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Food and Beverage Chemistry/Biochemistry
A triple quadrupole and a hybrid quadrupole orbitrap mass spectrometer in comparison for polyphenol quantitation Chiara Cavaliere, michela antonelli, Anna Laura Capriotti, Giorgia La Barbera, Carmela Maria Montone, Susy Piovesana, and Aldo Laganà J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.8b07163 • Publication Date (Web): 12 Apr 2019 Downloaded from http://pubs.acs.org on April 12, 2019
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Journal of Agricultural and Food Chemistry
A triple quadrupole and a hybrid quadrupole orbitrap mass spectrometer in comparison for polyphenol quantitation
Chiara Cavaliere, Michela Antonelli, Anna Laura Capriotti, Giorgia La Barbera*, Carmela Maria Montone, Susy Piovesana and Aldo Laganà. Department of Chemistry, University of Rome “La Sapienza”, Piazzale Aldo Moro 5, Rome, Italy
Corresponding author: Giorgia La Barbera, PhD Università di Roma "La Sapienza" Dipartimento di Chimica P.le Aldo Moro 5, 00185 Rome (Italy) Phone: +39 0649913834 E-mail
[email protected] 1 ACS Paragon Plus Environment
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1
Abstract
2
Liquid chromatography coupled to low resolution mass spectrometry (LRMS) has historically been
3
a popular approach for compound quantitation. Recently, high resolution mass spectrometry (HRMS)
4
technical developments led to the introduction of new approaches for quantitative analysis. Whereas
5
the performances of HRMS have been largely assessed for qualitative purposes, there are still
6
questions about its suitability for quantitative analysis. Several papers on LRMS and HRMS
7
comparison have been published, however, none of them was applied to polyphenol quantitation. In
8
this work, a comparison between HRMS, operated in data dependent acquisition mode, and LRMS,
9
operated in selected-reaction-monitoring mode, was performed for polyphenol quantitation in wine.
10
The two techniques were evaluated in terms of sensitivity, linearity range, matrix effect and precision,
11
showing the better performances of HRMS. The suitability of HRMS for quantitation purposes as
12
well as qualitative screening makes HRMS the new technique of choice for both targeted and
13
untargeted analysis.
14
Keywords:
15
high resolution mass spectrometry; low resolution mass spectrometry; polyphenols; quantitation;
16
wine.
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Introduction
18
In the last decade, targeted screening by means of ultra-high performance liquid chromatography–
19
tandem mass spectrometry (UHPLC–MS/MS) became a popular approach for the analysis and
20
quantitation of several analytes such as drugs1, metabolites2, contaminants3, and phytochemicals4. In
21
particular, triple-quadrupole mass spectrometers (QqQ-MS) in selected-reaction-monitoring (SRM)
22
mode is considered the work horse for quantitative analysis, because of its good sensitivity and wide
23
dynamic range5. In the last years, however, the development of new improved UHPLC
24
instrumentations, together with the advent of high resolution mass spectrometry (HRMS), led to the
25
introduction of new approaches and techniques for targeted quantitative analysis. With the modern
26
hybrid high resolution mass spectrometers such as quadrupole-orbitrap-MS (Q-orbitrap-MS) and
27
quadrupole-time-of-flight-MS (Q-TOF), new acquisition modes can be chosen to both record high
28
resolution full scan and MS/MS spectra, allowing sensitive quantitative and qualitative analysis at the
29
same time6. UHPLC-HRMS technique, showing the versatile capability of performing quantitative
30
and qualitative analyses, can be seen as a true alternative to low resolution QqQ-MS. Indeed, in
31
contrast to targeted SRM modes by QqQ-MS, HRMS instrumentations operated in data dependent
32
acquisition (DDA) or data independent acquisition (DIA), can be applied for both targeted and
33
untargeted screening approaches. A more complete overview of the composition and content of a
34
sample extract could be preferred to targeted quantitation methods for assessing a more
35
comprehensive characterization of samples.
36
HRMS versatility is an unquestionable potentiality which, together with the increasingly availability
37
of new affordable HRMS instrumentations in the market, could shift the attention in favour of HRMS
38
for both qualitative and quantitative analysis7–13. However, whereas the potentialities of HRMS for
39
qualitative analyses have been largely assessed, there are still remaining questions on its quantitative
40
analysis performances, especially when compared with QqQ-MS operated in SRM mode.
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Several papers have been published on the comparison between QqQ-MS and HRMS
42
instrumentations for quantitative analysis, showing either better, equal or worse performances of
43
HRMS platforms compared to QqQ-MS. Data reported in the literature are often inconsistent with
44
each others, leading to the need of further deeper and comprehensive evaluations. Moreover, whereas
45
several studies on comparison between LRMS and HRMS performances have been focused on
46
contaminants, drugs and metabolites8,10,11,14,15, no study on the quantitative performances of QqQ-MS
47
versus HRMS instruments for polyphenol quantitation has been published in the literature.
48
Plants have a very large metabolome including substances that differ in molecular weight, physico-
49
chemical characteristics and dynamic range16,17. Thus, despite the developing of recent
50
instrumentations, the quantitative analysis of phytochemicals remains challenging. SRM acquisition
51
with QqQ-MS is a well-established procedure which has been largely used for polyphenol
52
quantification4. However, the Orbitrap-based instruments can also provide reproducible
53
quantification results and large linear range18. Nevertheless, they are rarely exploited for polyphenol
54
quantification17.
55
The lack of a comparison between QqQ-MS and HRMS platforms for polyphenol analysis is
56
surprising considering the importance of polyphenol characterization in vegetable and food matrices,
57
and the challenge in the developing of quantitation methods for these complex matrices. However, it
58
could be justified by the difficulty in availability of blank samples and the unpredictable matrix effects
59
on compound quantification. The standard addition method is the most suitable one to overcome these
60
limits. However, the setting of a standard addition method for the comparison of two instruments is
61
a particular taught issue, due to the difference of instrumental response. In our opinion, however,
62
assessing the performances of LRMS and HRMS for quantitative analysis of polyphenols is a
63
particularly interesting and unexplored issue requiring further investigation.
64
On this purpose, we aimed at focusing our work on evaluating the performances of a QqQ-MS and a
65
hybrid Q-orbitrap-MS for the quantitative analysis of polyphenols in rosé wine. In particular, 50
66
polyphenols belonging to different classes such as flavonoids, isoflavones, proanthocyanidins, 4 ACS Paragon Plus Environment
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anthocyanins and phenolic acids were analysed by means of UHPLC coupled by electrospray
68
ionization (ESI) to either a TSQ vantage QqQ-MS or a Qexactive hybrid Q-orbitrap-MS. Same
69
calibration samples of polyphenols were injected on the two systems performing the same
70
chromatographic separation. Method validation was performed in parallel by assessing limit of
71
detection (LOD), limit of quantification (LOQ), linearity of dynamic range, matrix effect (ME) and
72
precision.
73 74
Materials and methods:
75
Standard solutions and samples
76
Reagents and materials
77
Ultrapure water H2O Optima LC-MS Grade and Acetonitrile Optima LC-MS Grade were purchased
78
from Fisher Scientific (Rodano, Italy). Methanol HiPerSolv CHROMANORM ultra LC-MS and
79
Ethanol HiPerSolv CHROMANORM ultra LC-MS were purchased from VWR International (Milan,
80
Italy), Formic acid ultrapure for mass spectroscopy was purchased from Fluka analytical. The
81
following reference standard compounds were purchased from Sigma-Aldrich (St.Louis, MO, USA):
82
biochanin A, caffeic acid, callistephin (pelargonidin-3-glucoside), catechin gallate, cinnamic acid,
83
coumaric acid, coumestrol, cyanidin chloride, daidzein, diosmetin, epicatechin, epicatechin gallate,
84
equol, ferulic acid, flavone, formononetin, gallic acid, glycitein, hesperetin, kaempferol, kuromanin
85
chloride (cyanidin-3-O-glucoside), malvidin 3-galactoside chloride, myricetin, naringenin, peonidin-
86
3-O-glucoside chloride, primuletin, procyanidin B1, procyanidin B2, quercetin dihydrate, quercetin-
87
3-O-glucoside,
88
trihydroxyflavone. The following reference standard compounds were purchased from Extrasynthese
89
(Lyon, France): catechin, eriodictyol, genistein, hesperidin (hesperetin-7-O-glucoside), isorhamnetin,
90
luteolin, luteolin-7-O-glucoside, malvidin chloride, morin, phloretin, syringetin. The following
resveratrol,
rutin
(quercetin-3-O-rutinoside),
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acid,
taxifolin,
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reference standard compounds were purchased from Fluka Biochemika (Milan, Italy): apigenin,
92
apigenin-7-glucoside, chlorogenic acid hemihydrate, genistin (genistein-7-glucoside).
93
Rosé wine sample
94
Rosé wine, with an alcoholic content of 12.5% (v/v %), was purchased in a common supermarket. As
95
soon as the wine bottle was opened, rosé wine was aliquoted under nitrogen flow and the aliquots
96
were stored at -20°C. Prior to analysis rosé wine samples were thawed at room temperature, filtered
97
through Acrodisc syringe filters with a 0.2 μm GH Polypropilene membrane (Pall, Ann Arbor, MI,
98
USA) and either directly analysed or added with the reference standard compounds for building
99
matrix matched calibration curve, as reported in the following paragraphs.
100
Stock solutions
101
Certified 1 gL-1 standard solutions of 50 reference standard compounds were dissolved in methanol
102
or acetonitrile. Individual stock solutions were diluted in MeOH at 10 ng µl-1 for direct injection into
103
the mass spectrometers. In addition, individual stock solutions were diluted with MeOH at the
104
appropriate concentration to prepare a mixture stock solution. Starting from the most concentrated
105
mixture stock solution (indicated as 1x), 5x, 10x, 50x, 100x, 500x, 1000x, 5000x, 10000x solutions
106
were prepared for successive dilution with MeOH. The concentration of each compound in the
107
mixture stock solutions, at several dilution levels, has been reported in Table S1.
108
Finally, biochanin A and equol, that were chosen as internal standards for negative and positive
109
polarity acquisition, were diluted at 5 ng µl-1 and 2.5 ng µl-1, respectively. All stock solutions were
110
stored at –20◦C.
111
Calibration curves
112
A solvent calibration curve. including 10 dilution levels (included blank sample). was built as follows:
113
20 µl of each mixture stock solution reported in the previous paragraph was added to 400 µl of water,
114
60 µl of Ethanol and 10 µl of biochanin A C=5 ng µl-1 and 10 µl of equol C=2.5 ng µl-1. In addition, 6 ACS Paragon Plus Environment
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a blank solution was prepared substituting the mixture stock solution with 20 µl of MeOH. The final
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composition of each working solution was H2O/MeOH/EtOH = 80/8/12 (v/v/v).
117
A matrix matched calibration curve, including 10 dilution levels, was built as follows: 20 µl of each
118
mixture stock solution reported in the previous paragraph was added to 460 µl of wine, and 10 µl of
119
biochanin A C=5 ng µl-1 and 10 µl of equol C=2.5 ng µl-1. In addition, a blank solution was prepared
120
substituting the mixture stock solution with 20 µl of MeOH. Based on the wine alcoholic
121
concentration reported in the label, the final composition of each working solution was
122
H2O/MeOH/EtOH = 80.5/8/11.5 (v/v/v).
123
The concentration of each compound in the mixture working solutions, at several dilution levels, have
124
been reported in Table S1.
125
All working solutions were splitted in three aliquots, placed in injection vials and stored at -20°C
126
prior to instrumental analysis.
127 128
UHPLC and mass spectrometric conditions
129
UHPLC systems
130
The MS instruments were connected to two similar LC systems. In particular, the QqQ-MS was
131
connected to a UHPLC Ultimate 3000 binary pump (Thermo Fisher Scientific, Brema, Germany),
132
whereas the Q-orbitrap-MS was connected to an UHPLC Vanquish binary pump H (Thermo Fisher
133
Scientific, Brema, Germany). Both UHPLC systems are equipped with a thermostatted autosampler
134
and a thermostatted column compartment. The chromatographic separation was carried out on a
135
Kinetex core–shell C18 column (100 mm × 2.1 mm) with particles size of 2.6 μm (Phenomenex,
136
Torrance, CA, USA) at 40°C and at a flow rate of 600 μL min−1. The mobile phase was H2O–
137
HCOOH (99.9:0.1 v/v; solvent A) and ACN–HCOOH (99.9:0.1 v/v; solvent B); the elution
138
gradient was as follows: 5% solvent B for 3 min, 5% solvent B to 15% solvent B in 10 min, 15%
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solvent B to 35% solvent B in 15 min, 35% solvent B to 50% solvent B in 5 min, 99% solvent B
140
for 5 min, 5% solvent B for 8 min. The injection volume was 5 μL for all the samples.
141
ESI
142
The chromatographic systems were coupled to the mass spectrometers by means of the same heated
143
ESI source design H-ESI-II (Thermo Fisher Scientific, Brema, Germany). Exact same position (C)
144
and conditions were used on the Q-orbitrap-MS and QqQ-MS. In particular, the ESI source
145
parameters were set as follows: capillary temperature 275°C in positive mode, 350°C in negative
146
mode; sheath gas 50 arbitrary units (a.u.) in positive mode, 55 a.u. in negative mode; auxiliary gas
147
15 a.u.; sweep gas 2.25 a.u. in positive mode, 3 a.u. in negative mode; spray voltage 3500 V in
148
positive mode, 2500 V in negative mode; auxiliary gas heater temperature 450°C in positive mode,
149
300°C in negative mode.
150
Q-orbitrap-MS
151
The HRMS instrument was a Q Exactive hybrid quadrupole Orbitrap mass spectrometer (Thermo
152
Fisher Scientific, Brema, Germany). The detection was conducted in DDA in both positive and
153
negative polarity mode. MS data were acquired in the m/z 100–600 with a resolution (full width at
154
half maximum, FWHM, at m/z 200) of 35,000. The automatic gain control (AGC) target value was
155
200,000 in full-scan mode. The maximum ion injection time was 100 ms. The isolation window
156
width was 2 m/z. MS2 fragmentation was performed on the five most intense ions detected in full-
157
scan mode with a resolution FWHM of 17,500. The AGC target value was 100,000. Dynamic
158
exclusion was set to 3s. An exclusion list was set containing the ions most commonly detected in
159
the blank and an inclusion list was set containing the m/z and retention time of the monitored target
160
compounds. Fragmentation was achieved in the higher energy collisional dissociation (HCD) cell at
161
a normalized collision energy (NCE) of 80. The analytes of interest are reported in Table 1 together
162
with their retention time, precursor ion mass and product ion scan. The Q-orbitrap-MS was calibrated
163
every two days by using the Pierce LTQ Velos ESI Positive Ion Calibration Solution (Thermo Fisher 8 ACS Paragon Plus Environment
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Scientific, Brema, Germany), and the Pierce ESI Negative Ion Calibration Solution (Thermo Fisher
165
Scientific, Brema, Germany) injecting it in infusion at 5 μL min-1. The sweep cone and ion transfer
166
tube were washed every day prior to analysis. LC-HRMS data acquisition, peak integration and
167
quantitation were performed by using the software Xcalibur v.2.1 (Thermo Fisher Scientific, Brema,
168
Germany).
169
QqQ-MS
170
The QqQ-MS was a TSQ Vantage EMR triple quadrupole mass spectrometer (Thermo Fisher
171
Scientific, Brema, Germany). The detection was conducted in SRM acquisition, in both positive and
172
negative polarity mode. Two transitions were monitored for each compound at unit resolution and
173
using a collision gas pressure of 1 mTorr. Ionization and fragmentation conditions were optimized
174
by injecting in the ESI source the individual standard working solutions by direct infusion at a flow
175
of 5 µL min-1.
176
Briefly, the s-lens parameter was optimized in full scan monitoring the intensity of the precursor ion,
177
in order to maximize the precursor ion sensitivity. Then the five most abundant product ions formed
178
from the precursor ion were selected and the collision energy optimized per product ion in order to
179
maximize the product ion sensitivity. The first most abundant and the second most abundant or
180
selective product ion were selected for monitoring the analytes. Moreover, each analyte transitions
181
were monitored over 1 minute window time around the analyte retention time, to enhance sensitivity
182
and selectivity of the measurements. Cycle time was set to 0.35 s. The optimized SRM parameters
183
are reported in Table 2.
184
The QqQ-MS was calibrated before ionization and fragmentation parameters optimization and,
185
later, once a month by using the vendor calibration mixture solution injecting it in infusion at 5 μL
186
min-1. The sweep cone and ion transfer tube were washed every day prior to analysis. LC-MS data
187
acquisition, peak integration and quantitation were performed by using the software Xcalibur v.2.1
188
(Thermo Fisher Scientific, Brema, Germany). 9 ACS Paragon Plus Environment
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Data acquisition and processing
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LC-MS and LC-HRMS data acquisition, peak integration and quantitation were performed by using
191
the software Xcalibur v.2.1 (Thermo Fisher Scientific, Brema, Germany). In particular, peak
192
integration for quantification was carried out by means of Xcalibur Quan Browser using the following
193
parameters: retention time window 10 s, smoothing points 1, baseline windows 40 (QqQ-MS) and 60
194
(Q-orbitrap-MS), area noise factor 5 (QqQ-MS) and 2 (Q-orbitrap-MS), peak noise factor 10,
195
minimum peak height S/N 3. One processing method was set for HRMS data where the extracted ion
196
chromatograms (XIC) of theoretical m/z ± 5 ppm were used for peak integration. Two processing
197
methods were set for QqQ-MS, one based on the highest abundant and one on the second highest
198
abundant transition for peak integration.
199
Quantitative QqQ-MS and Q-orbitrap-MS performance
200
Identification and quantitation of analytes
201
Polyphenols under investigation were identified in the spiked matrices by following the Commission
202
Directive 2002/657/EC19. Based on these regulations a minimum number of 4 identification points is
203
required for the unequivocal identification of analytes. For LRMS 1 point is assigned for the detection
204
of the precursor mass, 1.5 points to the detection of the first transition, 1.5 points to the detection of
205
the second transition. For HRMS 2 points are assigned for the detection of the precursor mass, 2.5
206
points for the detection of one ion fragment. Therefore, for LRMS, compounds were identified based
207
on the presence of the highest abundant transition and the second highest abundant transition, in
208
comparison with the authentic reference standard. For HRMS, compounds were identified based on
209
the detection of both the precursor ion and the most abundant fragment ion with a mass tolerance of
210
5 ppm, in comparison with the authentic reference standard. Other than identifying the analytes based
211
on the precursor and fragment ions also the retention time has been taken into consideration.
212
Compounds were assessed as unequivocally identified when the FWHM was between 90-110% the
213
FWHM of the reference standard compound chromatographic peak. Moreover, also the shift in 10 ACS Paragon Plus Environment
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retention time of the analyte and the reference standard compound was allowed to be not higher than
215
5%. The quantification by means of QqQ-MS was accomplished by integrating the peak related to
216
the highest intense transition (quantifier), whereas the quantification by Q-orbitrap-MS was
217
accomplished by integrating the peak obtained by the extraction of the precursor accurate mass with
218
an extraction window of 5 ppm.
219
Calibration graphs and linearity range
220
A matrix matched (M) calibration curve and a standard in solvent curve (S) were built at 9
221
concentration levels. Peak area ratios (compound/internal standards) were considered as response (y)
222
and polyphenols concentrations as independent variable (x). A linear regression model with weighting
223
factor 1/x was used to build the calibration curves. Intercept q, slope m, and correlation coefficient
224
R2 were calculated. The dynamic linear range was evaluated for each analyte based on the R2 values.
225
The mM, qM, RM2, mS, qS and RS2 values related to both matrix matched and standard in solvent
226
calibration curves are reported for each analyte in Table S2.
227
LOD, LOQ and sensitivity
228
For QqQ-MS, LOD and LOQ calculation was accomplished by integrating the area of the second
229
highest abundant transition and the highest abundant transition of each analyte, respectively. For Q-
230
orbitrap-MS, both LOD and LOQ calculation was accomplished by integrating the peak of the
231
precursor ion of each analyte, obtained with an extraction window of 5 ppm, and showing the presence
232
of the most abundant fragment with a mass tolerance of 5 ppm. The matrix matched and matrix free
233
calibration curves were built as explained before, but considering the peak area without IS
234
normalization as response (Y). LOD and LOQ values were calculated based on the following
235
expressions:
236
LODM= 3 𝛅qM/mM
LOQM = 10 𝛅qM/mM
237
LODS= 3 𝛅qS/mS
LOQS = 10 𝛅qS/mS
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238
Where 𝛅qM is the standard deviation on the intercept qM and mM is the slope of the matrix matched
239
calibration curve, and qS is the standard deviation on the intercept qS and mS is the slope of the
240
standard in solvent calibration curve. LOQ values were used for the comparison of Q-orbitrap-MS
241
and QqQ-MS sensitivity. LODM, LOQM, LODS, LOQS values related to both matrix matched and
242
standard in solvent calibration curves are reported for each analyte in Table S3.
243
Matrix effect
244
Due to the absence of sample pretreatment recovery values could not be calculated, whereas ME was
245
calculated by the following formula: ME = mM/mS * 100
246 247
Where mM and mS are the slopes of the matrix matched and standard in solvent curve, respectively,
248
built as described in paragraph 2.3.2, i.e by the areas normalized for the IS. ME values are reported
249
in Table S4.
250
Precision
251
The intra-day and inter-day method precision was calculated at two concentration level, i.e level 4
252
and level 8 of the matrix matched calibration curve. In particular, 5 replicates were run in the same
253
day for evaluating intra-day precision and 5 replicates were run in 5 different days for evaluating
254
inter-day precision. Mean and relative standard deviation (RSD) values, calculated on the area of the
255
integrated peaks of the replicates, were used to assess method precision, that is reported for each
256
analyte in Table S5.
257 258
Results and discussion
259
Experimental setup for the comparison
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Nowadays, several quantitative LC-HRMS methods have been already developed and validated for
261
all kinds of analytes and matrices8,20–23. This strongly suggests that HRMS is a fully appropriate
262
technique for absolute quantification. However, a head-to-head comparison between recent HRMS
263
and QqQ-MS platforms is still required in order to assess the performances of the new instruments
264
when compared with the historical work-horse for quantification. Such comparison should be taken
265
with care since many parameters can influence the sensitivity, selectivity and reproducibility of
266
results: the chromatographic method, the position or design of the ionization sources, the MS
267
parameters and acquisition modes as well as the matrix of choice. All the mentioned parameters have
268
been taken in to account in this work, in which an evaluation and comparison of the performance of
269
a QqQ-MS and a hybrid Q-orbitrap-MS for the quantitative analysis of polyphenols in rosé wine was
270
carried out.
271
The chromatographic method was chosen based on a previous comprehensive evaluation carried out
272
by La Barbera et al.24 on the analysis of polyphenols in strawberry. The Kinetex C18 XB column was
273
evaluated under several gradient, mobile phases and temperature in order to assure the best
274
chromatographic separation of polyphenol standard compounds and polyphenols in a complex
275
phytochemical mixture. These conditions were kept unchanged in the analysis with both the HRMS
276
platform and LRMS platform. Although the LC chromatographic pumps coupled with the two
277
instruments are slightly different, aside from a constant shift of about 1 minute in the retention time
278
the separation of the 50 standards evaluated in this work gave the same results in terms of peak shape,
279
reproducibility and peak resolution.
280
Concerning the ionization source parameters, also the conditions optimized in the previous work of
281
La Barbera et al. 24 were used for the analysis. These parameters were indeed previously optimized
282
by direct injection combining a flow of 10 µl min-1 of the standard solution at a C=10 ng µl-1 with a
283
flow of 600 µl min-1 of the mobile phases in the initial gradient conditions by means of a tee union.
284
The ionization parameters were kept constant in the HRMS and LRMS platforms which were both
285
equipped with the same exact ESI source, i.e H-ESI II. Also, the distance between the needle and the 13 ACS Paragon Plus Environment
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286
ion transfer tube was optimized in order to obtain the highest ionization efficiency and was kept
287
unchanged for the two MS systems.
288
The same mass spectrometric acquisition mode as used in the work of La Barbera et al.24, i.e. DDA,
289
was chosen for the polyphenol quantification by the HRMS instrument. Although the method
290
presented by La Barbera et al.24 was aimed at performing a comprehensive qualitative analysis of
291
complex phytochemical matrices, it was optimized in order to obtain a minimum of 10 data points
292
per peak and to allow the simultaneous acquisition of MS and MS/MS spectra in a wide m/z range,
293
that it is a primary need for quantitative analysis as well. Several parameters such as dynamic
294
exclusion, the presence of an exclusion list, the number of ions to be fragmented i.e. TOP5 or TOP10,
295
a stepped fragmentation at two energy collisions in contrast to a single energy collision, were
296
evaluated. Also, resolution was set at 35,000 (FWHM at m/z 200) for the MS scan and at 17,500 for
297
the MS2 scan, resulting in a mass error not higher than 3 ppm. Higher resolution for the MS scan did
298
not significantly reduce the mass error, but it decreased the scan rate, resulting in a minor number of
299
data point per chromatographic peak. All the parameters set in the work of La Barbera et al.24 were
300
kept unchanged in this work. However, due to the different purpose of this work, namely the targeted
301
screening and quantification of a limited number of compounds, a smaller mass range acquisition was
302
set (100-600 m/z) and an inclusion list containing the precursor mass and retention time of the analytes
303
of interest was introduced to assure their MS/MS spectra acquisition. The choice of the DDA
304
acquisition mode, over the other available acquisition modes that could potentially be used for
305
quantitative analysis in HRMS such as full scan HR, DIA, targeted single ion monitoring (SIM) DDA
306
and parallel reaction monitoring (PRM), was due to several reasons. Firstly, methods implying the
307
acquisition of MS/MS spectra are mandatory in order to remove isobaric interferences and to assure
308
a high confidence of identification. Based on the Commission Directive 2002/657/EC 19, a minimum
309
number of 4 point is required for the unambiguous identification of a compound, which in the case
310
of HRMS platforms requires the detection of both the precursor ion and at least one fragment.
311
Although several articles underscore the quantitative capabilities of HRMS instruments whereas 14 ACS Paragon Plus Environment
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312
performing MS/MS acquisitions9,10,20, several papers suggests instead that PRM, DIA and other
313
acquisition modes including MS/MS acquisition are good methods for quantitative analysis5,25.
314
Unfortunately, official guidelines do not specify the preferred acquisition mode for quantification by
315
HRMS platforms26, and the choice is left to the researchers’ purposes. In our work, the DDA method
316
was chosen because of its ease of use, not requiring any particular optimization prior to analysis.
317
Moreover, DDA is one of the most used acquisition mode by users, allowing both targeted
318
quantification and untargeted identification, when needed. Concerning the QqQ-MS, the scheduled
319
SRM acquisition mode was used for the analysis of polyphenols. Indeed, when the regular SRM
320
acquisition mode was operated, by monitoring two transitions for each analyte during the whole
321
chromatographic run, only one or two data points per chromatographic peak were obtained.
322
Monitoring such a high number of transitions at the same time causes very long scan time not allowing
323
to acquire a sufficient number of data points per peak, losing in sensitivity and goodness of the peak
324
shape and not allowing a reliable quantification. On the contrary, a scheduled SRM acquisition mode,
325
by setting the specific retention time of each analyte with a retention time tolerance of one minute,
326
allowed to increase the number of data points per peaks. In addition, the cycle time was varied to
327
obtain at least 10 points per peaks, exactly like in the acquisition performed with the HRMS
328
spectrometer. As mentioned above, two transitions were chosen for each analyte, the first most intense
329
(quantifier) and the second most intense (qualifier). In the case of the second transition, H2O or CO
330
neutral losses or neutral losses common to other coeluting analytes were avoided when possible, in
331
order to assure the selectivity of the method.
332
In Table 1, the analytes of interests monitored by Q-orbitrap-MS have been reported together with
333
their retention time, precursor ion mass and fragment ion mass. In Table 2 all the mass spectrometric
334
conditions optimized for each compound by QqQ-MS have been reported, i.e retention time,
335
quantifier and qualifier transitions, S-lens and collision energies.
336
Aside from the choice of the proper chromatographic separation and mass spectrometric acquisition
337
modes, also the choice of the matrix was accomplished by taking into consideration several concerns 15 ACS Paragon Plus Environment
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338
and based on both data literature and practical considerations. Wine is known to be a rich source of
339
polyphenols, making their identification and quantitation an appealing topic, as stated by the high
340
number of publication found in the literature27–30. Moreover, its analysis does not require any sample
341
preparation or analytes extraction, minimizing the effect of sample handling errors on the evaluation
342
of the performances of the instruments under investigation. However, the high quantity of
343
polyphenols present in this matrix makes impossible the use of blank samples for developing a
344
standard quantification method. Therefore, standard addition method was chosen because considered
345
the most suitable for the instrumental evaluation. Setting the standard addition method for the
346
comparison of the two instruments was a particular taught issue, due to the high abundance of
347
endogenous polyphenols in the matrix. When using standard addition method, indeed, poor results
348
will be obtained unless the concentration of the spiked analyte is more than five times the analyte
349
concentration (so long as that is consistent with the linear range of the analytical method)31. In order
350
to respect this constrain, several types of red wines were evaluated to assess their phenolic
351
composition. The content of polyphenols in red wine was shown to be too high to allow a proper
352
supplementation in the matrix. The dilution of the sample, at the same time, would have represented
353
an approximation of the real system, not allowing a reliable evaluation of matrix effect. Rosé wine
354
matrix was shown to contain lower quantities of polyphenols but maintaining a quite similar
355
complexity compared to red wine. Therefore, rosé wine was chosen as the most suitable matrix for
356
this study. The polyphenols found to be present in rosé wines showed a very heterogeneous range of
357
signal intensities, requiring the addition of each analyte at a specific concentration. Therefore, the
358
concentrations reported for the stock mixture solution were chosen based on both the initial content
359
of each analyte in the matrix and their signal response. Although these concerns have been taken into
360
account, in some cases, the standard addition was not sufficient to allow a signal 5 times higher than
361
the endogenous sample, at the lowest spiking levels. In these cases, it was not possible to build the
362
matrix matched calibration curve, and the instruments comparison was carried out based on the
363
standard solvent curve. 16 ACS Paragon Plus Environment
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364 365
Method validation for the comparison
366
Quantitative performance of the Q-orbitrap-MS and QqQ-MS was compared by the injection of the
367
exact same spiked samples in the two MS instruments and evaluating methods sensitivity, precision,
368
linear dynamic range, and matrix effect. In order to make such an evaluation, the solvent standard
369
calibration curves and the matrix matched calibration curves were built over four orders of magnitude.
370
The values of the slope, the intercept and the squared correlation coefficient R2 are reported in Table
371
S2. The first information obtained from the calibration curves is that both instruments show a pretty
372
good linear range over the explored order of magnitudes. In particular, coefficient RS2 obtained by
373
the solvent standard calibration curve in positive polarity was in the range 0.967-0.9999 and 0.9754-
374
0.9996 for Q-orbitrap-MS and QqQ-MS, respectively. Coefficient RS2 obtained by the solvent
375
standard calibration curve in negative polarity was in the range 0.970-0.9996 and 0.976-0.9996 for
376
Q-orbitrap-MS and QqQ-MS, respectively. Coefficient RM2 obtained by the matrix matched
377
calibration curve in positive polarity was in the range 0.97-0.9991 and 0.987-0.997 for Q-orbitrap-
378
MS and QqQ-MS, respectively. Finally, coefficient RM2 obtained by the matrix matched calibration
379
curve in negative polarity was in the range 0.979-0.9982 and 0.98-0.9996 for Q-orbitrap-MS and
380
QqQ-MS, respectively. The high abundance of endogenous polyphenols in rosé wine together with
381
the low response of some analytes limited the possibility of exploring higher concentration, due to
382
the need of spiking a too high quantity of reference standard compounds. The explored range of
383
linearity was however higher when compared with previous papers on quantitation in wine28,30. From
384
the comparison, any significant difference was found between the two instruments. Only a slight
385
better performance in favour of QqQ-MS was detected, mostly in negative polarity, for few
386
compounds, showing higher R2 in QqQ-MS than in Q-orbitrap-MS. This finding is confirmed by
387
several previous works on QqQ-MS and HRMS platforms comparison, showing very similar dynamic
17 ACS Paragon Plus Environment
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388
range and linearity when using the newest HRMS spectrometers 9,21 on the contrary of the “old” Q-
389
TOF MS32.
390
Whereas the linearity did not show any significant differences between the QqQ-MS and Q-orbitrap-
391
MS, the outcome of instrument comparison was sensibly different in the case of sensitivity.
392
Sensitivity was evaluated based on the calculated LOQ values. Indeed, whereas for HRMS extracted
393
accurate mass is used for peak integration and calculation of both LOQ and LOD, for QqQ-MS the
394
highest abundance transition is used for peak integration and LOQ calculation, and the second highest
395
abundant for peak integration and LOD calculation. For this reason, LOD values were not considered
396
to be comparable between the two instruments and LOQ was the only parameters used for the
397
comparison of Q-orbitrap-MS and QqQ-MS sensitivity. LOQS calculated from the solvent standard
398
calibration curve in positive polarity was in the range 2.2-162 µg L-1 and 4.2-645 µg L-1 for Q-
399
orbitrap-MS and QqQ-MS, respectively. LOQS calculated from the solvent standard calibration curve
400
in negative polarity was in the range 0.42-804 µg L-1 and 0.109-150 µg L-1 for Q-orbitrap-MS and
401
QqQ-MS, respectively. LOQM calculated from the matrix matched calibration curve in positive
402
polarity was in the range 1.0-2718 µg L-1 and 6-126 µg L-1 for Q-orbitrap-MS and QqQ-MS,
403
respectively. LOQM calculated from the matrix matched calibration curve in negative polarity was in
404
the range 4.4-4355 µg L-1 and 2.8-12087 µg L-1 for Q-orbitrap-MS and QqQ-MS, respectively.
405
However, although some of the minimum and maximum values of these ranges result to be higher
406
for Q-orbitrap-MS than of QqQ there is to take into account that they are not referred to the same
407
compounds. Most of the compounds with a high value of LOQ for Q-orbitrap-MS were not detected
408
at all by QqQ-MS. The values of LOQS and LOQM both in positive and negative polarity and for
409
both instruments are reported in Table S3. As shown in Table S3, several LOQM values are not
410
reported either because the standard addition was not sufficient to allow the building of the calibration
411
curve, or because, in the case of endogenous compounds, LOQM could not be assessed. In these cases,
412
the comparison of the instruments was accomplished by evaluating the LOQS. As shown in Table S3,
413
almost the totality of the analytes showed lower levels of LOQM and LOQS in the HRMS instrument 18 ACS Paragon Plus Environment
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Journal of Agricultural and Food Chemistry
414
demonstrating its higher performance in terms of sensitivity. This is in contrast with recent works on
415
comparison between the QqQ-MS and HRMS instruments, showing comparable limits of quantitation
416
in the two platforms. In particular, several papers showed that LRMS instruments were more
417
sensitive, equally sensitive, or less sensitive than HRMS instruments depending on the analysed
418
compounds5,10. The lack of an evaluation of QqQ-MS in comparison with HRMS platforms for the
419
analysis of polyphenols could justify the new finding that, in contrast to other similar papers, shows
420
the extremely better performance of HRMS instrumentation. In other works on polyphenol
421
quantitation with either QqQ-MS or HRMS platforms lower, similar or higher values of LOQ were
422
reported. However, these results are not often comparable because of the different analysed matrices
423
and the different approaches used for the calculation of LOQ values. The reported works on
424
polyphenols quantitation in wine, instead, and one specific work in which a multi-residual method
425
was applied for polyphenols quantitation in rosé wine by means of QqQ-MS, reported very similar
426
values of LOQ when compared with our results29,30,33–35.
427
A particularly interesting observation on calculated LOQ values, when the calculation was possible
428
for both the standard in solvent and matrix matched calibration curve, is the higher response of some
429
analytes when spiked in the matrix compared to the solvent, in the QqQ-MS analysis. This
430
observation was confirmed by the calculation of ME, resulting in values higher than 100% for all the
431
analytes in the QqQ-MS and few analytes in Q-orbitrap-MS. In particular, as shown in Table S4,
432
whereas in negative ionization mode Q-orbitrap-MS showed ME ranging from 80% to 100%, in
433
positive ionization mode it showed ME ranging from 100% to 120%. On the contrary, in both positive
434
and negative ionization mode, QqQ-MS resulted in ME much higher than 100% in the range of 120-
435
150%. The phenomenon of ME in HPLC-MS is due to several causes, among which the ionization
436
phenomenon is the most responsible of signal suppression or enhancement. The ionization efficiency,
437
indeed, depends on the physico-chemical properties of the analyte and the other molecules present at
438
the ionization interface. In ESI, the eluent from the chromatographic column is nebulized into charged
439
droplets, where a competition starts between the analyte and co-analyte for the proton transfer to take 19 ACS Paragon Plus Environment
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440
place36,37. Usually, coeluting polar co-analytes and apolar co-analytes should result in analyte signal
441
enhancement and suppression, respectively. Whereas the presence of polar compounds in an
442
acqueous matrix, such as wine, could be the explanation for the signal enhancement revealed for some
443
of the compounds with both QqQ-MS and Q-orbitrap-MS, it does not explain the different percentage
444
of signal enhancement between the two instruments. Considering that the same matrix, the same
445
chromatographic condition and the same ESI source were used for instrumental comparison, this
446
evidence should be explained by a post-interface phenomenon. As demonstrated by Kaufmann et
447
al.38, whereas the ion optics and the first quadrupole will always affect the signal the same way for
448
both techniques used, another source of signal changes can be found in the C-trap present in the Q-
449
orbitrap-MS instrument. Filling the C-trap is limited with both ion population and time, and in the
450
presence of a rich matrix, minor ions can be loss, which can explain the different ME values for Q-
451
orbitrap-MS compared to QqQ-MS. Aside from these observations, considering that acceptable ME
452
values are within 80% and 120%, the comparison of the two instruments resulted in better
453
performances for Q-orbitrap-MS compared to QqQ-MS.
454
The last parameter evaluated for QqQ-MS and Q-orbitrap-MS comparison is the precision, expressed
455
as RSD% calculated on the area of the integrated peaks of the replicates, that is reported for both
456
instruments, in positive and negative polarity mode, and at two concentration levels in Table S5.
457
Intra-day precision and inter-day precision showed RSD values below 5% and 10% for most of the
458
analytes with Q-orbitrap-MS, respectively. On the contrary, several analytes showed values higher
459
than 10% for both intra-day precision and inter-day precision with QqQ-MS. Therefore, on the
460
contrary of previous works showing similar precision in LRMS and HRMS, in this work better
461
performance in terms of precision was shown for the HRMS platform.8,20–22
462
In order to summarize and better visualize the results of comparison, an arbitrary score system was
463
applied on the parameters used for the evaluation. In particular, for range linearity comparison, score
464
2 was assigned when R2 was higher than 0.99, score 1 when R2 was higher than 0.98, score 0 when
465
R2 was lower than 0.98. For LOQ values comparison, score 1 and 0 were assigned to the technique 20 ACS Paragon Plus Environment
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Journal of Agricultural and Food Chemistry
466
showing the lowest and highest LOQ value, respectively. For ME evaluation, score 3 was assigned if
467
the deviation from 100% was lower than 10%, score 2 if the deviation was lower than 20%, score 0
468
if it was higher than 50. Finally, for intra-day precision comparison, score 2 was assigned when
469
RSD% was lower than 5%, score 1 when lower than 10%, and score 0 when higher than 10%, whereas
470
for inter-day precision, score 2 was assigned when RSD% was lower than 10%, score 1 when lower
471
than 20%, and score 0 when higher than 20%. In some cases, due to the lower response of some
472
analytes in QqQ-MS compared to Q-orbitrap-MS, either the endogenous polyphenols could only be
473
detected by Q-orbitrap-MS or the calibration curve could not be built for QqQ-MS. In these cases,
474
because of the impossibility of calculating LOQ, ME, R2 or RSD % values for either one or the other
475
instrument, the score was not assigned to neither of the two instruments, to avoid that sensitivity could
476
affect also the evaluation of the other parameters. The sum of the scores assigned to RS and RM, LOQS
477
and LOQM, ME, intra-day precision and inter-day precision, both in positive and negative ionization
478
mode for each individual analyte, was considered for instrumental comparison. Figure 1 reports the
479
calculated scores for the investigated analytes. As shown in the Figure the total score resulted to be
480
much higher in HRMS instrument with a high contribution of sensitivity, ME and precision. Only
481
linearity was slightly in favor of QqQ-MS as already mentioned above. Furthermore, the analytes
482
reported in Figure 1 were grouped based on the polyphenol class they belong to, in order to detect a
483
specific class dependent trend. Unluckily, no particular trend was observed.
484
The better performance showed for Q-orbitrap-MS in comparison with QqQ-MS can be due to several
485
reasons. Firstly, there is to take into consideration that the showed results are mainly dependent on
486
the acquisition mode chosen for the Q-orbitrap MS. Indeed, other acquisition modes such as full scan
487
HR, DIA, SIM, PRM could have led to different results in terms of either sensitivity or selectivity.
488
The choice of the DDA acquisition mode over the others was due to: the need for allowing analyte
489
identity confirmation by MS/MS spectra; the higher applicability and easy of use of this method in
490
comparison with other methods were prior parameters optimization is needed; the possibility of this
491
method over targeted methods of allowing a retrospective identification of unexpected compounds in 21 ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
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492
addition to the quantitation of targeted analytes. This choice strongly affected the results of the LRMS
493
and HRMS platforms comparison, leading to the conclusion that that Q-orbitrap-MS operated in DDA
494
mode, shows better performances compared to QqQ-MS operated in SRM mode.
495
In QqQ-MS an SRM acquisition mode by monitoring two transitions was used, because monitoring
496
only one transition might result in false positive identifications for individual compounds and thus at
497
least two transitions are required. However, several limitations become evident: under the constraints
498
of at least two transitions for the identification, SRM methods are typically limited to about 100–150
499
target analytes depending on chromatographic separation, as otherwise accuracy or sensitivity
500
deteriorate due to an insufficient temporal peak resolution or too short acquisition times for the
501
individual MS/MS transitions, respectively. When the number of target analytes is limited the
502
problem can be overcome. In this case, indeed, QqQ analyzer in its SRM mode results the most
503
adequate one for quantitative methods, due to its robustness and allowing a reliable quantification of
504
known compounds.
505
HRMS offers promising solutions to the limitation of analysing high number of analytes. All
506
compounds present in a sample can be determined simultaneously with HRMS instruments operating
507
in full-scan mode and fragmented by means of acquisition modes such as DDA, making no
508
preselection of compounds and associated SRM transitions necessary. In theory, the presence of an
509
unlimited number of compounds can be investigated at proper sensitivity, without requiring the
510
preselection of analytes. However, on qTOF instruments, these capabilities are impaired by the
511
limited sensitivity, which is about 1–2 orders of magnitude lower than those of QqQ-MS instruments
512
in SRM mode, and the limited dynamic range which is about 10-fold below that of QqQ-MS. Thus,
513
qTOF instruments have been used only occasionally for quantification and one established strategy
514
is to use QqQ-MS for quantification and a separate qTOF analytical run for confirmation. The
515
Orbitrap instrument offers a better dynamic range and a sensitivity close to that of many QqQ-MS
516
instruments, thus allowing for quantification and confirmation in a single analytical run39. Several
517
publications describing the new generation of HRMS systems and highlighting differences between 22 ACS Paragon Plus Environment
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Journal of Agricultural and Food Chemistry
40
518
LRMS and HRMS capabilities for targeted quantification
are available, and now show equal or
519
better performances of HRMS platforms compared to QqQ-MS.
520
HRMS allows a robust targeted quantification, but also compound identification, metabolite
521
phenotyping, and retrospective data treatment, which can be a true advantage for research on
522
unexpected unknown compounds. Due to the high-quality information, by combining sensitive full-
523
spectrum data and high mass accuracy, HRMS is a promising technique that has opened new horizons
524
in both identification and quantification of a wide range of known and unknown compounds.
525
In conclusion, in this work, the comparison between a QqQ-MS and a Q-orbitrap-MS for quantitation
526
of polyphenols resulted in better performance of HRMS over LRMS platform in terms of sensitivity,
527
precision and ME. The obtained results confirm the most recent findings suggesting the suitability of
528
HRMS for quantitation purposes. However, in the last published papers, comparable results between
529
low resolution and high resolution mass spectrometers have been reported for quantitation purposes.
530
In this work, HRMS platform showed a definitely better quantitative performance compared to the
531
QqQ-MS, for almost the totality of the investigated analytes. Sensitivity, robustness, user friendliness
532
and versatility makes HRMS platform a key instrument for performing both qualitative and
533
quantitative analysis. The quantitative performance shown with the tested HRMS instrument in this
534
article and many other reports, together with the growing needs for a global metabolite phenotyping,
535
leads to the consideration of HRMS as the new technique of choice for targeted and non targeted, as
536
well as qualitative and quantitative analysis, in several research fields.
537
Abbreviations used
538
Automatic gain control (AGC); Data dependent acquisition (DDA); Data independent acquisition
539
(DIA); Electrospray ionization (ESI); Extracted ion chromatogram (XIC); Full width at half
540
maximum (FWHM); High resolution mass spectrometry (HRMS); Higher energy collisional
541
dissociation (HCD); Limit of detection (LOD); Limit of Quantification (LOQ); Low resolution mass
542
spectrometry (LRMS); Mass spectrometry (MS); Matrix effect (ME); Matrix matched (M); 23 ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Page 24 of 35
543
Normalized collision energy (NCE); Parallel reaction monitoring (PRM); Quadrupole orbitrap mass
544
spectrometer (Q-orbitrap-MS); Quadrupole time-of-flight mass spectrometer (Q-TOF-MS); Relative
545
standard deviation (RSD); Selected reaction monitoring (SRM); Single ion monitoring (SIM);
546
Standard in solvent (S); Tandem mass spectrometry (MS/MS); Triple quadrupole mass spectrometry
547
(QqQ-MS); Ultra-high performance liquid chromatography (UHPLC)
548
Conflict of interest
549
The authors declare no competing financial interest.
550
Supporting information description
551
Table S1 shows the concentration of the investigated analytes at several dilution levels for both the
552
mixture stock solution and the mixture working solution. Table S2 shows the values of the slope,
553
intercept and squared correlation coefficient R2 extrapolated from both the matrix matched and
554
standard in solvent calibration curves, in positive and negative polarity mode, for both instruments.
555
Table S3 shows the values of LODM, LOQM, LODS, LOQS calculated from both matrix matched and
556
standard in solvent calibration curve, in both positive and negative polarity mode, for both
557
instruments. Table S4 shows the matrix effect values calculated for both instruments and in both
558
polarity modes. Table S5 shows the intra-day and inter-day precision expressed as relative standard
559
deviation (RSD), calculated on the area of the integrated peaks of five replicates, for both instruments,
560
in positive and negative polarity mode, at two concentration levels.
561
24 ACS Paragon Plus Environment
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562
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del Mar Gómez-Ramos, M.; Rajski, Ł.; Heinzen, H.; Fernández-Alba, A. R. Liquid chromatography Orbitrap mass spectrometry with simultaneous full scan and tandem MS/MS for highly selective pesticide residue analysis. Anal. Bioanal. Chem. 2015, 407 (21), 6317– 6326. Kafkas, Ebru Oz, A. T. Superfood and Functional Food - An Overview of Their Processing and Utilization; 2017. La Barbera, G.; Capriotti, A. L.; Cavaliere, C.; Montone, C. M.; Piovesana, S.; Samperi, R.; Zenezini Chiozzi, R.; Laganà, A. Liquid chromatography-high resolution mass spectrometry for the analysis of phytochemicals in vegetal-derived food and beverages. Food Res. Int. 2017, 100 (1), 28–52. Gómez-Ramos, M. M.; Ferrer, C.; Malato, O.; Agüera, A.; Fernández-Alba, A. R. Liquid chromatography-high-resolution mass spectrometry for pesticide residue analysis in fruit and vegetables: Screening and quantitative studies. Journal of Chromatography A. 2013, pp 24– 37. European Commission. Decision EC 657/2002 of 12 August 2002 implementing Council Directive 96/23/EC concerning the performance of analytical methods and the interpretation of results; 2002; Vol. L 221, pp 8–36. Chindarkar, N. S.; Park, H. D.; Stone, J. A.; Fitzgerald, R. L. Comparison of different time of flight-mass spectrometry modes for small molecule quantitative analysis. J. Anal. Toxicol. 2015, 39, 675–685. Henry, H.; Sobhi, H. R.; Scheibner, O.; Bromirski, M.; Nimkar, S. B.; Rochat, B. Comparison between a high-resolution single-stage Orbitrap and a triple quadrupole mass spectrometer for quantitative analyses of drugs. Rapid Commun. Mass Spectrom. 2012, 26, 499–509. Bruce, S. J.; Rochat, B.; Béguin, A.; Pesse, B.; Guessous, I.; Boulat, O.; Henry, H. Analysis and quantification of vitamin D metabolites in serum by ultra-performance liquid chromatography coupled to tandem mass spectrometry and high-resolution mass spectrometry - A method comparison and validation. Rapid Commun. Mass Spectrom. 2013, 27, 200–206. Kaufmann, A.; Butcher, P.; Maden, K.; Walker, S.; Widmer, M. Determination of nitrofuran and chloramphenicol residues by high resolution mass spectrometry versus tandem quadrupole mass spectrometry. Anal. Chim. Acta 2015, 862, 41–52. La Barbera, G.; Capriotti, A. L.; Cavaliere, C.; Piovesana, S.; Samperi, R.; Zenezini Chiozzi, R.; Laganà, A. Comprehensive polyphenol profiling of a strawberry extract (Fragaria × ananassa) by ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry. Anal. Bioanal. Chem. 2017, 409 (8), 2127–2142. Berendsen, B. J. A.; Wegh, R. S.; Meijer, T.; Nielen, M. W. F. The assessment of selectivity in different quadrupole-orbitrap mass spectrometry acquisition modes. J. Am. Soc. Mass Spectrom. 2015, 26 (2), 337–346. European Commission. Guidance document on analytical quality control and method validation procedures for pesticide residues and analysis in food and feed SANTE/11813/2017; 2017. Alañón, M. E.; Pérez-Coello, M. S.; Marina, M. L. Wine science in the metabolomics era. TrAC - Trends Anal. Chem. 2015, 74, 1–20. Donato, P.; Rigano, F.; Cacciola, F.; Schure, M.; Farnetti, S.; Russo, M.; Dugo, P.; Mondello, L. Comprehensive two-dimensional liquid chromatography–tandem mass spectrometry for the simultaneous determination of wine polyphenols and target contaminants. J. Chromatogr. A 2016, 1458, 54–62. ZHANG, X.; ZHENG, Y.; ZENG, Y.; LIU, W. Direct analysis of 38 polyphenols in wine by ultra high performance liquid chromatography-linear ion trap/orbitrap high resolution mass spectrometry. Chinese J. Chromatogr. 2015, 33 (6), 583. 26 ACS Paragon Plus Environment
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693
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Figure Captions:
694 695
Figure 1: Scores assigned to the investigated analytes based on the following rules : for range linearity
696
comparison, score 2 when R2 > 0.99, score 1 when R2 > 0.98, score 0 when R2 < 0.98; for LOQ
697
values comparison, score 1 and 0 assigned to the technique showing the lowest and highest LOQ
698
value, respectively; for ME comparison, score 3 if the deviation from 100% was < 10%, score 2 if
699
the deviation < 20%, score 0 if the deviation > 50; for intra-day precision comparison, score 2 when
700
RSD% < 5%, score 1 when RSD% < 10%, and score 0 when RSD% > 10%; for inter-day precision,
701
score 2 when RSD% < 10%, score 1 when RSD% < 20%, score 0 when RSD% > 20%.
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Journal of Agricultural and Food Chemistry
Table 1: The Compounds Analysed by Q-orbitrap-MS are Reported Together with Their Retention Time, Molecular Formula, Precursor Ion Mass and Fragment Ion Mass, both in Positive and Negative Polarity. Compounds
Tr
Molecular formula
Precursor ion [M+H]+
Product ion [M+H]+
Precursor ion [M-H]-
Product ion [M-H]-
apigenin
19.9
C15H10O5
271.0601
153.0181
269.0455
117.0336
apigenin glucoside
14.2
C21H20O10
433.1129
153.0183
431.0984
211.0397
biochanin A
26.8
C16H12O5
285.0758
213.0546
283.0612
211.0396
caffeic acid
3.5
C9H8O4
181.0496
89.0390
179.0350
135.0444
callistephin
6.9
C21H20O10
433.1129
121.0286
-
-
catechin
3.1
C15H14O6
291.0863
123.0442
289.0718
109.0285
catechin gallate
11.4
C22H18O10
443.0973
123.0443
441.0827
125.0235
chlorogenic acid
3.7
C16H18O9
355.1024
89.0390
353.0878
85.0284
cinnamic acid
14.2
C9H8O2
149.0597
103.0547
147.0451
90.9703
coumaric acid
7.8
C9H8O2
165.0546
91.0548
163.0401
119.0493
coumestrol
20.0
C15H8O5
269.0445
157.0647
267.0299
266.0225
cyanidin
6.9
C15H10O6
287.0550
121.0287
285.0405
116.7973
daidzein
15.7
C15H10O4
255.0652
91.0546
253.0506
91.0179
diosmetin
21.0
C16H12O6
301.0707
56.9654
299.0561
174.9558
epicatechin
6.2
C15H14O6
291.0863
123.0444
289.0718
109.0285
epicatechin gallate
10.5
C22H18O10
443.0973
123.0443
441.0827
125.0235
equol
18.9
C15H14O3
243.1016
105.0702
241.0870
68.9946
eriodictyol
15.7
C15H12O6
289.0707
153.0181
287.0561
135.0443
ferulic acid
7.9
C10H10O4
195.0652
89.0391
193.0506
133.0287
flavone
26.1
C15H10O2
223.0754
95.0495
-
-
formononetin
22.4
C16H12O4
269.0808
197.0595
267.0663
195.0447
gallic acid
0.7
C7H6O5
-
-
169.0142
125.0235
genistein
19.1
C15H10O5
271.0601
91.0546
269.0455
133.0287
genistin
11.8
C21H20O10
433.1129
91.0547
431.0984
211.0397
glycitein
16.9
C16H12O5
285.0758
242.0562
283.0612
211.0396
hesperetin
20.3
C16H14O6
303.0863
153.0181
301.0718
164.0110
hesperidin
14.9
C28H34O15
-
-
609.1825
301.0718
isorhamnetin
21.0
C16H12O7
317.0656
153.0181
315.0510
63.0229
kaempferol
20.1
C15H10O6
287.0550
153.0181
285.0405
93.0335
kuromanin
5.7
C21H20O11
449.1078
137.0236
447.0933
211.0396
luteolin
17.5
C15H10O6
287.0550
153.0181
285.0405
133.0287
luteolin glucoside
12.3
C21H20O11
449.1078
153.0184
447.0933
133.0287
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Journal of Agricultural and Food Chemistry
Page 30 of 35
malvidin
12.4
C17H15O7
331.0818
121.0288
330.0745
114.9507
malvidin galactoside morin
7.9
C23H25O12
493.1346
315.0498
492.1273
214.0269
15.4
C15H10O7
303.0499
121.0288
301.0354
125.0235
myricetin
13.7
C15H10O8
319.0448
153.0183
317.0303
109.0285
naringenin
18.6
C15H12O5
273.0758
153.0181
271.0612
119.0493
peonidin glucoside
8.0
C22H23O11
463.1240
201.0547
462.1168
227.0347
phloretin
19.8
C15H14O5
275.0914
107.0494
273.0768
81.0334
primuletin
30.6
C15H10O3
239.0703
137.0232
-
-
procyanidin B1
2.7
C30H26O12
579.1497
135.0440
577.1352
57.0334
procyanidin B2
5.6
C30H26O12
579.1497
123.0444
577.1352
57.0334
quercetin
17.2
C15H10O7
303.0499
153.0178
301.0354
174.9558
quercitin glucoside
11.9
C21H20O12
465.1028
153.0183
463.0882
271.0253
resveratrol
13.9
C14H12O3
229.0859
107.0495
227.0714
143.0494
rutin
11.8
C27H30O16
611.1607
153.0183
609.1461
271.0253
syringetin
21.1
C17H14O8
347.0761
153.0181
345.0616
203.0346
syringic acid
4.6
C9H10O5
199.0600
125.0235
197.0455
95.0128
taxifolin
9.1
C15H12O7
305.0656
123.0444
303.0510
57.0334
trihydroxyflavone
14.0
C15H10O5
271.0601
141.0699
269.0455
117.0336
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Journal of Agricultural and Food Chemistry
Table 2: The Compounds Analysed by QqQ-MS are Reported Together with Their Retention Time, Precursor Ion Mass, S Lens, Quantifier and Qualifier Transition, and the Corresponding Collision Energies, both in Positive and Negative Polarity Mode. Compound
Tr
Precursor S Product ion lens Ionsa + [M+H] (V) [M+H]+
Collision Energy (V)
Precursor S Product ion lens Ions [M-H](V) [M-H]-
apigenin
21
271
140
153.1 119.2
31 33
269.1
130
117.1 151.1
22 23
apigenin glucoside
15.4
433.1
120
271 153.1
19 46
431.1
183
268 269.1
36 27
biochanin a
27.9
285
140
213.0 269.0
39 30
282.9
110
267.9 239.0
23 35
caffeic acid
4
181
55
163.1 89.3
6 32
179
63
135 135
17 27
callistephin
8.2
433.1
131
271.1 121.5
29 53
431.1
155
269 267.9
20 27
catechin
3.6
291.1
100
250.1 139.1
7 14
289
117
245.1 203.1
16 17
catechin gallate
12.7
443.1
110
123.1 139.1
20 24
441.1
116
289 169
19 22
chlorogenic acid
4.7
355.1
150
267 73.3
22 28
353.1
80
191.1 85.1
15 38
cinnamic acid
15.4
149
90
65.4 93.3
25 19
147.1
61
103.2 77.2
12 24
coumaric acid
9
165
63
147.2 91.3
5 22
163
54
118.6 90.5
16 27
coumestrol
21
269
160
241.1 213.1
22 28
267
116
266 211
29 30
cyanidin
8.1
287
115
230.9 148.8
20 22
-
-
-
-
daidzein
16.9
255
170
199.1 137.1
24 27
253
130
208.1 224.1
31 28
diosmetin
22.2
301
110
286 258
27 37
299.1
120
284.1 227.1
21 37
epicatechin
7.2
291
110
139.1 123.2
18 23
289
115
245.1 203.1
15 19
epicatechin gallate
11.7
443.1
150
402 385.8
20 42
441
130
169.1 289.1
24 23
equol
20.0
242.9
90
165.0 135.0
12 22
241
77
121.0 119.1
16 22
eriodictyol
16.9
289.1
120
153.1 163.1
25 19
287.1
90
151.1 135.2
13 27
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Journal of Agricultural and Food Chemistry
Page 32 of 35
ferulic acid
9.2
195
67
177.1 145.1
10 17
193.1
73
134.1 178.2
15 14
flavone
27.2
223.1
115
77.3 121.2
34 25
-
-
-
-
269
139
197.1 253.1
40 30
267
110
251.9 223
22 33
formononeti 23.6 n gallic acid
0.7
-
-
-
-
169
60
125.2 124
17 14
genistein
20.3
271
120
153.1 91.3
27 36
269
107
133 132
34 45
genistin
13.1
433.1
110
271 153
20 48
431.1
152
268 266.8
29 45
glycitein
18.1
285
165
270.1 242.1
25 33
283
89
268 240
19 27
hesperetin
21.4
303.1
115
177.2 153.1
19 22
301.1
120
286.1 136.1
19 31
hesperidin
16.1
-
-
-
-
609.1
210
301.1 286
32 50
isorhamneti n
22.1
317
160
302 152.9
26 35
315
182
300 151.1
23 31
kaempferol
21.2
287
135
153.1 121.1
31 32
285.1
110
185.1 151.1
27 20
kuromanin
6.95
449.1
123
287 213.1
22 56
447
171
285.1 284.1
21 27
luteolin
18.7
287
150
153.1 135.2
32 33
285
125
133 132
37 52
luteolin glucoside
13.6
449.1
115
287 153
19 52
447.1
182
285 283.8
28 40
malvidin
14.8
331
200
315 287
31 32
-
-
-
-
malvidin galactoside
9.4
493.1
140
331 315
22 48
491.1
195
328.1 329.2
27 22
morin
16.5
303
145
153.1 229
28 25
301
117
151.1 125.1
21 22
myricetin
15
319
150
153 217.1
34 34
317.1
120
151.1 179
25 20
narigenin
19.8
273
115
153.1 147.1
26 22
271
110
119.2 151
25 19
peonidin glucoside
9.3
463.1
126
301 389.2
22 16
461.1
128
299 297.9
19 26
phloretin
21
275
95
107.2 169.1
19 14
273.1
97
167.1 123.2
17 24
primuletin
31.6
239
120
137.1 139.1
29 43
-
-
-
-
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Journal of Agricultural and Food Chemistry
procyanidin B1
3.6
579.1
140
409.1 427
19 14
577.1
160
289.2 407.1
34 25
procyanidin B2
6.8
579.1
145
427 290.9
15 14
577.1
154
407.1 425.2
25 16
quercetin
18.4
303
150
229 153.1
29 32
301
125
151 179
22 20
quercetin glucoside
13.2
465.1
110
303 153.1
15 49
463.1
140
300 301.1
29 23
resveratrol
15.1
229.1
100 `
107.2 135.2
21 14
227.1
100
185.1 143.2
19 26
rutin
13.2
611.1
115
303 465
21 11
609.1
190
300 271
40 60
syringetin
22.3
347.1
130
287 153.1
22 30
345
150
315 330.1
27 21
syringic acid
5.4
199
68
140.1 125.1
16 27
197
72
182.1 123.2
16 25
taxifolin
10.3
305
110
259 153.1
13 15
303.2
105
285.1 125
14 22
trihydroxyfl 15.3 avone
271
150
141.2 169.1
37 33
269.1
145
240.1 195.1
28 29
a) The product ion in bold is the highest product ion, chosen as the quantifier transition.
33 ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
Figure 1
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Journal of Agricultural and Food Chemistry
Graphic for table of contents
35 ACS Paragon Plus Environment