本研究開發了一種非侵入性的人體皮膚表面採樣，降低了人體代謝採樣後處 理步驟的複雜度，提供一個簡單方便，可以快速量測的一個方法，成功結合採樣 與質譜進樣的方法。毛筆總重為 1.80 g，長為 17.7 cm。毛筆一次可吸附的乙醇 量為 6 mg，經過 27 分鐘後會完全揮發完畢，但是前四分鐘揮發速率較快，因此 實驗於 3 分鐘內會結束。接下來對於毛筆與質譜入口的距離做測試，以相同濃度 與同樣參數條件之下進行位置移動，觀察不同位置的訊號強度變化情形，發現水 平距離質譜口 1.5 mm 及垂直距離質譜口 3 mm 的位置，有最好的訊號條件。
本研究使用於 ESI-MS 分析的新型採樣方法的開發。利用水彩筆，可以通過 刷取受試者的眼皮或簡單地將分析物的溶液滴至毛筆上或者僅僅將毛筆浸入分 析物的溶液中來收集分析物。本實驗利用咖啡因當人體藥物代謝測試藥品，使用 本研究所開發的方法，證實此採樣方法的可行性。觀察不同受試者對咖啡因的代 謝，每個人對咖啡因代謝能力有所不同，但是早上的代謝能力都優於下午及晚上，
晚上則是代謝能力最緩慢的。運用此方法進行採樣分析簡單、經濟實惠、非侵入 性，最低可採樣到約 6μg 的咖啡因含量，適用於監測受試者長時間產生的代謝產 物。
47
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茲 證 明
完 成 國 立 臺 灣 師 範 大 學 研 究 倫 理 中 心 之 2 小時研究倫 理 線 上 教 育 訓 練 課 程 ( 含 學 習 測 驗 及 格 0.5 小時)。
張 凱 茵 君
研 習 證 明
Certificate of Attendance
We hereby certificate that Kai-Yin Chang
has completed the 2-hour Research Ethics On-Line Training Course of Center for Research Ethics, National Taiwan Normal University
on 2/8/2017.
國立臺灣師範大學 研究倫理中心主任
Director of Center for Research Ethics, NTNU
中 華 民 國 一 O 六 年 二 月 八 日 中 華 民 國 106 年 2 月 8 日
N o . 6 7
主 題 講 者
國立臺灣師範大學健康促進與衛生教育學系 暨研究倫理審查委員會主任委員
李思賢特聘教授 社 會 與 行 為 科 學 的 研 究 倫 理 與
貝 蒙 報 告
55
期刊論文
1. Development and Application of a Brush-Spray Derived from a Calligraphy-Brush-Style Synthetic Hair Pen for Use in ESI/MS
Jen-Ying Liu, Pei-Chun Chen, Yea-Wenn Liou, Kai-Yin Chang, and Cheng-Huang Lin*
2. 毛筆尖電噴灑質譜法的開發與應用
劉人瑛 張凱茵 劉亞汶 陳姵君 林震煌*
3. Sampling and Profiling Caffeine and its Metabolites from an Eyelid using a Watercolor Pen based on Electrospray Ionization/Mass Spectrometry
Yea-Wenn Liou, Kai-Yin Chang, Sing-Han Wang and Cheng-Huang Lin*
投稿中
56
研究發表
研究發表 : 2016 美國化學會台灣分會研究生研討會
發表題目：Development and application of a brush-spray/mass spectrometry
Kai-Yin Chang (張凱茵), Jen-Ying Liu (劉人瑛), Cheng-Huang Lin (林震煌)*
時間 : 105 年 5 月 29 日 (日) 地點 : 國立台灣大學化學館
研究發表 : 第二十三屆分析技術交流研討會
發表題目：Sampling and Profiling Caffeine and its Metabolites from an Eyelid using a Watercolor Pen based on Electrospray Ionization/Mass Spectrometry
Kai-Yin Chang (張凱茵), Cheng-Huang Lin (林震煌)*
時間 : 106 年 5 月 27 日 (六) 地點 : 國立中山大學理學院
DeveLoPment anD APPLIcatIon oF a BrusH-SPraY DerIveDFrom a CaLLIgraPHY-BrusH-StYLe SYntHetIc HaIr Pen For Use In ESI/MS Vol. 6 (2017), S0058
Page 1 of 4
Original Article
Development and Application of a Brush-Spray Derived from a Calligraphy-Brush-Style
Synthetic Hair Pen for Use in ESI/MS
Jen-Ying Liu, Pei-Chun Chen, Yea-Wenn Liou, Kai-Yin Chang, and Cheng-Huang Lin*
Department of Chemistry, National Taiwan Normal University, 88 Sec. 4, Tingchow Road, Taipei 11677, Taiwan
The development of a novel type of a sampling/ionization kit for use in electrospray ionization/mass spec-trometry is reported. Using a small calligraphy-brush-style synthetic hair pen (nylon-brush), and analogous to paper-spray mass spectrometry, the analytes can be collected, elution/desorption and then ionized from the surface of the nylon-brush. The body of the kit was produced by means of a commercial 3D-printer, in which ABS (acrylonitrile butadiene styrene) was used as the starting material. Meanwhile, a small nylon-brush was embedded inside a 3D-printed plastic cell, in which a solvent was supplied to rinse the nylon-brush by means of capillary action. The size and weight of the kit were 1 g and 4 cm, respectively. The kit is dispos-able and it has various functions, including non-invasive sampling, sample-evaporation and ionization. As a result, when a type of pesticide was selected as the test sample (dimethoate; C5H12NO3PS2), the limit of detection was determined to be 0.1 µg/mL. Collecting the pesticide from a leaf-surface (lettuce) was also successful. The process for fabricating the nylon-brush kit and the optimized experimental conditions are reported herein.
Copyright © 2017 Jen-Ying Liu, Pei-Chun Chen, Yea-Wenn Liou, Kai-Yin Chang, and Cheng-Huang Lin. This is an open access article distributed under the terms of Creative Commons Attribution License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Please cite this article as: Mass Spectrom (Tokyo) 2017; 6(2): S0058
Keywords: calligraphy-brush-style synthetic hair pen, nylon-brush, brush-spray/mass spectrometry, 3D-printer
(Received July 21, 2016; Accepted December 30, 2016)
INTRODUCTION
A wide variety of ionization methods have recently been developed. Among these methods, ambient ionization mass spectrometry is in widespread use, because it is quite simple and straightforward and also increases the speed of a mass-spectrum analysis.1–11) Furthermore, since the development of ambient ionization mass spectrometry, so-called paper spray-mass spectrometry (PS-MS) has opened new insights in the field of mass spectrometric analysis and, since its debut on 2010, it has now become a quite popular and important method for use in mass spectrometry.12) Thus far, PS-MS has been applied successfully in many areas of research, including food science,13) the analysis of protein complexes,14,15) biofluid samples,16,17) the online chemical monitoring of cell cultures,18) rapid discrimination of bac-teria,19) and drugs of abuse in whole blood or saliva,20–22) and even in an ambient organic analysis.23) Some novel al-ternate techniques based on PS-MS have also been reported, including a 3D-printed paper spray ionization cartridge/
continuous solvent supply and the rapid detection of cocaine
residues by paper spray ionization coupled with ion mobility spectrometry.24,25)
Analysis of pesticide residues provides a measure of the nature and level of chemical contamination within the envi-ronment and of its persistence. However, it is often difficult to correlate pesticide residues in the environment, since demonstrating whether vegetables or fruits have been ex-posed to chemicals can be a difficult task. Selected sampling programs can be used to investigate the levels of pesticide in the environment and to rapidly determine the uptake of a pesticide by food chain components.
In this study, dimethoate (O,O-dimethyl S-methylcar-bamoylmethyl phosphorodithioate; C5H12NO3PS2), a com-mon pesticide, was used as a test sample. We report on a combination of ambient ionization mass spectrometry and a simple sampling method that uses a calligraphy-brush-style synthetic hair pen. In general, there are two main types of brush tips: natural hair, i.e., animal hair, usually a weasel;
synthetic hair, which is generally made from nylon. Herein, a commercially available calligraphy-brush-style synthetic hair pen (nylon-brush) was used and modified to fit the kit (a homemade 3D-printed plastic cell), in which a high volt-DOI: 10.5702/massspectrometry.S0058
Page 1 of 4 (page number not for citation purpose)
* Correspondence to: Cheng-Huang Lin, Department of Chemistry, National Taiwan Normal University, 88 Sec. 4, Tingchow Road, Taipei 11677, Taiwan, e-mail: [email protected]
Mass SPectrometrY
DeveLoPment anD APPLIcatIon oF a BrusH-SPraY DerIveDFrom a CaLLIgraPHY-BrusH-StYLe SYntHetIc HaIr Pen For Use In ESI/MS Vol. 6 (2017), S0058
Page 2 of 4 age source can be applied. After obtaining a sample from
the target surface using the nylon-brush, it can be directly used in the ESI process, immediately followed by mass spec-trometric analysis. Details of the procedures for using the sampling/evaporation/ionization brush-kit and the limit of detection for dimethoate are also reported in detail.
MATERIALS AND METHODS
Acetonitrile, methanol and acetone were purchased from Merck (Darmstadt, Germany). Dimethoate was obtained from Riedel-de Haen (Seelze, Germany). Analytical-grade n-dodecane was purchased from Alfa Aesar (Heysham, England). Lettuce (test sample) and calligraphy-brush-style synthetic hair pens were purchased from a local supermar-ket and a local art supply store (model, #8), respectively.
A small bundle of synthetic pen hair (nylon) was cut to a length of 2 cm, and the resulting bundle of nylon hairs was imbedded in a piece of plastic tube (PE) to produce the nylon-brush, as shown in Fig. 1A. The seal cap (not shown), fixed cover, solvent cell (inside the body; capacity, 0.1 mL) and the body itself were fabricated by a 3D-printer, respectively. All of these parts are then combined to pro-duce a kit that can be used in sampling and ionization. The length, diameter and weight of the finished products are 3.5 cm, 1.0 cm and 1.1 g, respectively. Before use, the kit was cleaned by ultrasonication (Branson 3510), using deionized water and then methanol, each for 15 min. The 3D-printer was purchased from GoHOT (Model, UP! Plus). The mass spectrometer (Finnigan LCQ Classic LC/MS/MS) used in this study was the same instrument that was used in our previous study.11,20–22) The mass signal was recorded under the full scan mode (m/z 100–400). An Xcalibur data system was used for data collection, and the data were converted
into an ASCII text file. The capillary temperature and spray voltage were set at 200°C and 4.5 kV, respectively. The tube lens offset and capillary voltage were set at −36 and 36 V, respectively.
RESULTS AND DISCUSSION
Figure 1A shows a schematic drawing of the brush-kit. As reported above, the seal cap, fixed cover, solvent cell and the body were all prepared by means of a 3D-printer. The result-ing kit is economical, disposable and makes samplresult-ing easy.
When the seal cap was installed, it can be used sampling for the purpose for measuring the nature and level of any type of chemical contaminant. The volume of the solvent cell for loading can hold 0.4 mL of methanol. In fact, it was pos-sible to continuously rinse the nylon-brush, when methanol (at a rate of 6 µL/min), as an auxiliary liquid, was passed through the ESI needle. In order to investigate the sampling and ionization effect, various types of hair samples, i.e., nylon, from horse and weasel, respectively, were examined, and the findings indicated that a nylon-brush provided the most satisfactory results. This is because nylon-brush hairs are very smooth, tough and hydrophobic, which permits to ionization to occur within a very short period of time. It was found that when a 3 µL sample solution was loaded onto the brush by normal pipetting, a major peak appears during
∼0.1 sec, while a high voltage was applied. In contrast to this, when a chromatography paper was used, the ion intensity was weaker and decreased very slowly (up to ∼5 min). When vitamin B2 was selected as the test sample, the liner range of vitamin B2 was found from 0.1 to 100 ppm. Meanwhile the correlation coefficient was 0.98. The optimum ESI voltage for the procedure was also investigated. The ideal distance between the tip of the nylon-brush and the mass inlet was
Fig. 1. Upper drawing, schematic drawing of the brush-kit; bottom photo, actual situation for the mass inlet and the sampling/ionization kit used in this study.
DeveLoPment anD APPLIcatIon oF a BrusH-SPraY DerIveDFrom a CaLLIgraPHY-BrusH-StYLe SYntHetIc HaIr Pen For Use In ESI/MS Vol. 6 (2017), S0058
Page 3 of 4 determined to be 8 mm. Of course, this arrangement
depen-dents on different conditions, and the actual value would likely change, depending on the analytical parameters in use. Figure 1B (photo) shows the actual situation for the mass inlet when the sampling/ionization kit described above was used in this study. The kit is very light, so it can be held by an ordinary stainless ESI needle, in which a high volt-age is applied. The ESI needle was attached to a metric XYZ translation stage, and for this reason, axial alignment was readily achieved. Figure 2 shows 4 photos of the nylon-brush when various high voltages were applied (frames a–d; 3.5, 4.0, 4.5, and 5.0 kV, respectively). It can be seen that the Tay-lor cone is not clear when 3.5 kV was used. It should also be noted that the 3.5 kV was applied to the ESI needle, but not to the tip of the nylon-brush. The actual voltage would be expected to be lower, but the actual value was not measured.
On the other hand, when the voltage was increased to 5.0 kV, multiple Taylor cones were observed. Hence, the optimized voltage was found to 4.5 kV in this case. In Fig. 3, frame A shows a typical mass spectrum of the test sample (dimetho-ate) obtained using nylon-brush-spray/mass spectrometry.
Herein, a 15 mL aliquot of an aqueous stock solution, which was placed in a 20 mL sample vial, contained 1.0 ppm of dimethoate. By using a micropipette, the sample solution (3 µL of the dimethoate solution) was dropped on the nylon-brush, which was then subjected to direct detection by the mass spectrometer, in which a +4.5 kV high voltage power supply was used; an auxiliary solvent was not needed in this case. An ion intensity of 4.31×105 counts was observed, in the case of the above analysis. Using the kit, it was possible to detect amounts of dimethoate as low as 3 ng (absolute weight). Meanwhile, the peaks at m/z 199 and 252 are as-signed to the main fragment and [M+Na]+, respectively. The inset, in Fig. 3A bottom, shows the MS/MS spectrum of the parent ion, indicating that the peak at m/z 199 indeed was
the main fragment is belong to the parent ion. The other in-set, in Fig. 3A, shows a lower concentration level of dimetho-ate. As can be seen, a minor peak is also observed, i.e., the design of the brush-spray in ESI/MS, by using a calligraphy-brush-style nylon-hair pen, was successful, even though the concentration of the analyte was extremely low. To examine the sampling effect from a “leaf surface” by the nylon-brush, a procedure that could be used to analyze pesticide residues
Fig. 2. Photos show the nylon-brush when various high voltages were applied (frames a–d; 3.5, 4.0, 4.5, and 5.0 kV, respectively).
Fig. 3. Frame A, mass spectra of the test sample (dimethoate; concentration level, 1.0 ppm; inset, 0.1 ppm) obtained by nylon-brush-spray/mass spectrometry, respectively; frame B, a nylon-brush sampling/ESI method was performed. Lettuce was selected as the test sample and the spiked concentration and volume were 1.0 ppm and 50 µL, respectively.
DeveLoPment anD APPLIcatIon oF a BrusH-SPraY DerIveDFrom a CaLLIgraPHY-BrusH-StYLe SYntHetIc HaIr Pen For Use In ESI/MS Vol. 6 (2017), S0058
Page 4 of 4 on the surfaces of vegetables, lettuce was selected as the test
sample. Frame B, in Fig. 3, shows the results obtained when the surface of the lettuce was swept by the nylon-brush; us-ing methanol as the collection solvent. The spiked concen-tration and volume were 1.0 ppm and 50 µL, respectively. As can be seen, a very minor peak (indicated as [M+H]+) is ob-served and by comparing it to a blank sample, it is possible to identify it as arising from dimethoate. Furthermore, some additional peaks were also detected in this case, indicated as
“*”. This indicates that some unknowns, probably some nat-ural components associated with lettuce, were also extracted by the methanol when the nylon-brush was used. However, thus far we have not been able to identify these peaks. Thus, we conclude that the combination of brush-spray/ESI using a nylon-brush kit that was developed in this study, and am-bient ionization mass spectrometry provides a new approach for efficiently collecting low levels of pesticide residues that are present on the surfaces of vegetables.
CONCLUSION
The development of a novel method for nylon-brush-spray mass spectrometry by a calligraphy-brush-style nylon hair pen (nylon-brush) is described. By using a commercial 3D-printer, an economical and disposable nylon-brush kit was successfully designed and developed. The nylon-brush kit can be used for non-invasive sampling and the collected an-alytes can be simultaneously evaporated/ionized when the kit is connected to an ESI needle. This method is simple and economical, and is suitable for use in the rapid screening of pesticides, since it has a high degree of sensitivity. In addi-tion, the operating procedure is simple and an ion signal can be observed immediately. We believe this method has the potential for use in practical analyses and can also be re-garded as a helpful tool for use in examining environmental samples. Further applications are currently being explored.
Acknowledgements
This work was supported by a Grant from the National Science Council of Taiwan under Contract No.
103-2113-M-003-001-MY3.
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