A “Brick Mass Spectrometer” Driven by a Sinusoidal Frequency

Apr 28, 2017 - Design of arbitrary waveform generator based on FPGA and Wi-Fi for miniature mass spectrometer. Dayu Li , Gongjie Zhang , Haoqiang Yan ...
0 downloads 0 Views 3MB Size
Download PDF
Article pubs.acs.org/ac

A “Brick Mass Spectrometer” Driven by a Sinusoidal Frequency Scanning Technique Ting Jiang,†,# Hongjia Zhang,‡,# Yang Tang,† Yanbing Zhai,† Wei Xu,† Hualei Xu,† Xinying Zhao,§ Dayu Li,*,‡ and Wei Xu*,† †

State Key Laboratory of Explosion Science and Technology, School of Life Science, Beijing Institute of Technology, Beijing 100081, China ‡ School of Computer Science and Engineering, Northeastern University, Shenyang, 110819, China § Beijing Center Physical and Chemical Analysis, Beijing, 100089, China S Supporting Information *

ABSTRACT: In this work, a “brick” size miniature mass spectrometer (28 cm × 21 cm × 16 cm) was developed and characterized, which was enabled by the development of a new frequency scanning technique. Different from the conventional voltage scanning method or the digital waveforms used on a digital ion trap, a sinusoidal frequency scanning technique was developed to drive the linear ion trap of the brick mass spectrometer (BMS). Both an in-vacuum plasma ionization source and an electrospray ionization source were coupled with this BMS for the analyses of volatile and nonvolatile samples. Stability diagram, sensitivity, mass resolution, and mass range of the BMS were explored. This new frequency scanning technique could not only reduce the size and power consumption of a miniature mass spectrometer but also improve its analytical performances, especially in terms of mass range and resolution. Analogous to the development of cell phones, this BMS would be an important step from “brick” mass spectrometer to “cell” mass spectrometer.

W

the vacuum while allowing volatile organic compound (VOC) molecules to be sampled.17−22 Both discontinuous atmospheric pressure interface (DAPI)2,10,23−26 and continuous atmospheric pressure interface (CAPI)27,28 have been developed, which enable the analyses of liquid- and solid-phase samples using miniature mass spectrometers.2,25,29−31 It has been shown that an ion trap could work at a pressure as high as 1 Torr, which would potentially lead to a miniature mass spectrometer without the need of a turbo pump.32 With the emergence of smaller vacuum systems, electronic system becomes a prominent part in a miniature MS system, especially for a quadrupole mass analyzer. There are basically two operating modes to drive an ion trap: the voltage scanning mode and the frequency scanning mode.33 In voltage scanning mode, mass analysis of an ion trap was performed by linearly ramping the amplitude of a single frequency rf signal. In this way, a high rf voltage (thousands of volts) is required to cover ions with higher mass to charge (m/z) ratios. In the frequency scanning mode, a digital ion trap34−37 was driven by a square wave, which has a constant amplitude (typical around hundreds of volts), and mass analysis was performed by linearly scanning period of the square waveform (or frequency scanning the

ith the increasing public concerns about health and environmental issues, there are growing demands for biochemical analyses in modern society. With high sensitivity and broad coverage range, miniaturized, and portable mass spectrometers would satisfy the needs of many on-site and personalized applications.1−3 However, mass spectrometry (MS) instruments are typically large in size and delicate in operation. With great efforts, significant progresses have been made on the developments of miniature mass spectrometers, especially over the past decade.1,3−8 Portable mass spectrometers have been developed.3,9−12 Compared to the development of personal computing devices, such as personal computers and cell phones, current miniature mass spectrometers are probably in the stage of benchtop devices. More efforts are still needed to improve its analytical performances, portability and usability, before it is ready to be widely used. MS miniaturization is a systematic problem. Vacuum system, electronic system, mass analyzer, and even the detector are correlated and all have direct impacts on instrument miniaturization. In an effort to lower the required radio frequency (rf) voltage, miniaturized or even micrometer-sized quadrupole ion traps and quadrupole rods have been fabricated using techniques such as microelectromechanical system (MEMS) and advanced laser fabrication techniques.13−16 On the other hand, atmosphere-vacuum interface is the key to design a small vacuum system while maintaining effective samplings. For example, membrane inlets could effectively hold © XXXX American Chemical Society

Received: February 26, 2017 Accepted: April 20, 2017

A

DOI: 10.1021/acs.analchem.7b00719 Anal. Chem. XXXX, XXX, XXX−XXX

Article

Analytical Chemistry principle frequency of the square waveform). A miniature mass spectrometer typically adopts the voltage scanning mode, since the power consumption of the frequency scanning square wave is much higher than that of the voltage scanning sinusoidal wave. The technique of scanning frequency of the AC signal for ion resonance ejection was also used as an alternative method to simplify the driving circuit.38−41 In this work, a miniature mass spectrometer was developed based on a new frequency scanning method. Close to the size of a brick (28 cm × 21 cm × 16 cm), it is named as “brick mass spectrometer” (BMS). Vacuum system of this BMS was designed based on the CAPI technique developed in our group earlier.27,28 A new electronic system based on sinusoidal frequency scanning technique was developed to drive the ion trap. Different from the square waveform, pure sinusoidal waveform was generated with its frequency scanned from 1 MHz to 200 kHz and a constant voltage of 600 Vp−p. Small-insize and low-in-power consumption, this new rf scanning method and the corresponding electric circuit were characterized through theory and experiments. Both in-vacuum plasma ionization and electrospray ionization sources were coupled with the BMS to characterize its sensitivity, resolution and mass range.

As studied earlier, the presence of buffer gas will shift the stability diagram.45−48 In the conventional voltage scanning mode, b is a constant and the stability diagram does not change during the scan process. However, since b is rf frequency dependent, the stability diagram will also shift during the rf scanning process in the frequency scanning mode. Using the Matrix Method,49 Figure 1 plots some typical stability diagrams

Figure 1. First stability region of a linear ion trap with different damping coefficients.

■

THEORY Frequency-Dependent Stability Diagram. The stability diagram is one of the most important features of an ion trap. Conventionally, the stability diagram of an ion trap is believed to be unchanged, which is true if the ion trap is driven in the voltage scanning mode. In the frequency scanning mode, the stability diagram is actually frequency-dependent, especially at high buffer gas pressures. With the presence of buffer gases, the motion of a trapped ion in a linear ion trap can be described as42,43 d2u du 2z +c =− [U + V cos(Ωt )]u 2 dt dt mr0 2

with different b values. With increased buffer gas pressure or lowered rf frequency, an enlarged stability diagram is expected. In the frequency scanning mode, the rf frequency is typically scanned from a higher frequency to a lower frequency. As a typical scenario in this work (buffer gas pressure 6 mTorr, air), the b value would change from 0.0044 to 0.011 as the rf frequency scanned from 1 MHz to 400 kHz for an ion with a mass of 100 Da (+1 charge). As shown in Figure 1, the effect of stability diagram shifting during the rf scanning process could be neglected. However, at a higher buffer gas pressure, 100 mTorr for instance, the b value would change from 0.073 to 0.183 as the rf frequency scanned from 1 MHz to 400 kHz for the same ion (mass 100 Da, +1 charge). In this case, this frequency-dependent stability diagram shifting effect needs to be taken into account during the mass calibration process. On the other hand, a higher rf frequency could also be used minimize this effect by reducing the absolute value of this b parameter.

(1)

where u stands for one of the ion motion direction x or y, U and V are the DC and AC potentials applied to the x or y pair of electrodes, Ω is rf frequency, m is the ion mass, z is the charge an ion possess, r0 is the radius of the ion trap, and c is the damping factor because of ion-neutral collisions (the estimation of c can be found in the Supporting Information). Substituting ξ = Ωt/2, and eq 1 becomes

■

INSTRUMENTATION Design of the BMS could be found in Figure 2a. There are three major parts in the BMS, namely, the electronic system, the vacuum system, and the ion trap assemble. The vacuum system of the BMS was designed based on the continuous atmospheric pressure interface, in which a dual stage vacuum chamber was used and a pinhole (diameter 0.3 mm) was used to connect these two vacuum stages. A linear ion trap (LIT) with hyperbolic electrodes and dimensions of 4 × 4 mm (center to the electrode distance) and 40 mm (length) was used as the mass analyzer. Detailed information about the vacuum system could be found in our previous publications.27 This BMS adopt a modular design philosophy to minimize instrument dimension, as well as to make it easy to work with. As shown in Figure 2a, vacuum pumps, including the turbo pump (Hipace 10, Pfeiffer Inc. Germany) and the scroll pump (SVF-E0-50, Scroll Tech. Inc., China), were located on one side of the instrument. The vacuum chamber and the control electronics were placed on the other side of the instrument.

2

du du + 2b + [au − 2qu cos(2ξ)]u = 0 2 dξ dξ

(2)

with the parameters defined as ax = −ay =

8eU , mΩ2r0 2

qx = −qy =

4eV , mΩ2r0 2

b=

c Ω (3)

By introducing the following variable u′

44

u = e(−bt )u′

(4)

Equation 2 becomes the reduced Mathieu’s equation d2u′ + [au − b2 − 2qu cos(2ξ)]u′ = 0 2 dξ

(5)

This equation has the identical form as the traditional Mathieu equation, except that the parameter au was shifted by b2.45 B

DOI: 10.1021/acs.analchem.7b00719 Anal. Chem. XXXX, XXX, XXX−XXX

Article

Analytical Chemistry

Figure 2. (a) 3D assembly of the BMS. (b) Schematic of the electronic system of the BMS. (c) Photos of each part of the electronic system. A: Mini waveform generator. B: End-cap DC module. C: DC power supply board. D: Central control system (CCS). E: Signal amplifier. F: Broadband rf amplifier.

Co., Ltd., China). Ion signals collected by the detector was then amplified by a signal amplifier (Figure 2c.E) and fed back into the CCS. A user interface program coded in C# language was developed to control the electronic systems running on a Microsoft Windows 7 computer. The CCS communicates with the laptop via a UART port. Characterization of the Broadband rf Amplifier. Besides output voltage and frequency, power consumption and total dimension are two important features of an rf amplification module, especially for the development of a miniature mass spectrometer. Table 1 compares three different

With an integrated design, the whole BMS system has total dimensions of 28 cm in length, 21 cm in width, and 16 cm in height. Control Electronics. Schematic of the control electronics is shown in Figure 2b. The central control system (CCS, Figure 2c.D) serves as the brain of the instrument, on which ARM core microcontroller (TM4C123GH6PM, Texas Instruments, Inc., TX, USA) was programmed to perform signal generation and data acquisition. This CCS will communicate with other boards and synchronize the timing of rf, AC, and DC signals. The rf signal was generated by a mini waveform generator and amplified (Figure 2c.A) by the broadband rf amplifier (Figure 2c.F). The mini waveform generator could provide an output signal with a frequency up to 25 MHz and amplitude up to 10 Vp‑p, which was constructed with a programmable frequency sweep waveform chip (AD5930, Analog Devices, Inc. MA, USA) and a prime amplifier. Packaged by the 3-D printing technique, the broadband rf amplifier is small-in-size (3.8 cm both in width and height and 10 cm in length) and light-inweight (∼93 g). There are two amplification stages in the broadband rf amplifier, which are the solid state amplification stage and the voltage transformer amplification stage. An air cooling fan was also integrated in the package for temperature control. As a result, it can amplify a broadband rf signal from 1 MHz to 200 kHz with an amplification factor of 60, and the maximum output voltage is 600 Vp‑p. Another mini waveform generator was used to generate the resonance ejection AC signal. An end-cap DC module (Figure 2c.B) was used to provide the DC voltages (0−120 V) applied on the end-caps of the ion trap, and a DC power supply board (Figure 2c.C) was constructed to feed the 120 V to the end-cap DC module. The high DC voltage (0 to −2000 V) required to operate the detector (electron multiplier) was generated by a high voltage DC module (Tianjin Dongwen High voltage Power Supply

Table 1. Comparison of Three Different Types of rf Amplifiers

rf amplification modules in terms of these parameters. Besides the rf module developed in this work, a rectangular waveform rf amplifier used to drive a digital ion trap (Shimadzu, Inc., Shanghai, China) and a voltage scanning rf amplifier used in a miniature mass spectrometer27,28 were tested and compared. As shown in Table 1, this broadband rf amplifier has similar output characteristics (amplitude and frequency coverage range) as those of the rectangular waveform rf amplifier, however, with C

DOI: 10.1021/acs.analchem.7b00719 Anal. Chem. XXXX, XXX, XXX−XXX

Article

Analytical Chemistry

Figure 3. (a) MS scan function of the sinusoidal frequency scanning mode. (b) Mass calibration curve corresponding to the linear frequency scanning mode. Inset: rf and AC frequency scanning curves.

much smaller power consumption and dimension. Basically two reasons would contribute to this low power consumption. First, a sinusoidal waveform is more power efficient in a theoretical point of view. The active power of a sinusoidal waveform is proportional to 0.79 V2 (V is the amplitude of the waveform), while a rectangular waveform is proportional to V2. When these two circuits are having the same output amplitude, a rectangular waveform would at least consume 1.27 times the power of a sinusoidal waveform, theoretically. When these two circuits are providing the same pseudopotential well depth, a rectangular waveform would consume at least 0.77 times the power of a sinusoidal waveform (the pseudopotential well depth is 0.25qV for a sinusoidal waveform and 0.412qV for a rectangular waveform).36 On the other hand, a power-efficient amplifier is also much easier to be realized for a sinusoidal waveform generator. A sinusoidal waveform could use low-power voltage amplification techniques such as resonance and voltage transformers; while a rectangular waveform generation circuit might also suffer from high power lost due to the instantaneous voltage switching. As a result, the broadband rf amplifier designed in this work has similar voltage output and frequency coverage, but has much less power consumption (∼22 W) than the rectangular waveform rf amplifier used in a digital ion trap (∼120 W). With comparable power consumption (22 and 18 W), the broadband rf amplifier is also smaller than the conventional voltage scanning rf amplifier. Shown later in this work, the broadband rf amplifier could also cover a much wider mass range using frequency scanning technique. There are two key differences between this BMS and similar mini-MS systems, such as the mini 11 developed by Purdue University.50 The first difference is the rf driving method, and the second difference is the atmospheric pressure interface. Mini 11 uses a discontinuous atmospheric pressure interface and its ion trap is driven by the voltage scanning method. As a result, this BMS system has a smaller electronic system, but a relatively larger vacuum pumping system, since the scroll pump used in this work is larger in size and higher in power consumption. These two systems have similar mass range, sensitivity and dimensions. Mini 11 has lower power consumption, and the BMS in this work has a faster mass scan rate and improved stability. Sample Preparation. Naphthalene (MW 128.17), 1,2,4trichlorobenzene (MW 181.45), and methyl salicylate (MW 152.15) were purchased from Acros Organics (New Jersey, USA), acetophenone (MW 120.14), and N,N-diethyl-3methylbenzamide (DEET, MW 191.27) were purchased from TCI (Shanghai) Development Co., Ltd. (Shanghai, China). Polyethylene glycol (PEG) 600 and PEG 1500 were purchased

from Sigma-Aldrich (St. Louis, MO, USA). All chemicals were shipped as a solution with a purity of about 99%, except for naphthalene as solid. All samples were analyzed in vapor gases except for PEG 600 and PEG 1500, which were diluted in methanol−water (1:1 v/v). All experiments were completed in a laboratory with a room temperature of 25 °C.

■

RESULTS AND DISCUSSIONS Scan Function. Similar to the amplitude scanning mode, the scan function in this frequency scanning mode also has four periods: ionization, cooling, MS scan and empty as shown in Figure 3a. The four periods last 10, 10, 100, and 10 ms, respectively. In this study, the highest voltage of the end-caps was fixed at 100 V, and the detector voltage was fixed at −1500 V. In the ionization and cooling periods, the amplitude and frequency of the rf waveform were kept constant for ion trapping. During the scan period, amplitude of the rf and AC waveforms were keep constant, while their frequencies were swept from high to low. The rf frequency was swept linearly from 1 MHz to 400 kHz within 100 ms with an amplitude of 309 Vp‑p, and the AC frequency was swept linearly from 400 kHz to 160 kHz with an amplitude of 3 Vp‑p (Figure 3b inset). In this way, a resonance ejection point of qeject = 0.86 was realized for ion ejection. Mass Calibration. The linear rf and AC frequency scan actually results in a nonlinear correlation between m/z ratio and ion ejection time. Fortunately, a calibration procedure has been developed and reported for secular frequency scanning in ion trap mass spectrometers.51 Following a similar procedure, a simplified mass calibration approach was performed using Matlab (MathWorks, Inc., MA, USA) in this study. Ion secular frequency in an ion trap is given by ωu ,0 = βu Ω/2

(6)

where βu is a function of au and qu. The relation between βu and qu can be approximately expressed as44 βu =

⎡ 2 −1⎢ π sin ⎢2 π ⎣

⎤ ⎛ 25 π2 ⎞ 4 ⎥ +⎜ − ⎟qu ⎥ 2 48 ⎠ ⎦ ⎝ 128

qu 2

(7)

in which the quadrupole DC voltage was set at 0 and au = 0. The mass calibration process has several steps. First, each rf and AC frequency during the MS scan process need to be correlated with each data point collected in time. These frequencies are subsequently converted into βu (eq 6), and then to qu by solving eq 7. Since the relationship between qu and m/z D

DOI: 10.1021/acs.analchem.7b00719 Anal. Chem. XXXX, XXX, XXX−XXX

Article

Analytical Chemistry

Figure 4. Mass spectra of some typical chemicals using the in-vacuum plasma ionization source. (a) Methyl salicylate (m/z 153 Th), (b) DEET (m/z 192 Th), (c) acetophenone (m/z 121 Th), and (d) mixture of naphthalene (m/z 128 Th) and 1,2,4-trichlorobenzene (m/z 180 Th).

is known (eq 3), finally a correlation between ion ejection time and m/z ratio could be established as shown in Figure 3b. Figure 4 shows some typical mass spectra collected from this BMS when using the in-vacuum plasma ionization source. Protonated ions, as well as some fragment ions, could be observed for methyl salicylate (m/z 153, Figure 4a), DEET (m/ z 192, Figure 4b), acetophenone (m/z 121, Figure 4c), and a mixture of naphthalene (m/z 128) and 1,2,4-trichlorobenzene (m/z 180) (Figure 4d). In these experiments, vials containing the solid- or liquid-phase chemicals were opened and placed below the inlet of the mass spectrometer. As discussed previously,28 ion fragmentation are related to the temperature and power of the plasma ionization source. Limit of Detection. Sensitivity of the instrument was characterized using the in-vacuum plasma ionization source and the headspace vapor technique. As shown in Figure 5a, volatile samples were prepared in 500 mL glass sampling bottles sealed with rubber plugs for hours to achieve saturated headspace pressure. A syringe was then used to extract the saturated gas from these bottles and then pumped into the mass spectrometer through a PFA tube (1/4 in. outer diameter, ∼1 m in length). During the transfer period in the PFA tube, analytes were diluted by air initiated by the pumping system of the mass spectrometer. Details about this quantitation method could be found in our previous work.28 Figure 5b plots the linear range of detection for naphthalene using the BMS. As shown in Figure 5b, a LOD of 20 ppbv was obtained, and a good linearity (R 2 > 0.99) was achieved within the concentration range from 20 ppbv to 1.9 ppmv. Mass Resolution. Mass resolution of an ion trap is affected by the buffer gas pressure in the ion trap. In the BMS developed in this work, pressure in the second vacuum stage, where the LIT was placed, is relatively high (∼6 mTorr). The presence of high-pressure background gas could help cooling ions to the center of the ion trap, but at the same time, it would also broaden the mass peak.52,53 To improve the mass resolution, frequency scan rate of the sinusoidal waveform during MS analysis could be tuned. Effects of frequency scan

Figure 5. Sensitivity of the BMS. (a) Instrumental setup for quantification analysis of gaseous samples and (b) linear range of detection for naphthalene.

rate on the mass resolution, as well as ion intensity, were examined. As shown in Figure 6a, mass resolution (full width at half-maximum, fwhm) could be improved with decreased frequency scan rate. At a frequency scan rate of 1200 kHz/s, a 0.2 Th fwhm of naphthalene could be achieved. However, ion intensity will be reduced if the scan rate is too low (Figure 6b), which might be due to the ion loss during the ion ejection process. Therefore, frequency scan rate needs to be optimized to achieve a balance between mass resolution and sensitivity. In the current BMS setup, a scan rate of 6000 kHz/s could be used as the optimized value, and a mass resolution of 0.5 Th could be obtained at m/z 128 Th. Besides the lowered rf scan rate, the frequency scanning method could potentially improve the mass resolution by working at higher rf frequencies (deeper potential well depth),42 especially for low mass ions. However, E

DOI: 10.1021/acs.analchem.7b00719 Anal. Chem. XXXX, XXX, XXX−XXX

Article

Analytical Chemistry

Figure 6. Mass resolution of the BMS. (a) MS resolution of the BMS with different scan rates. (b) The corresponding MS intensity of the BMS with different scan rates. Naphthalene was tested in experiments.

Figure 7. Mass range of the BMS. (a) Mass spectrum of PEG 600 (1000 μg/mL), rf signal frequency scanning from 1 MHz to 400 kHz with an amplitude of 460 Vp−p. (b) Mass spectrum of PEG 1500 (1000 ug/mL). rf signal frequency scanning from 500 kHz to 200 kHz with an amplitude of 520 Vp−p.

resolution could be achieved using this frequency scan method, while keeping similar working conditions, such as using the same ion trap and the same buffer gas condition.

further developments are needed in terms of developing rf amplifiers that could work at higher rf frequencies. Mass Range. Compared to the conventional voltage scanning method, mass range of an ion trap driven by the frequency scanning method could be easily extended. In the voltage scanning method, the mass range was limited by the rf voltage, especially the highest voltage that could be achieved. In the frequency scanning method, the mass range could be extended by the frequency scanning range and the rf voltage. To explore the mass range of the instrument, this BMS was coupled with a nanoelectrospray ionization (nanoESI). To switch from in-vacuum ionization source to nanoESI, we first turn off the high-voltage applied on the ring electrode of the invauum ionization source, and then placed the capillary closer (∼5 mm) to the pinhole on the vacuum chamber for enhanced ion transfer. Figure 7a shows the mass spectrum of PEG 600 (1000 ug/mL) by scanning the rf signal from 1 MHz to 400 kHz with an amplitude of 460 Vp−p. The mass range could be easily extended by either increasing the rf voltage or lowing the scanning frequency, or both. As shown in Figure 7b, PEG 1500 (1000 μg/mL) was analyzed by increasing this rf voltage to 520 Vp−p and scanning the rf frequency from 500 kHz to 200 kHz during the MS analysis period. In this case, a 3 V0−p AC signal with frequency scanned from 200 kHz to 80 kHz was used as the resonance ejection signal. Compared with the voltage scanning method,27 broader mass range and improved mass

■

CONCLUSION

In this work, a “brick” size miniature mass spectrometer driven by a new frequency scanning technique was developed and characterized. A low-power, small, broadband rf amplifier was developed to generate the frequency scanning sinusoidal waveforms used to drive the linear ion trap. It was found that an ion trap driven by the frequency scanning technique would have a frequency-dependent stability diagram, and a nonlinear mass calibration curve was obtained for the linear frequency scanning method. Analytical performances of the BMS were also explored in terms of limit of detection, mass resolution, and mass range. Small-in-size, capable of analyzing both gasphase and liquid-phase samples, this BMS could potentially be applicable in many on-site applications and would be an important step toward the development of “cell” size mass spectrometers. Furthermore, this new sinusoidal waveform generation method would enable new operation modes of ion traps and quadrupole rods, which are not limited to miniature mass spectrometers. F

DOI: 10.1021/acs.analchem.7b00719 Anal. Chem. XXXX, XXX, XXX−XXX

Article

Analytical Chemistry

■

(20) Frandsen, H.; Janfelt, C.; Lauritsen, F. R. Rapid Commun. Mass Spectrom. 2007, 21, 1574−1578. (21) Janfelt, C.; Graesboll, R.; Lauritsen, F. R. Int. J. Mass Spectrom. 2008, 276, 17−23. (22) Gao, L.; Song, Q.; Patterson, G. E.; Cooks, R. G.; Ouyang, Z. Anal. Chem. 2006, 78, 5994−6002. (23) Gao, L.; Cooks, R. G.; Ouyang, Z. Anal. Chem. 2008, 80, 4026− 4032. (24) Xu, W.; Charipar, N.; Kirleis, M. A.; Xia, Y.; Ouyang, Z. Anal. Chem. 2010, 82, 6584−6592. (25) He, M.; Xue, Z.; Zhang, Y.; Huang, Z.; Fang, X.; Qu, F.; Ouyang, Z.; Xu, W. Anal. Chem. 2015, 87, 2236−2241. (26) Wei, Y.; Bian, C.; Ouyang, Z.; Xu, W. Rapid Commun. Mass Spectrom. 2015, 29, 701−706. (27) Zhai, Y.; Feng, Y.; Wei, Y.; Wang, Y.; Xu, W. Analyst 2015, 140, 3406−3414. (28) Zhai, Y.; Jiang, T.; Huang, G.; Wei, Y.; Xu, W. Analyst 2016, 141, 5404−5411. (29) Huang, G.; Xu, W.; Visbal-Onufrak, M. A.; Ouyang, Z.; Cooks, R. G. Analyst 2010, 135, 705−711. (30) Sanders, N. L.; Kothari, S.; Huang, G.; Salazar, G.; Cooks, R. G. Anal. Chem. 2010, 82, 5313−5316. (31) Sokol, E.; Noll, R. J.; Cooks, R. G.; Beegle, L. W.; Kim, H. I.; Kanik, I. Int. J. Mass Spectrom. 2011, 306, 187−195. (32) Blakeman, K. H.; Wolfe, D. W.; Cavanaugh, C. A.; Ramsey, J. M. Anal. Chem. 2016, 88, 5378−5384. (33) March, R. E.; Hughes, R. J. Quadrupole Storage Mass Spectrometry; Wiley: New York, 1989. (34) Ding, L.; Brancia, F. L. Anal. Chem. 2006, 78, 1995−2000. (35) Ding, L.; Kumashiro, S. Rapid Commun. Mass Spectrom. 2006, 20, 3−8. (36) Ding, L.; Sudakov, M.; Brancia, F. L.; Giles, R.; Kumashiro, S. J. Mass Spectrom. 2004, 39, 471−484. (37) Ding, L.; Sudakov, M.; Kumashiro, S. Int. J. Mass Spectrom. 2002, 221, 117−138. (38) Huang, G.; Gao, L.; Duncan, J.; Harper, J. D.; Sanders, N. L.; Ouyang, Z.; Cooks, R. G. J. Am. Soc. Mass Spectrom. 2010, 21, 132− 135. (39) Snyder, D. T.; Pulliam, C. J.; Cooks, R. G. Rapid Commun. Mass Spectrom. 2016, 30, 2369−2378. (40) Snyder, D. T.; Pulliam, C. J.; Cooks, R. G. Rapid Commun. Mass Spectrom. 2016, 30, 800−804. (41) Snyder, D. T.; Pulliam, C. J.; Wiley, J. S.; Duncan, J.; Cooks, R. G. J. Am. Soc. Mass Spectrom. 2016, 27, 1243−1255. (42) March, R. E.; Todd, J. F. Quadrupole Ion Trap Mass Spectrometry; 2nd ed.; Wiley: Hoboken, NJ, 2005. (43) Dawson, P. H. Quadrupole Mass Spectrometry and Its Applications; American Institute of Physics: College Park, MD, 1995. (44) Hasegawa, T.; Uehara, K. Appl. Phys. B: Lasers Opt. 1995, 61, 159−163. (45) Whitten, W. B.; Reilly, P. T.; Ramsey, J. M. Rapid Commun. Mass Spectrom. 2004, 18, 1749−1752. (46) Kiai, S. S.; Chaharborj, S. S.; Bakar, M. A.; Fudziah, I. J. Anal. At. Spectrom. 2011, 26, 2247−2256. (47) Seddighi Chaharborj, S.; Phang, P.; Sadat Kiai, S.; Majid, Z.; Abu Bakar, M. R.; Fudziah, I. Rapid Commun. Mass Spectrom. 2012, 26, 1481−1487. (48) Ziaeian, I.; Noshad, H. Int. J. Mass Spectrom. 2010, 289, 1−5. (49) Konenkov, N.; Sudakov, M.; Douglas, D. J. Am. Soc. Mass Spectrom. 2002, 13, 597−613. (50) Gao, L.; Sugiarto, A.; Harper, J. D.; Cooks, R. G.; Ouyang, Z. Anal. Chem. 2008, 80, 7198−7205. (51) Snyder, D. T.; Pulliam, C. J.; Cooks, R. G. Rapid Commun. Mass Spectrom. 2016, 30, 1190−1196. (52) Goeringer, D. E.; Whitten, W. B.; Ramsey, J. M.; McLuckey, S. A.; Glish, G. L. Anal. Chem. 1992, 64, 1434−1439. (53) Xu, W.; Song, Q.; Smith, S. A.; Chappell, W. J.; Ouyang, Z. J. Am. Soc. Mass Spectrom. 2009, 20, 2144−2153.

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.analchem.7b00719. Estimation of the damping factor (PDF)

■

AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]. *E-mail: [email protected]. ORCID

Wei Xu: 0000-0001-5274-1546 Author Contributions #

T.J. and H.Z. contributed equally.

Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS This work was supported by MOST instrumentation program of China (2012YQ040140-07), NSF (21475010), BNSF (16L00065), and State Key Laboratory Explosion Science and Technology (YBKT16-17).

■

REFERENCES

(1) Ouyang, Z.; Cooks, R. G. Annu. Rev. Anal. Chem. 2009, 2, 187− 214. (2) Li, L.; Chen, T.-C.; Ren, Y.; Hendricks, P. I.; Cooks, R. G.; Ouyang, Z. Anal. Chem. 2014, 86, 2909−2916. (3) Snyder, D. T.; Pulliam, C. J.; Ouyang, Z.; Cooks, R. G. Anal. Chem. 2016, 88, 2−29. (4) Kornienko, O.; Reilly, P. T.; Whitten, W. B.; Ramsey, J. M. Rapid Commun. Mass Spectrom. 1999, 13, 50−53. (5) Meuzelaar, H. L.; Dworzanski, J. P.; Arnold, N. S.; McClennen, W. H.; Wager, D. J. Field Anal. Chem. Technol. 2000, 4, 3−13. (6) Lammert, S. A.; Plass, W. R.; Thompson, C. V.; Wise, M. B. Int. J. Mass Spectrom. 2001, 212, 25−40. (7) Lammert, S. A.; Rockwood, A. A.; Wang, M.; Lee, M. L.; Lee, E. D.; Tolley, S. E.; Oliphant, J. R.; Jones, J. L.; Waite, R. W. J. Am. Soc. Mass Spectrom. 2006, 17, 916−922. (8) Austin, D. E.; Peng, Y.; Hansen, B. J.; Miller, I. W.; Rockwood, A. L.; Hawkins, A. R.; Tolley, S. E. J. Am. Soc. Mass Spectrom. 2008, 19, 1435−1441. (9) Yang, M.; Kim, T.-Y.; Hwang, H.-C.; Yi, S.-K.; Kim, D.-H. J. Am. Soc. Mass Spectrom. 2008, 19, 1442−1448. (10) Wiley, J. S.; Shelley, J. T.; Cooks, R. G. Anal. Chem. 2013, 85, 6545−6552. (11) Hemond, H. F. Rev. Sci. Instrum. 1991, 62, 1420−1425. (12) Xue, B.; Sun, L.; Huang, Z.; Gao, W.; Fan, R.; Cheng, P.; Ding, L.; Ma, L.; Zhou, Z. Analyst 2016, 141, 5535−5542. (13) Geear, M.; Syms, R. R.; Wright, S.; Holmes, A. S. J. Microelectromech. Syst. 2005, 14, 1156−1166. (14) Pau, S.; Pai, C.; Low, Y.; Moxom, J.; Reilly, P.; Whitten, W. B.; Ramsey, J. M. Phys. Rev. Lett. 2006, 96, 120801. (15) Austin, D. E.; Wang, M.; Tolley, S. E.; Maas, J. D.; Hawkins, A. R.; Rockwood, A. L.; Tolley, H. D.; Lee, E. D.; Lee, M. L. Anal. Chem. 2007, 79, 2927−2932. (16) Hauschild, J.-P.; Wapelhorst, E.; Müller, J. Int. J. Mass Spectrom. 2007, 264, 53−60. (17) Johnson, R.; Cooks, R.; Allen, T.; Cisper, M.; Hemberger, P. Mass Spectrom. Rev. 2000, 19, 1−37. (18) Ketola, R. A.; Kotiaho, T.; Cisper, M. E.; Allen, T. M. J. Mass Spectrom. 2002, 37, 457−476. (19) Janfelt, C.; Frandsen, H.; Lauritsen, F. R. Rapid Commun. Mass Spectrom. 2006, 20, 1441−1446. G

DOI: 10.1021/acs.analchem.7b00719 Anal. Chem. XXXX, XXX, XXX−XXX