina samples (ABC and DEF culture media) the protocol was different due
2
to the high concentration of salts in the dried biomass. The lipid extraction was then
3
performed in two steps: the first consisted in the dry biomass extraction using pure
4
chloroform (20 mL) under ultrasonic agitation also for 1h at 30 °C. The solid was
5
decanted and the liquid phase was transferred to a beaker. Then, in the second step,
6
a volume of 20 mL of methanol was used with 300 µL of H2O to extract the solid residue
7
of the first step (with pure chloroform), under the same extraction conditions. The
8
chloroform and methanol extracts were also evaporated under 60 °C and the dried
9
extracts were gravimetrically determined. All the lipid extracts for all samples were then
10
re-dissolved in pure methanol at an approximate concentration of 2 mg .mL-1. Then, 20
11
µL of the lipid fraction in methanol were diluted in 1 mL of methanol with 0.1 % of formic
12
acid for the direction infusion approach and in mobile phase B for the UHPLC-HDMSE
13
analysis.
14
METHODS
15
DI-ESI-TWIM-MS approach
16
Direct infusion (DI) approach was performed on a Traveling Wave Ion Mobility
17
Mass Spectrometer (TWIM-MS, Synapt HDMS, Waters, UK). The samples were direct
18
infused at a flow rate of 20 μL/min using an external syringe pump into the ESI source
19
operated in positive mode (3.5 kV), cone and extractor cone were 40 and 5.0 V
20
respectively. The source and desolvation temperatures were 80 and 150 °C, and a
21
nitrogen nebulizer gas flow rate of 400 L/h. Parameters such as the drift gas pressure
22
(N2, 1.05 mbar), height (30 V) and wave velocity (650 m/s) were optimized to obtain
23
the same spectra as when only QTOF mode is used, avoiding any distortion or
24
sensitivity loss, in a range of m/z 50 – 1,500. The mass spectrometer was calibrated in 8 ACS Paragon Plus Environment
Page 9 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
1
ESI(+) mode at 10,000 resolution (FWHM at m/z 882.7999) over acquisition mass
2
range of m/z 50 − 2000, using a solution of phosphoric acid 0.1% (v/v) in
3
acetonitrile:H2O (1:1). The most abundant ions in the mass range from m/z 800 to 1000
4
(expected TAG region) had also their CCS values experimentally determined
5
according to the procedure described by Paglia and Astarita in Nature Protocols (2017)
6
50
7
mg/L, in H2O: acetonitrile 50:50 + 0.1% of formic acid) as reference values for
8
calculation. A spreadsheet with the CCS calculations for isobaric ions is available as
9
Supporting Information.
10
for performing the manual CCS calibration, using poly-DL-alanine oligomers (10
UHPLC-HDMS E
11
UHPLC-HDMSE was performed in a Synapt G2-Si mass spectrometer with an
12
ACQUITY™ UHPLC i-Class as chromatograph (both Waters, UK). The separation was
13
carried out using an ACQUITY CSH™ C18, 2.1 mm x 100 mm column kept at 55 ˚C
14
during analysis. Mobile phase consisted of solvent A (acetonitrile:H2O 60:40 + 10mM
15
ammonium formate + 0.1% formic acid); and solvent B (propan-2-ol:acetonitrile 90:10
16
+10 mM ammonium formate + 0.1% formic acid). The gradient elution program was as
17
follows: 0 − 0.99 min from 60:40 A:B to 57:43 A:B; 0.99 - 1.24 min from 57:43 A:B to
18
50:50 A:B; 1.24 – 5.39 min from 50:50 A:B to 1:99 A:B; 5.39 – 5.64 min from 1:99 A:B
19
to 60:40 A:B, then remaining constant until 8 min. Flow rate was 0.7 mL.min-1 and
20
sample injection volumes were 4 μL (FTN AutoSampler). Total run time was 8 min.
21
The mass spectrometer was equipped with an ESI source, also in positive ion mode,
22
operating under 3.5 kV of capillary and 40 V of cone. The source and the desolvation
23
temperature were 110 and 450 °C, respectively, and the nitrogen nebulizer gas was
24
used at flow rate of 900 L/h at a pressure of 6 bar. The mass spectrometer was 9 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 10 of 41
1
operated in ion-mobility (HDMSE) mode. In this method, the mass analyzer operates
2
in both low energy (for precursors ions) and high energy (for fragments) mode to
3
promote collision induced dissociation (CID) of non-selected precursor ions, leading to
4
spectra of product fragments aligned to the precursor ion. In this technique, the term
5
“HD” comes from "high definition", because in this case the MSE acquisition technique
6
is also coupled to the ion mobility. Trap collision energy (low) was 4 eV, and transfer
7
collision energy (high) was a ramp from 25 to 65 eV, also using argon as collision gas.
8
The IMS cell was filled with N2 under a pressure of 3.65 mbar. The IM cell was also
9
calibrated using poly-DL-alanine (10 mg/L) in H2O: acetonitrile (50:50 + 0.1% of formic
10
acid) to allow the calculation of the analytes CCS values. Both MS calibration and lock
11
mass correction during analysis was performed using a leucine enkephalin (theoretical
12
m/z 554.2620) solution in H2O:acetonitrile (50:50 + 0.1% formic acid) at a
13
concentration of 100 pg/μL and infused at a flow rate of 0.010 mL/min. The acquisitions
14
in HDMSE mode ranged from m/z 50 to 1500. Default IMS conditions were used for
15
IMS screening (T-wave velocity ramp start of 1000 m/s and end of 300 m/s; and T-
16
wave pulse height of 40 V).
17
Data processing and statistics
18
Both DI-ESI-TWIM-MS and UHPLC-HDMSE data were collected using the
19
software MassLynx 4.1v (SCN 639 for Synapt HDMS and SCN 932 for Synapt G2-Si,
20
Waters, UK). The DI-ESI-TWIM-MS spectral data were evaluated using the software
21
DriftScope 2.7v and HDMS Compare 1.0v. The chemometric analysis for samples
22
statistical comparison after data preprocessing (spectra normalization by height and
23
Pareto scaling – default software parameters) was performed using the software
24
EZinfo 2.0v (Umetrics, USA) appended into MarkerLynx (Waters, UK). 10 ACS Paragon Plus Environment
Page 11 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
1
For UHPLC-HDMSE data, processing and analysis was conducted by using
2
Progenesis QI Informatics (Nonlinear Dynamics, Newcastle, U.K.) in a standard
3
protocol 50 in which each UHPLC−MS run was imported as a raw file to obtain the ion-
4
intensity map, including m/z and retention time. As default, these ion maps were then
5
aligned in the retention-time direction. From the aligned runs, an aggregate run
6
representing the compounds in all samples was used for peak picking. This aggregate
7
was then compared with all runs, to ensure that the same ions are detected in every
8
run. Isotope and adduct deconvolution were applied in order to reduce the number of
9
features detected. Data were normalized according to total ion intensity. Metabolites
10
were identified by searches against their accurate masses in publicly available
11
databases, including the LIPID MAPS
12
(HMDB), 65and MetaScope (CCS database provided in Progenesis QI software), as
13
well as by fragmentation patterns, retention times, and CCS values, when available.
14
The platform LipidCCS 66 was also used for additional CCS comparison.
64database,
the Human Metabolome database
15 16
RESULTS AND DISCUSSION
17 18
DI-ESI-TWIM-MS of microalgae extracts
19
To determine the best application for a specific biomass, and also to evaluate
20
the process of algae production, researchers and biorefineries must have robust
21
analytical tools for the detailed analysis of these biomasses. We report two different
22
TWIM-MS analysis strategies for performing a quite challenging molecular
23
characterization of microalgae biomass extracts, focusing on triacylglycerols (TAGs),
24
as they are the major transesterifiable lipids precursors of fatty acid methyl esters
25
(FAMEs) for biodiesel production. 11 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 12 of 41
1
Figure 1 shows the full scan mass spectrum obtained by DI-ESI-TWIM-MS of
2
the microalgae extract Tetraselmis aff. chui “TG4”. It highlights the sample complexity,
3
and some examples of expected lipid classes that could be present in specific m/z
4
ranges. Figures S1-S16 show all other spectra. Quite different profiles are indeed
5
observed which shows that the composition of the algal biomass is considerably
6
altered as a function of the culture media and species or strains, and that these
7
changes are easily detected via DI-ESI-TWIM-MS. Note that determining how specific
8
classes of compounds vary more pronouncedly as a function of algae growth
9
parameters is critical to optimize production conditions.
10 11
FIGURE 1. DI- ESI(+)-TWIM-MS of the extract of Tetraselmis aff. chui cultivated in
12
culture media G4 (Sample “TG4”).
13
Data from all 16 DI-ESI-TWIM-MS spectra for each microalgae extract were
14
statistically evaluated by chemometrics (Figure 2) using principal component analysis
15
(PCA). Grouping occurred primarily by the microalgae genus, confirming that 12 ACS Paragon Plus Environment
Page 13 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
1
microalga metabolite profile is indeed a mainly characteristic feature of the genus.
2
Therefore, it follows that the genus could be the initial variable to be considered in a
3
study of alga prospecting for a specific biotechnological application. For example, after
4
defining the best genus, the culture medium and cultivation conditions could be studied
5
and optimized. This approach may also be suitable to compare with reference
6
samples, that is, microalgae that have been already shown to be suitable for a
7
particular application, or whose lipid profile has already been well characterized. It is a
8
simple and fast approach and provides a good response for an initial profiling of a given
9
set of samples.
10 11
FIGURE 2. Principal component analysis (PCA) of the 16 algal extracts. Note the
12
grouping by algae genus.
13 13 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 14 of 41
1
The algae extracts were also evaluated by their 2D drift time versus mass
2
spectra, considering the TWIM separation of the ionized lipids and metabolites in
3
samples. Figure 3 shows representative examples of 2D drift time versus m/z spectra
4
(detected ions with their m/z values) for some microalgae species. Figures S17-S32
5
show the spectra for all samples.
6 7
FIGURE 3. Representative two-dimensional drift time versus m/z of the MS detected
8
ions for the samples extracts of a) TG3; b) SPIZK, c) TG4 and d) CHLOSPS.
9 10
Different drift time tendencies, even those possessing overlap in their m/z
11
values, indicate that distinct classes of compounds are potentially separable. The
12
differences in the profiles of each algae extract becomes more evident upon such
13
visualization, and this approach allows for the profile screening of lipids. For example,
14
to investigate the TAG content in a lipid extract, since this class of compounds will be
15
distributed within a certain m/z range, (which, however, may be superimposed with
16
several other classes of lipids and metabolites, making the detection of this class 14 ACS Paragon Plus Environment
Page 15 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
1
difficult), and distributed in a tendency of characteristic drift times for a given
2
experimental condition. Therefore, this approach provides rapid turnaround with
3
respect to parameter changes and other decisions in algae culture studies, including
4
continuation or termination of a biorefinery process depending on whether a desired
5
product profile or other endpoint can be or has been met.
6
Assessment of the lipid profile of algal samples can be confirmed by an
7
additional approach, the binary comparison of drift time x m/z spectrum through the
8
HDMS compare software. In this approach, the ion mobility spectra are superimposed,
9
highlighting the classes of compounds that are more abundant in each sample,
10
generating a map in which each sample is marked with a different color for each
11
sample. Figure 4 shows the comparison of the spectrum of TG3 and a blend of
12
commercial vegetable oils (a mixture of soybean, corn, rapeseed, sunflower and olive
13
oils in even proportions that are knowingly composed by TAGs). Clearly, the TAG
14
abundance in sample TG3 is superimposed with the TAGs of the vegetable oil blend
15
(Figure 4). Figure S33 also shows another binary comparison of samples TG4 and
16
SPIKZ, being evident the differences in their drift plots, indicating that the sample
17
SPIKZ notably has a lower abundance of TAGs.
18
15 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 16 of 41
1 2
FIGURE 4. Fusion map comparing the “DT versus m/z” spectrum of sample TG3 and
3
a blend of commercial edible oils obtained with the DI-TWIM-MS approach. The insert
4
highlights the superimposed drift time regions for GL_TAG class in both samples.
5 6
The principal TAGs ions that show characteristic mobility tendencies can also
7
be further analyzed by their CCS values, manually determined via calibration with poly-
8
DL-alanine
9
samples (N2 1.05 mbar, height 30 V and wave velocity 650 m/s). Each selected ion has
10
its CCS experimentally determined by calibration using substances whose CCS is
11
known, thereby increasing data selectivity.67 Adding one more intrinsic physical-
12
chemical ion property such as the CCS, significantly also increases the confidence of
13
metabolite/lipid identification. 68 One of the most common calibrants for CCS values is
14
poly-DL-alanine, whose CCS values for its singly charged oligomers have been well
15
determined in N2 as drift gas.
standard solution infused in exactly the same TWIM conditions as the
16 ACS Paragon Plus Environment
Page 17 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
1
Figure 5 shows the experimentally determined CCS values (Ω in Å2)
2
(electronically available in Supp. Information) for the most abundant ions from m/z 800
3
to 1000, exemplified for the sample TG4. Notably, a clear CCS separation exists for
4
TAGs, resulting in a cluster possessing slightly higher CCS values, versus other
5
isobaric ions likely probably from other metabolites classes. This highly interesting
6
finding could be useful in assessing a qualitative response regarding TAG abundance
7
in algal samples, as this region of drift time x m/z would appear to be selective for the
8
TAG class. This useful spectral characteristic of TAGs can be used to inform the
9
optimization of algae cultivation for biodiesel production.
10 11
FIGURE 5. Experimentally derived CCS values (Ω in Å2) for the most abundant ions in
12
the sample TG4 obtained by DI-TIWM-MS, with the GL_TAG region highlighted.
13 14 17 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
1
Page 18 of 41
High-throughput lipids and metabolites characterization by UHPLC-HDMSE
2 3
To ultimately perform a comprehensive characterization of algae extracts,
4
additional MS/MS spectra is crucial in allowing full annotation. However, the manual
5
interpretation of MS/MS data obtained by DI-ESI-TWIM-MS of the extracts would be
6
extremely laborious and time consuming, due to the complexity of the samples that
7
present different classes of lipids and other metabolites. We therefore applied the
8
much more comprehensive UHPLC-HDMSE technique as a second approach to
9
analyze the lipids and metabolites of the algae samples. In addition to the exact mass
10
and CCS values obtained for precursor ions, MS/MS spectra are collected, generating
11
information about fragments, that can be compared to spectral databases and lead to
12
a tentative annotation.
13
Each chromatographic run, together with the MS, MS/MS and IMS data
14
associated with it, was imported to Progenesis QI software, which via comparison with
15
the LIPID MAPS, HMDB, and a search engine with a CCS database provided by
16
Waters
17
comparison of the precursor and fragment exact masses, isotope distribution,
18
fragmentation profile (in silico fragmentation or known experimental fragmentation
19
pathways) and CCS values. The combination of all these identification parameters
20
results in an overall compound identification score for each identified compound.
(MetaScope)
performs
the
identification
by
theoretical/experimental
21
From the 16 analyzed samples, all in the same conditions of analysis, 1251
22
different compounds were putatively annotated, within an m/z error of 10 ppm for both
23
precursor ion and fragments. Among these 1251 compounds: 1) only 158 could not be
24
identified by their fragments; 2) 30 of them were also identified by their CCS, assuming
25
a theoretical/experimental error lower than 4%; 3) the isotope similarities were from 18 ACS Paragon Plus Environment
Page 19 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
1
30.4 to 99.4, with an average of 82.1; 4) for the fragmented ions, the average
2
fragmentation score was 41.9 (ranging from 1 to 99.4); and finally, 5) the identification
3
score ranged from 30 to 59.1, with an average of 39.5. The identifications with the
4
highest scores were accepted and described in the accompanying spreadsheet with
5
the metabolomics and lipidomics description of this study, provided as electronic
6
Supporting Information. The number of compounds identified by their CCS values is
7
relatively low (30 compounds) due to limitation of the database used, as it is not as
8
broad as the LIPID MAPS or the HMDB. Among the 1251 compounds that were
9
putatively annotated, 210 were lipids, with the others categorized as “other
10
metabolites”. The lipids were also categorized into fatty acyls (FA), glycerolipids (GL),
11
glycerophospholipids (GP), sphingolipids (SP), sterol lipids (ST), prenol lipids (PR),
12
and saccharolipids (SL). Although TAG are also lipids (glycerolipids), this class was
13
categorized separately as “GL_TAG”, as we discuss and emphasize its importance for
14
biodiesel production.
15
From the normalized abundances of each deconvoluted annotated compound
16
per sample, several interpretations can be made. Figure 6 shows the lipidomics and
17
metabolomics results interpretations for all the samples. Figure 6a shows the sum of
18
the normalized abundance for each class of lipids and other metabolites, and Figure
19
6b shows only the normalized abundances for different lipid classes in the samples.
20
Figure 6c shows the percentage abundance of compounds identified as lipids and as
21
other metabolites, and Figure 6d shows the percentage abundance of lipid classes
22
distributed in each sample.
23
19 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 20 of 41
1 2
FIGURE 6. Sum of the normalized abundances of a) each lipids classes and other
3
metabolites identified in the samples and b) each lipid class identified in the samples;
4
c) Relative abundance of lipids and metabolites for each sample; d) Relative
5
distribution of lipid classes in each sample. Legends: fatty acyls (FA), glycerolipids
6
(GL), glycerophospholipids (GP), triacylglycerol (GL_TAG), sphingolipids (SP), sterol
7
lipids (ST), prenol lipids (PR), saccharolipids (SL).
8 9
Figure 6 data are not quantitative, meaning that they cannot be considered as
10
a “weight by weight %” measurement in the sample extracts as not all the reported
11
compounds have the same ionization behavior, implying different response factors.
12
Note that lipidomics or metabolomics analysis are comparative methods and would not
13
cover 100% of the compounds that are indeed present in a given sample. It is expected
14
that several other compounds remained undetected and/or unidentified, but a
15
comprehensive profile is not essential for comparisons and predictions. Note also that,
16
as recently reported by Dorrestein and co-workers
49
20 ACS Paragon Plus Environment
in a recent metabolomics study
Page 21 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
1
of algae and cyanobacteria, approximately 86% of the metabolomics signals detected
2
were not found in other available datasets, concluding that even using a very diverse
3
datasets, algae and cyanobacteria have unique features and families of metabolites
4
that are still uncharacterized. However, the normalized abundance of each class of
5
known compounds should serve as suitable screening for the alga biomass
6
composition and to understand how different processes may be affecting alga
7
composition.
8
Figures 6a and 6c point out that the abundance of compounds identified as
9
metabolites is higher than the compounds identified as lipids, as indeed expected, as
10
the number of potential metabolites is indeed much higher than the number of
11
compounds of the lipid class. The sample with the highest abundance of lipids was the
12
sample TG2 (Fig 6c), mainly distributed between GL (excepting GL_TAG – that is
13
highlighted separately) and GP. The sample with the highest % of GL_TAG was
14
DUNDEF_CHCl3 (Fig. 6d), but when comparing the sum of the normalized abundance
15
(Fig. 6b). It can be noted also that the samples DUNDEF_CHL3, TG3 and TG4 were
16
the ones presenting the highest abundances of compounds identified as TAGs. It
17
indicates that they would – at least in theory – provide better yields for the biodiesel
18
production, if it was a real case of a study of algae prospecting for biodiesel production.
19
The detection of some metabolites and ST compounds may have important
20
implications when alga biomass is used for nutraceutical products. When the
21
untargeted approach detects toxins or sterols compounds (i.e. testosterone), or other
22
classes of biologically active compounds, it is important to state at this point that further
23
studies must be conducted, and these compounds must be characterized using
24
targeted analysis to confirm the primary assumption of the untargeted analysis.
21 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 22 of 41
1
In fact, the DI-ESI-TWIM-MS data really converge with the CCS values
2
determined by UHPLC-HDMSE. Comparing the drift time versus m/z plot for a sample
3
obtained by the DI approach with the plot of all the experimental CCS values versus
4
m/z measured for all identified compounds, we can observe the same drift time
5
tendencies showing up in both cases. To illustrate that, Figure 7 compares the TG3
6
sample drift time plot, and the experimental CCS values determined for all the 1251
7
annotated compounds. We can highlight at least 4 different areas: I – a low abundance
8
very separated tendency, probably minor metabolites; II – the compounds identified as
9
TAGs, mainly from m/z 700 – 1000 and slightly higher CCS values; III – a very busy
10
region with several superimposed lipids and other metabolites; and IV – also a low
11
abundant separated tendency. We can also observe in what regions the lipid classes
12
tend to appear, which is helpful to detect misleading identifications if some of them
13
appear in a very distinct region. It can also help to choose classes of compounds and
14
take a closer look at their identification. The separation of distinct tendencies in the
15
sample TG3 are more evident because not all of the 1251 compounds are present in
16
sample TG3.
17
The use of more polarizable drift gasses such as CO2 has been proven to be an
18
alternative to increase the selectivity and classes separations in complex mixtures
19
such as crude oil.
20
calibrants (such as poly-DL-alanine) values in this gas are not yet available, as the
21
determination of this parameter in CO2 is much more complex. However, if only the
22
separation of classes of different compounds are needed, and no CCS values must be
23
determined, the use of CO2 can be a good alternative to better detect different classes
24
of lipids and metabolites in complex mixtures such as microalgae extracts.
59
On the other hand, databases of CCS values in CO2 or CCS
22 ACS Paragon Plus Environment
Page 23 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
1 2
FIGURE 7. Comparison of the two-dimensional drift time versus m/z plot for sample
3
TG3 with the CCS experimentally determined by UHPLC-HDMSE for all the 1251
4
compounds, highlighting the areas I, II, III and IV that could be detected in both plots.
5 6
Additional TAGs confirmation was made by comparing the experimental data of
7
measured CCS values with the ones available in the recently released CCS database,
8
LipidsCCS,
9
were determined in N2, as drift gas, so they are comparable. Only two compounds
10
identified as TAG had no theoretical CCS value available in LipidCCS dataset, which
11
were TG(10:0_8:0_8:0) and TG(21:0_22:6_22:6). For the other TAGs, the
12
experimental versus theoretical CCS error was mostly bellow to 10%, with 6.7%
13
average. The experimental values tended to be around 20 Ǻ2 positively biased, that is,
14
20 Ǻ2 on average larger than the theoretical values, but this minor systematic error
15
probably comes from the Synapt G2-Si CCS calibration with poly-DL-alanine step. In
16
general, therefore, the CCS were mostly in accordance with LipidCCS data base,
17
which shows that this parameter is actually very useful and helps further identification
18
and confirmation of compounds. The calculated CCS values obtained with DI-TWIM-
66
(Table S1). Both the measured and the LipidsCCS theoretical values
23 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 24 of 41
1
MS (Fig. 5) seem to be in accordance with theoretical data, being TAGs CCS values
2
mostly falling within 300 to 330 Å.
3
Another interesting approach that could be used for CCS determinations in both
4
DI-TWIM-MS and UHPLC-HDMSE is the use of a standard mixture of lipids of interest
5
with available theoretical CCS values.
6
CCS values could be determined more accurately, as the CCS calibrants and the
7
targeted lipid classes for a set of experimental conditions would exhibit the same gas
8
phase behavior.
66
In this way, it is expected that experimental
9
Finally, comparing the two analysis strategies presented in this work, it is
10
important to emphasize that the DI-TWIM-MS allows a rapid fingerprinting of
11
microalgae extracts, helping the visualization of different classes of lipids and
12
metabolites via mobility mass correlation curves such as the data presented in Fig. 7,
13
in which lipid classes such as TAGs can be detected in a specific m/z versus ion
14
mobility tendency. Moreover, from DI-TWIM-MS data, the binary comparison of the
15
two-dimensional drift time versus m/z spectrum of different samples can be applied,
16
for instance, to compare two cultivation conditions or two microalgae of different
17
species, highlighting the differences between them, and it can be very useful in the
18
biotechnology industry. However, a comprehensive molecular description with DI-
19
TWIM-MS is an extremely laborious task due to sample complexity, and not suitable
20
for routine analysis, as MS/MS data would have to be manually acquired. For that, if a
21
more detailed molecular characterization is required to understand what are the
22
metabolites or lipids that are affected by some specific cultivation condition, for
23
example, UHPLC-TWIM-HDMSE strategy allows annotation of metabolites and lipids in
24
samples considering also their CCS values as a specific molecular descriptor to
25
improve identification confidence. 24 ACS Paragon Plus Environment
Page 25 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
1
Analytical Chemistry
CONCLUSIONS
2
All the approaches demonstrated here have the potential to be applied as
3
methodologies for lipids and metabolites screening in real cases of microalgae
4
prospecting and can be implemented as routine both for research and in microalgae
5
biorefineries. Ion mobility mass spectrometry provided fast profile of microalgae
6
extracts, in which the new dimension of ion mobility separation reveals distinct classes
7
of compounds, especially triacylglycerols.
8
The variability of the lipids in the algae was found to be incredibly high and
9
sensitive to the cultivation parameters, but the statistical classification among the
10
samples indicated that the main parameter that influences the composition of the
11
extracts is the genus of the algae. Genus seems therefore to be an initial variable to
12
be considered in a study of algae prospecting for a specific biotechnological
13
application. For example, after defining the best genus, the culture medium and
14
cultivation conditions could be studied and optimized.
15
Statistical or binary comparison of the samples drift time plots spectrum seems
16
necessary, especially for comparison with reference samples, that is, with a microalga
17
that has been already shown to be suitable for a particular application, or whose lipid
18
profile has already been characterized. DI-TIWIM-MS has been shown therefore to be
19
a simple and fast approach and provides a good response for an initial profiling of a
20
given set of samples, but performing comprehensive identification of all the ions of the
21
samples can be quite laborious.
22
The high level of complexity of the samples requires a more powerful
23
methodology to perform a more global and detailed sample screening. For this, the
24
UHPLC-HDMSE technique was used to putatively annotate over 1200 compounds,
25
collectively in the 16 samples, based on intrinsic parameters of the detected ions (exact 25 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 26 of 41
1
mass, fragmentation pattern, isotope distribution and CCS). More than 200 were
2
annotated as lipids of several classes. Among the 16 samples evaluated in this study,
3
Tetraselmis aff. chuii, cultivated in F/2 medium plus fertilizers for 12 (TG3) and 16 days
4
(TG4), as well as biomass of Dunaliella salina produced in nitrogen-reduced Shaish
5
medium and extracted with CHCl3 (DUDEF_CHL3), were the ones with the highest
6
TAGs abundances, and are therefore more promising for biodiesel production within
7
the evaluated samples.
8
The methodologies explored in this work could be applied to microalgae
9
biorefineries to predict whether some specific algae will be viable for biodiesel
10
production or for other biotechnology applications, as well as help in studies of
11
microalgae cultivation improvements.
12 13
AKNOWLEDGEMENTS
14
We thank the State of São Paulo Research Foundation (FAPESP), State of Rio
15
de Janeiro Research Foundation (FAPERJ), the Brazilian National Council for
16
Scientific and Technological Development (CNPq) and the Financing Agency of
17
Studies and Projects (FINEP) for financial assistance. We gratefully acknowledge
18
Waters Brazil managers for opening their demo laboratory (Barueri, Brazil) to run the
19
UHPLC-HDMSE experiments. We also thank the National Institute of Technology for
20
microalgae biomasses donation and Dr. M. D. Bartberger for the scientific opinion in
21
the final work. Finally, we thank the referees of this work for their contribution to its
22
quality improvement.
23 24 26 ACS Paragon Plus Environment
Page 27 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
1
Analytical Chemistry
REFERENCES
(1) Raven, J. A.; Giordano, M. Algae, Current Biology, 2014, 24(13), R590–R595. (2) Nigel, D. H.; Lloyd, D. T.; Canvin, D. A. Culver Photosynthesis and Photorespiration in Algae, Plant Physiology, 1977, 59 (5), 936–940. (3) Pedersen, O.; Colmer, T.D.; Sand-Jensen, K. Underwater Photosynthesis of Submerged Plants – Recent Advances and Methods, Frontiers in Plant Science, 2013, 4, 1–19. (4) Bhattacharya, D.; Medlin, L. Algal Phylogeny and the Origin of Land Plants, Plant Physiology, 1998, 116 (1), 9–15. (5) Fasciotti, M. Perspectives for the use of biotechnology in green chemistry applied to biopolymers, fuels and organic synthesis: from concepts to a critical point of view, Sustainable Chemistry and Pharmacy, 2017, 6, 82–89. (6) Lü J.; Sheahan C.; Sheahan, C.; Fu, P. Metabolic engineering of algae for fourth generation biofuels production, Energy & Environmental Science, 2011, 4, 2451–2466. (7) Alam, F.; Mobin, S.; Chowdhury, H. Third Generation Biofuel from Algae, Procedia Engineering, 2015, 105 , 763–768. (8) Singh, A.; Nigam, P. S.; Murphy, J.D. Renewable fuels from algae: An answer to debatable land based fuels, Bioresource Technology, 2011, 102 (1), 10–16. (9) Scott, S. A.; Davey, M. P.; Dennis, J. S.; Horst, I.; Howe, C. J.; Lea-Smith, D.J.; Smith, A. G. Biodiesel from algae: challenges and prospects, Current Opinion in Biotechnology, 2010, 21 (3), 277–286. (10) Giordano, M.; Wang Q.; Microalgae for Industrial Purposes. In: Vaz Jr. S. (eds) Biomass and Green Chemistry, 2018, Springer, Cham. (11) Sun, X.; Wang, C.; Li, Z.; Wang, W.; Tong, Y. Wei, J. Microalgal cultivation in wastewater from the fermentation effluent in riboflavin (B2) manufacturing for biodiesel production, Bioresource Technolgy, 2013, 143, 499–504. (12) Miazek, K.; Kratky, L.; Sulc, R., et al. Effect of Organic Solvents on Microalgae Growth, Metabolism and Industrial Bioproduct Extraction: A Review. International Journal of Molecular Sciences, 2017, 18(7), 1429 (1-31). (13) Cuellar-Bermudez, S. P. et al. Nutrients utilization and contaminants removal. A review of two approaches of algae and cyanobacteria in wastewater, Algal Research, 2017, 24, 438–449. (14) Delrue, F.; Álvarez-Díaz, P. D.; Fon-Sing, S.; Fleury, G.; Sassi, J.-F. The environmental biorefinery: Using microalgae to remediate wastewater, a win-win paradigm. Energies, 2016, 9, 132. 27 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 28 of 41
(15) Kruse, O.; Hankamer, B. Microalgal hydrogen production. Current Trends in Biotechnology, 2010, 21, 238–243. (16) Yang, J.; Xian M, Su S, et al. Enhancing Production of Bio-Isoprene Using Hybrid MVA Pathway and Isoprene Synthase in E. coli. Williams, PLoS ONE, 2012, 7(4), e33509. (17) John, R. P.; Anisha, G.S.; Nampoothiri, K. M.; Pandey, A.; Micro and macroalgal biomass: A renewable source for bioethanol, Bioresource Technology, 2011, 102(1), 186–193. (18) Astumi, S.; Can, A. F.; Connor, M. R. et al., Metabolic Engineering of Escherichia coli for 1-butanol production, Metab. Eng., 2008, 10, 305–311. (19) Atsumi, S.; Higashide, W.; Liao J. C.; Direct photosynthetic recycling of carbon dioxide to isobutyraldehyde, Nature Biotechnology, 2009, 27, 1177–1180. (20) Mata, T. M.; Martins, A. A.; Caetano, N. S.; Microalgae for biodiesel production and other applications: A review. Renewable and Sustainable Energy Reviews, 2010, 14(1), 217–232. (21) Chisti, Y. Biodiesel from microalgae beats bioethanol. Trends in Biotechnology, 2008, 26 (3), 126–131. (22) Kerkhoven, E. J.; Pomraning, K. R.; Baker, S. E.; Nielsen, J. Regulation of aminoacid metabolism controls flux to lipid accumulation in Yarrowia lipolytica. npj Systems Biology and Applications, 2016, 2, 16005. (23) Ma, N.-L.; Aziz, A.; Teh, K.-Y.; Lam S. S.; Cha T.-S.; Metabolites Re-programming and Physiological Changes Induced in Scenedesmus regularis under Nitrate Treatment, Nature Scientific Reports, 2018, 8, 9746. DOI:10.1038/s41598-018-278940 (24) Sharma, A. K.; Sahoo, P. K.; Singhal, S.; Joshi, G. Exploration of upstream and downstream process for microwave assisted sustainable biodiesel production from microalgae Chlorella vulgaris, Bioresource Technology, 2016, 216, 793–800. (25) V. Ashokkumar, Zainal Salam, Palanivel Sathishkumar, Tony Hadibarata, Abdull Rahim Mohd Yusoff, Farid Nasir Ani, Exploration of fast growing Botryococcus sudeticus for upstream and downstream process in sustainable biofuels production, Journal of Cleaner Production, 2015, 92, 162–167. (26) Lieve, M.L.; Laurens, S. V.; Wychen, J. P.; McAllister, S. A., Dempster, T. A.; McGowen, J.; Pienkos, P.T. Strain, biochemistry, and cultivation-dependent measurement variability of algal biomass composition, Analytical Biochemistry, 2014, 452, 86–95. (27) Singh, S.; Kate, B. N.; Banerjee, U. C. Bioactive Compounds from Cyanobacteria and Microalgae: An Overview. Critical Reviews in Biotechnology, 2005, 25, 73–95. 28 ACS Paragon Plus Environment
Page 29 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
(28) Spolaore, P.; Joannis-Cassan, C.; Duran, E.; Isambert, A. Commercial applications of microalgae, J Biosci Bioeng, 2006, 101(2), 87–96. (29) Collard, F.; Blin, J. A review on pyrolysis of biomass constituents: Mechanisms and composition of the products obtained from the conversion of cellulose, hemicelluloses and lignin, Renewable and Sustainable Energy Reviews, 2014, 38, 594–608. (30) Slocombe, S. P.; Zhang, Q.; Ross, M.; Anderson, A.; Thomas, N. J.; Lapresa, A.; Rad-Menéndez, C.; Campbell, C. N.; Black, K. D.; Stanley M. S.; Day. J. G. Unlocking nature’s treasure-chest: screening for oleaginous algae. Nature Scientific Reports, 2015, 9844, 1–17. (31) Pollesello, P.; Toffanin, R.; Murano, E.; Paoletti, S.; Rizzo, R.; Kvam, B. J. Lipid extracts from different algal species: 1H and13C-NMR spectroscopic studies as a new tool to screen differences in the composition of fatty acids, sterols and carotenoids, Journal of Applied Phycology, 1992, 4, 315–322. (32) Sarpal, A. S.; Silva, P. R. M.; Martins, J. L.; Amaral, J. J.; Monnerat, M. M.;. Cunha, V. S.; Daroda, R. J.; de Souza, W. Biodiesel Potential of Oleaginous Yeast Biomass by NMR Spectroscopic Techniques, Energy Fuels, 2014, 28(6), 3766–3777. (33) Dean, A. P.; Sigee, D. C.; Estrada, B.; Pittman, J. K.; Using FTIR spectroscopy for rapid determination of lipid accumulation in response to nitrogen limitation in freshwater microalgae. Bioresource Technology , 2010, 101, 4499–4507. (34) Pavel Pořízka, et. al. Algal Biomass Analysis by Laser-Based Analytical Techniques—A Review, Sensors (Basel), 2014,14(9), 17725–17752. (35) Sarpal, A.S.; Teixeira, C.M.; Silva, P.R.; Lima, G. M.; Silva S.R.; Monteiro, T.V.; Cunha, V.S.; Daroda, R.J. Determination of lipid content of oleaginous microalgal biomass by NMR spectroscopic and GC-MS techniques, Analytical and Bioanalytical Chemistry 2015, 407(13),3799–3816. (36) Chopra, A.; Tewari, A. K.; Vatsala, S.; Kumar, R.; Sarpal, A. S.; Basu, B. Determination of Polyunsaturated Fatty Esters (PUFA) in Biodiesel by GC/GC–MS and 1H‐NMR Techniques, Journal of the American Oil Chemists' Society, 2011, 88, 1285– 1296. (37) S.; Bogialli, M.; Bruno, R.; Curini, A.; Di Corcia, C.; Fanali, A. Laganà, Monitoring Algal Toxins in Lake Water by Liquid Chromatography Tandem Mass Spectrometry Environ. Sci. Technol., 2006, 40 (9), 2917–2923. (38) Khan, A.; Eikani, C. K.; Khan, H.; Iavarone, A.T.; Pesavento, J. J. Characterization of Chlamydomonas reinhardtii Core Histones by Top-Down Mass Spectrometry Reveals Unique Algae-specific Variants and Post-translational Modifications, Journal of proteome research, 2017, 17(1), 23–32. 29 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 30 of 41
(39) Zendong, Z.; McCarron, P.; Herrenknecht, C.; Sibat, M.; Amzil, Z.; Cole, R. B., Philipp Hess, High resolution mass spectrometry for quantitative analysis and untargeted screening of algal toxins in mussels and passive samplers, Journal of Chromatography A, 2015, 1416, 10–21. (40) Klejdus, B.; Lojková, L.; Plaza, M.; Šnóblová, M.; Štěrbová, D. Hyphenated technique for the extraction and determination of isoflavones in algae: Ultrasoundassisted supercritical fluid extraction followed by fast chromatography with tandem mass spectrometry, Journal of Chromatography A, 2010, 1217(51), 7956–7965. (41) Jones, J.; Manning S.; Montoya, M.; Keller K.; Poenie, M.; Extraction of Algal Lipids and Their Analysis by HPLC and Mass Spectrometry, Journal of the American Oil Chemist’s Society, 2012, 89(8), 1371–1381. (42) Samburova V.; Lemos M. S.; Hiibel S.; Hoekman S. K.; Cushman, J. C.; Zielinska, B. Analysis of Triacylglycerols and Free Fatty Acids in Algae Using Ultra‐Performance Liquid Chromatography Mass Spectrometry, Journal of the American Oil Chemist's, Society, 2013, 90(1), 53–64. (43) Řezanka, T., Vyhnálek, O.; Podojil, M. Identification of sterols and alcohols produced by green algae of the genera Chlorella and Scenedesmus by means of gas chromatography—mass spectrometry, Folia Microbiol, 1986, 31:44. doi.org/10.1007/BF02928678 (44) Anastyuk, S. D.; Shevchenko, N. M.; Nazarenko, E. L.; Dmitrenok, P. S.; Zvyagintseva, T. N. Structural analysis of a fucoidan from the brown alga Fucus evanescens by MALDI-TOF and tandem ESI mass spectrometry, Carbohydrate Research, 2009, 344 (6), 779-787. (45) Han, J.; Calvin M. Hydrocarbon distribution of algae and bacteria, and microbiological activity in sediments, PNAS, 1969, 64(2), 436–443. (46) Ma J.; Xiao R.; Li J.; Li J.; Shi B.; Liang Y.; Lu, W.; Chen, L. Headspace solid‐phase microextraction with on‐fiber derivatization for the determination of aldehydes in algae by gas chromatography–mass spectrometry, Journal of Separation Science, 2011, 34(12), 1477–83. (47) Klejdus, B.; Lojková, L.; Plaza, M.; Šnóblová, M.; Štěrbová, D.; Hyphenated technique for the extraction and determination of isoflavones in algae: Ultrasoundassisted supercritical fluid extraction followed by fast chromatography with tandem mass spectrometry, Journal of Chromatography A, 2010, 1217(51), 7956–7965. (48) Kadam, S.U.; Tiwari, B. K.; O’Donnell, C.P. Application of Novel Extraction Technologies for Bioactives from Marine Algae, Journal of Agricultural and Food Chemistry, 2013, 61 (20), 4667–4675. 30 ACS Paragon Plus Environment
Page 31 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
(49) Luzzatto-Knaan , T.; Garg, N.; Wang, M.; Glukhov, E.; Peng, Y.; Ackermann, G.; Amir, A.; Duggan, B. M.; Ryazanov, S.; Gerwick, L.; Knight, R.; Alexandrov, T.; Bandeira, N.; Gerwick, W.H.; Dorrestein, P. C. Digitizing mass spectrometry data to explore the chemical diversity and distribution of marine cyanobacteria and algae, eLife, 2017, 6, e24214. (50) Paglia, G.; Astarita, G. Metabolomics and lipidomics using traveling-wave ion mobility mass spectrometry. Nature Protocols, 2017, 12, 797–813. (51) Paglia, G.; Angel, P.; Williams, J.P.; Richardson, K.; Olivos, H.J.; Thompson, J. W.; Menikarachchi, L.; Lai, S.; Walsh, C.; Moseley, A.; Plumb, R. S.; Grant, D.F.; Palsson, B. O.; Langridge, J.; Geromanos, S.; Astarita, G. Ion mobility-derived collision cross section as an additional measure for lipid fingerprinting and identification. Analytical Chemistry, 2015, 87(2), 1137–1144 (52) Paglia, G.; Williams, J.P.; Menikarachchi, L.; Thompson, J.W.; Tyldesley-Worster, R.; Halldórsson, S.; Rolfsson, O.; Moseley, A.; Grant., D.; Langridge, J.; Palsson, B.O.; Astarita, G. Ion mobility derived collision cross sections to support metabolomics applications. Analytical Chemistry, 2014, 86(8), 3985–3993; (53) Paglia, G.; Kliman, M.; Claude, E.; Geromanos, S.; Astarita, G. Applications of ionmobility mass spectrometry for lipid analysis. Analytical and Bioanalytical Chemistry, 2015, 407(17), 4995–5007. (54) Souza, G.H.M.F.; Guest, P.C.; Martins-de-Souza D. LC-MS(E), Multiplex MS/MS, Ion Mobility, and Label-Free Quantitation in Clinical Proteomics. Methods in Molecular Biology, 2017, 1546, 57–73. (55) Kanu, A. B.; Dwivedi, P.; Tam, M.; Matz, L.; Hill Jr. H. H. Ion mobility mass spectrometry. Journal of Mass Spectrometry, 2008, 43, 1–22. (56) Cumeras, R.; Figueras, E.; Davis, C. E.; Baumbach, J. I.; Gràcia, I. Review on Ion Mobility Spectrometry. Part 1: current instrumentation, Analyst, 2015, 140, 1376– 1390. (57) Fasciotti, M.; Lalli, P. M.; Heerdt, G.; Steffen, R. A.; Corilo, Y. E.; Sá, G. F.; Daroda, R. J.; Reis, F. A. M.; Morgon, N. H.; Pereira, R. C. L.; Eberlin, M. N.; Klitzke, C. F. Structure-drift time relationships in ion mobility mass spectrometry, International Journal for Ion Mobility Spectrometry, 2013, 1, 1−16. 31 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 32 of 41
(58) Valentine, S. J.; Kulchania, M.; Barnes, C. A. S.; Clemmer, D. E. Multidimensional separations of complex peptide mixtures: a combined high-performance liquid chromatography/ion mobility/time-of-flight mass spectrometry approach, International Journal of Mass Spectrometry, 2001, 212, 97−109. (59) A) Fasciotti, M.; Lalli, P. M.; Klitzke, C. F.; Corilo, Y. E.; Pudenzi, M. A.;. Pereira, R. C. L.; Bastos, W.; Daroda, R. J.; Eberlin, M. N. Petroleomics by Traveling Wave Ion Mobility–Mass Spectrometry Using CO2 as a Drift Gas, Energy & Fuels, 2013, 27 (12), 7277−7286; B) Santos, J. M.; Galaverna, R. S.; Pudenzi, M. A.; Schmidt, E. M.; Sanders, N. L.; Kurulugama, R. T.; Mordehai, A.; Stafford, G. C.; Wisniewski Jr, A.; Eberlin, M. N. Petroleomics by ion mobility mass spectrometry: resolution and characterization of contaminants and additives in crude oils and petrofuels, Analytical Methods, 2015, 7, 4450−4463. (60) McCullagh, M.; Douce, D.; Van Hoeck, E.; Goscinny, S. Exploring the Complexity of Steviol Glycosides Analysis Using Ion Mobility Mass Spectrometry, Analytical Chemistry, 2018, 90 (7), 4585–4595. (61) Benigni, P.; Thompson, C. J.; M. E.; Ridgeway, M. A.; Park, Fernandez-Lima, F. Targeted High-Resolution Ion Mobility Separation Coupled to Ultrahigh-Resolution Mass Spectrometry of Endocrine Disruptors in Complex Mixtures, Analytical Chemistry, 2015, 87(8), 4321–4325. (62) Bligh, E. G.; Dyer, W. J. A rapid method of total lipid extraction and purification. Canadian Journal of Biochemistry and Physiology, 1959, 37, 911–917 (63) Sarpal, A. S., Costa, I. C. R., Teixeira, C. M. L. L., Filocomo, D., Candido R, et al. Investigation of Biodiesel Potential of Biomasses of Microalgaes Chlorella, Spirulina and Tetraselmis by NMR and GC-MS Techniques. Journal of Biotechnology and Biomaterials, 2016, 6(1), doi:10.4172/2155-952X.1000220. (64) The LIPID MAPS Lipidomics Gateway, http://www.lipidmaps.org. (65) a) Wishart D. S., Tzur D. , Knox C, et al., HMDB: the Human Metabolome Database. Nucleic Acids Res. 2007Jan;35 (Database issue):D521-6. 17202168; b) Wishart DS, Knox C, Guo AC, et al., HMDB: a knowledgebase for the human metabolome. Nucleic Acids Res. 2009 37(Database issue):D603-610. 18953024; c) Wishart DS, Jewison T, Guo AC, Wilson M, Knox C, et al., HMDB 3.0 — The Human Metabolome Database in 2013. Nucleic Acids Res. 2013. Jan 1;41(D1):D801-7. 23161693; d) Wishart DS, Feunang YD, Marcu A, Guo AC, Liang K, et al., HMDB 4.0 — The Human Metabolome Database for 2018. Nucleic Acids Res. 2018. Jan 4;46(D1):D608-17.
32 ACS Paragon Plus Environment
Page 33 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
(66) Zhou, Z.; Tu, J.; Xin, X.; Shen, X.; Zhu, Z.-J. LipidCCS: Prediction of Collision Cross-Section Values for Lipids with High Precision to Support Ion Mobility-Mass Spectrometry based Lipidomics, Analytical Chemistry, 2017, 89, 9559–9566. (67) Campuzano, I.; Bush, M. F.; Robinson, C. V.; Beaumont, C.; Richardson, K.; Kim, H.; Kim H. I. Structural Characterization of Drug-like Compounds by Ion Mobility Mass Spectrometry: Comparison of Theoretical and Experimentally Derived Nitrogen Collision Cross Sections, Analytical Chemistry, 2012 84 (2), 1026–1033. (68) Zhou, Z.; Tu J.; Zhu, Z.-J. Advancing the large-scale CCS data base for metabolomics and lipidomics at the machine-learning era, Current Opinion in Chemical Biology, 2018, 42, 34–41.
33 ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
SCHEME 1. Sixteen different microalgae biomasses analyzed in this work. 135x144mm (96 x 96 DPI)
ACS Paragon Plus Environment
Page 34 of 41
Page 35 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
FIGURE 1. DI- ESI(+)-TWIM-MS of the extract of Tetraselmis aff. chui cultivated in culture media G4 (Sample “TG4”). 390x211mm (96 x 96 DPI)
ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
FIGURE 2. Principal component analysis (PCA) of the 16 algal extracts. Note the grouping by algae genus 314x227mm (96 x 96 DPI)
ACS Paragon Plus Environment
Page 36 of 41
Page 37 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
FIGURE 3. Representative two-dimensional drift time versus m/z of the MS detected ions for the samples extracts of a) TG3; b) SPIZK, c) TG4 and d) CHLOSPS. 241x136mm (96 x 96 DPI)
ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
FIGURE 4. Fusion map comparing the “DT versus m/z” spectrum of sample TG3 and a blend of commercial edible oils obtained with the DI-TWIM-MS approach. The insert highlights the superimposed drift time regions for GL_TAG class in both samples. 479x254mm (96 x 96 DPI)
ACS Paragon Plus Environment
Page 38 of 41
Page 39 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
FIGURE 5. Experimentally derived CCS values (Ω in Å2) for the most abundant ions in the sample TG4 obtained by DI-TIWM-MS, with the GL_TAG region highlighted. 336x222mm (150 x 150 DPI)
ACS Paragon Plus Environment
Analytical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
FIGURE 6. Sum of the normalized abundances of a) each lipids classes and other metabolites identified in the samples and b) each lipid class identified in the samples; c) Relative abundance of lipids and metabolites for each sample; d) Relative distribution of lipid classes in each sample. Legends: fatty acyls (FA), glycerolipids (GL), glycerophospholipids (GP), triacylglycerol (GL_TAG), sphingolipids (SP), sterol lipids (ST), prenol lipids (PR), saccharolipids (SL). 352x212mm (150 x 150 DPI)
ACS Paragon Plus Environment
Page 40 of 41
Page 41 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Analytical Chemistry
FIGURE 7. Comparison of the two-dimensional drift time versus m/z plot for sample TG3 with the CCS experimentally determined by UHPLC-HDMSE for all the 1251 compounds, highlighting the areas I, II, III and IV that could be detected in both plots. 527x206mm (96 x 96 DPI)
ACS Paragon Plus Environment