Browsing by Author "Chen, Ssu-Ying"

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Automated system for extraction and instantaneous analysis of millimeter-sized samples
(2014)
Hu, Jie-Bi
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Chen, Ssu-Ying
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Wu, June-Tai
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Chen, Yu-Chie
;
Urban, Pawel L.
Adequate sample treatment is critical when employing mass spectrometry (MS) in the analyses of complex biological matrices. Despite various improvements, it is generally difficult to automate the process of preparing solid biological samples for MS analysis. Here we demonstrate a facile approach for automation of the whole analysis (from an untreated sample to the final result). The proposed platform enables disruption and extraction of relatively small samples (individual fruit flies, fragments of tea leaves, powdered drug sampled with a cotton bud), and almost simultaneous analysis of the obtained extract within less than 10 min, and with very little intervention of the analyst. The operation is straightforward: once a sample is placed in the sample chamber, the analyst only needs to press a button on the touch screen of the user interface. The programmed open-source electronic device triggers addition of a small amount of solvent, and subsequent mechanical disruption/extraction of the specimen under controlled conditions (thermostated chamber). A small volume of the extract is directed to the ion source of the mass spectrometer incorporating a Venturi pump. During the operation of the instrument, fluorescence intensities (excitation wavelength windows: 320-380 and 460-500 nm) as well as MS extracted ion currents are recorded simultaneously. In the case of fruit fly samples, similar to 70 signals were recorded in both modes while the analysis of green tea leaves yielded similar to 30 signals. The resulting data reveal time-resolved extraction profiles characterizing every sample.
On-line monitoring of Soxhlet extraction by chromatography and mass spectrometry to reveal temporal extract profiles
(2015-06-30)
Chen, Ssu-Ying
;
Urban, Pawel L.
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應用化學系
;
應用化學系分子科學碩博班
;
Department of Applied Chemistry
Soxhlet extraction is a popular sample preparation technique used in chemical analysis. It enables liberation of molecules embedded in complex matrices (for example, plant tissues, foodstuffs). In most protocols, samples are analyzed after the extraction process is complete. However, in order to optimize extraction conditions and enable comparisons between different types of extraction, it would be desirable to monitor it in real time. The main development of this work is the design and construction of the interface between Soxhlet extractor and GC-MS as well as ESI-MS system. The temporal extract profiles, obtained in the course of real-time GC-MS monitoring, have been fitted with mathematical functions to analyze extraction kinetics of different analytes. For example, the mass transfer coefficients of pinene, limonene and terpinene in lemon sample, estimated using the first-order kinetic model, are 0.540 h(-1), 0.507 h(-1) and 0.722 h(-1), respectively. On the other hand, the Peleg model provides the following extraction rates of pinene, limonene and terpinene: 0.370 nM h(-1), 0.216 nM h(-1) and 0.596 nM h(-1), respectively. The results suggest that both first-order kinetic and Peleg equations can be used to describe the progress of Soxhlet extraction. On-line monitoring of Soxhlet extraction reveals extractability of various analytes present in natural samples (plant tissue), and can potentially facilitate optimization of the extraction process. (C) 2015 Elsevier B.V. All rights reserved.
One-Step Detection of Major Lipid Components in Submicroliter Volumes of Unpurified Liposome and Cell Suspensions
(2016-07-19)
Chen, Ssu-Ying
;
Wu, Ching-Yi
;
Chen, Yu-Chie
;
Urban, Pawel L.
;
應用化學系
Liposomes and cells have high lipid contents, which are the main components of the external and internal membranes. Mass spectrometry (MS) is widely used in the analysis of the lipids present in the biological matrixes. However, MS analysis of liposome and cell suspensions is challenging due to the presence of other high-abundance matrix components (e.g., salts, buffers, and growth media) that cause ion suppression. These interfering species would normally be removed by dialysis or centrifugation. Here we propose a simple and fast method to detect major lipid components in cells and cell suspensions by MS while circumventing dialysis and centrifugation. Capillary hydrodynamic chromatography (HDC) has been coupled online with the aid of an electrospray ionization (ESI) interface to an ion-trap mass spectrometer. Complex samples containing biopartides and a large amount of potential interferences (buffer, inorganic salts, amino acids) were separated hydrodynamically, detected optically (by light absorption/scattering), and immediately transferred to the MS interface. Liposomes and animal cells are disintegrated during electrospray, and the constituent lipids are ionized. The signal-to-noise ratios are similar to 10x higher in HDC-ESI-MS than in direct infusion ESI-MS experiments (with or without dilution). This method has been tested on liposomes (containing phosphatidylcholine and phosphatidylglycerol) and four types of animal/human cells, i.e., mouse macrophages (RAW 264.7), human breast cancer cells (T47D and HsS78T), and mouse preadipoc-yte cells (3T3-L1). We suggest that HDC-ESI-MS can be used in quality control analyses of bioparticle suspensions in the fields of biotechnology, molecular biology, drug discovery, and cosmetics.