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Rapid and reversible adsorption of BTX on mesoporous silica thin films for their real time spectrophotometric detection in air at ppm levels. Talanta 2019; 203:269-273. [DOI: 10.1016/j.talanta.2019.05.065] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 11/21/2022]
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2
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Ou-Yang CF, Liao WC, Wang PC, Fan GJ, Hsiao CC, Chuang MT, Chang CC, Lin NH, Wang JL. Construction of a cryogen-free thermal desorption gas chromatographic system with off-the-shelf components for monitoring ambient volatile organic compounds. J Sep Sci 2016; 39:1489-99. [DOI: 10.1002/jssc.201501336] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/25/2016] [Accepted: 02/15/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Chang-Feng Ou-Yang
- Department of Chemistry; National Central University; Taoyuan Taiwan
- Department of Atmospheric Sciences; National Central University; Taoyuan Taiwan
| | - Wei-Cheng Liao
- Department of Chemistry; National Central University; Taoyuan Taiwan
| | - Pei-Chieh Wang
- Department of Chemistry; National Central University; Taoyuan Taiwan
| | - Gang-Jei Fan
- Department of Chemistry; National Central University; Taoyuan Taiwan
| | - Chien-Cheng Hsiao
- Department of Chemistry; National Central University; Taoyuan Taiwan
| | - Ming-Tung Chuang
- Graduate Institute of Energy Engineering; National Central University; Taoyuan Taiwan
| | - Chih-Chung Chang
- Research Center for Environmental Changes; Academia Sinica; Taipei Taiwan
| | - Neng-Huei Lin
- Department of Atmospheric Sciences; National Central University; Taoyuan Taiwan
| | - Jia-Lin Wang
- Department of Chemistry; National Central University; Taoyuan Taiwan
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Kanou S, Nagaoka T, Kobayashi N, Kurahashi M, Takeda S, Aoki T, Tsuji T, Urano T, Abe T, Magatani K. Development of a new measurement system to detect selectively volatile organic compounds derived from the human body. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:3837-40. [PMID: 24110568 DOI: 10.1109/embc.2013.6610381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A new concept expired gas measurement system used double cold-trap method was developed. The system could detect selectively volatile organic compound (VOC) derived from the human body. The gas chromatography (GC) profiles of healthy volunteer's expired gas collected by our system were analyzed. As a result, 60 VOCs were detected from the healthy volunteer's expired gas. We examined 14 VOCs among them further, which could be converted to the concentration from the GC profiles. The concentration of almost VOCs decreased when the subjects inspired purified air compared with the atmosphere. On the other hand, isoprene was almost the same. It was strongly suggested that these VOCs were derived from the human body because the concentration of these VOCs in the atmosphere were nearly zero. Expired gas of two sleep apnea syndrome (SAS) patients were analyzed as preliminary study. As a result of the study, the concentration of some VOCs contained in the expired gas of the SAS patients showed higher value than a healthy controls.
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5
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Investigation and optimization of particle dimensions for needle trap device as an exhaustive active sampler. J Chromatogr A 2012; 1260:54-60. [DOI: 10.1016/j.chroma.2012.08.089] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Revised: 08/24/2012] [Accepted: 08/27/2012] [Indexed: 11/22/2022]
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6
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Full-range analysis of ambient volatile organic compounds by a new trapping method and gas chromatography/mass spectrometry. J Chromatogr A 2011; 1218:5733-42. [DOI: 10.1016/j.chroma.2011.06.067] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 06/13/2011] [Accepted: 06/16/2011] [Indexed: 11/21/2022]
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7
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Su YC, Kao HM, Wang JL. Mesoporous silicate MCM-48 as an enrichment medium for ambient volatile organic compound analysis. J Chromatogr A 2010; 1217:5643-51. [DOI: 10.1016/j.chroma.2010.06.065] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 06/14/2010] [Accepted: 06/24/2010] [Indexed: 10/19/2022]
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8
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Schüpfer PY, Huynh CK. Solid phase microextraction as a short-term sampling technique for BTEX occupational exposure. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2008; 5:490-500. [PMID: 18569516 DOI: 10.1080/15459620802177484] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Solid phase microextraction (SPME) has been widely used for many years in various applications, such as environmental and water samples, food and fragrance analysis, or biological fluids. The aim of this study was to suggest the SPME method as an alternative to conventional techniques used in the evaluation of worker exposure to benzene, toluene, ethylbenzene, and xylene (BTEX). Polymethylsiloxane-carboxen (PDMS/CAR) showed as the most effective stationary phase material for sorbing BTEX among other materials (polyacrylate, PDMS, PDMS/divinylbenzene, Carbowax/divinylbenzene). Various experimental conditions were studied to apply SPME to BTEX quantitation in field situations. The uptake rate of the selected fiber (75 microm PDMS/CAR) was determined for each analyte at various concentrations, relative humidities, and airflow velocities from static (calm air) to dynamic (> 200 cm/s) conditions. The SPME method also was compared with the National Institute of Occupational Safety and Health method 1501. Unlike the latter, the SPME approach fulfills the new requirement for the threshold limit value-short term exposure limit (TLV-STEL) of 2.5 ppm for benzene (8 mg/m(3)).
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Affiliation(s)
- Patrick Y Schüpfer
- Institut universitaire romand de Sante au Travail (Institute for Work and Health)-University of Lausanne, Lausanne, Switzerland.
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9
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Modelling of adsorption kinetics and calibration curves of gaseous volatile organic compounds with adsorptive solid-phase microextraction fibre: toluene and acetone for indoor air applications. Anal Bioanal Chem 2008; 392:97-104. [DOI: 10.1007/s00216-008-2249-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 06/11/2008] [Accepted: 06/12/2008] [Indexed: 10/21/2022]
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10
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Nian HC, Liu HW, Wu BZ, Chang CC, Chiu KH, Lo JG. Impact of inclement weather on the characteristics of volatile organic compounds in ambient air at the Hsinchu Science Park in Taiwan. THE SCIENCE OF THE TOTAL ENVIRONMENT 2008; 399:41-49. [PMID: 18479737 DOI: 10.1016/j.scitotenv.2008.01.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 01/25/2008] [Accepted: 01/30/2008] [Indexed: 05/26/2023]
Abstract
This study describes continuous monitoring of the volatile organic air pollutants, acetone and toluene, in Hsinchu Science Park (HSP) during an occurrence of inclement weather, i.e., a typhoon. Using a lab-designed sampling system coupled with a continuous automated GC-MS analysis system, a total of 53 polar and nonpolar compounds were identified and quantified. The concentration of polar compounds dropped sharply from 41.4 ppbv before the typhoon to the stage of no detection during the storm, but rose again after the typhoon. The amount of nonpolar compounds remained unaffected during the storm. The polar compounds were more affected by both the rainfall and wind than were the nonpolar compounds. The severity of air pollution strongly correlates with the concentration of acetone released into the atmosphere by a wastewater treatment facility. The system used in this study has been proved reliable while working in inclement weather condition; in addition, the results can probably be applied in the monitoring of the environment during the typhoon season in high-tech research areas.
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Affiliation(s)
- Hung-Chi Nian
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 300, Taiwan, ROC
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11
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Pal R, Kim KH. The effect of cold trap adsorbents on the gas chromatographic analysis of ambient VOCs under Peltier cooling conditions. J Sep Sci 2008; 31:1100-9. [DOI: 10.1002/jssc.200700531] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Mocho P, Larroque V, Desauziers V. Modelling of toluene solid-phase microextraction for indoor air sampling. Anal Bioanal Chem 2007; 388:147-56. [PMID: 17372722 DOI: 10.1007/s00216-007-1231-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 02/21/2007] [Accepted: 02/22/2007] [Indexed: 10/23/2022]
Abstract
Solid-phase microextraction (SPME) is a convenient and efficient sampling technique recently applied to indoor air analysis. We propose here a theoretical model of the adsorption kinetics of toluene on SPME fibre under static extraction conditions. We discuss the effects of sampling volume and initial concentration of analyte on the adsorption kinetics. This model is used to estimate the limits of detection taking into account operating conditions and to calculate theoretical calibration curves. Results of comparison with experimental data are encouraging: only 11% difference for calibration curves and 30% for the estimation of the limit of detection. On the basis of this kinetics model, the solid concentration gradient in the Carboxen coating was modelled with Fick's second law of diffusion in unsteady-state mass-transfer mode. Mass diffusion from the gas sample to the SPME fibre was also investigated. It was shown that diffusion is the limiting step of the mass-transfer process in the static mode. Thus, the model developed, allows a better understanding of adsorption on Carboxen fibre and in the future could be a useful tool for cheap and time-saving development of SPME methods and the estimation of sampling performance.
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Affiliation(s)
- Pierre Mocho
- Laboratoire Thermique Energétique et Procédés, Université de Pau et des Pays de l'Adour, B.P. 1155, 64000, Pau, France
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Wu TM, Wu GR, Kao HM, Wang JL. Using mesoporous silica MCM-41 for in-line enrichment of atmospheric volatile organic compounds. J Chromatogr A 2006; 1105:168-75. [PMID: 16209870 DOI: 10.1016/j.chroma.2005.09.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 09/12/2005] [Accepted: 09/13/2005] [Indexed: 11/15/2022]
Abstract
A mesoporous silica MCM-41 with pore size of 29A was synthesized and assessed for its applicability as a sorbent for in-line trapping of volatile organic compounds (VOCs) from air samples. Several commercially available microporous carbon molecular sieves, i.e., Carbosieve SIII, Carboxen 1000, Carboxen 1003, and Carbotrap purchased from Supelco, were employed to form either single sorbent traps or multi-sorbent traps for comparing adsorption properties with those of the silica MCM-41. A standard gas mixture containing more than 50 target compounds with size varying from C(2) to C(12) was adsorbed by these sorbents and the per carbon response of flame ionization detection (FID) for the target compounds was calculated for obtaining the adsorption profiles. While the multi-carbon sorbents show very uniform adsorption ability across the entire carbon range from C(3) to C(12), the mesoporous silica MCM-41, however, shows little sorption for smaller molecules from C(3) to C(7), but exhibit comparable sorption ability for C(8)-C(12) compounds. Desorption at various temperatures indicates that C(8)-C(12) compounds once trapped can be easily released at moderate temperatures of about 150 degrees C, whereas for carbon sorbents the desorption temperatures for sufficient recovery need to go beyond 300 degrees C due to much tighter hold-up in the microporous structure. Sorption ability for MCM-41 is also reflected on linearity. Compounds with sufficient sorption as suggested by the adequate per carbon response also exhibit excellent precision and linearity with R(2) close to unity, an important requirement for quantitative analysis of ambient VOCs.
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Affiliation(s)
- Tung-Min Wu
- Department of Chemistry, National Central University, Chungli 320, Taiwan
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14
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Wang CH, Chang CC, Wang JL. Peak tailoring concept in gas chromatographic analysis of volatile organic pollutants in the atmosphere. J Chromatogr A 2005; 1087:150-7. [PMID: 16130708 DOI: 10.1016/j.chroma.2005.03.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
An automated gas chromatographic system aiming at performing unattended analysis of volatile organic compounds (VOCs) was developed in laboratory. To encompass VOCs of a wide range of volatility, two different designs of enrichment and separation methods were adopted and compared with performance in analyzing ozone precursors of C3-C12. In the dual-trap dual-column design, lower boiling species (C3-C6) are enriched and separated by one set of trap and column (porous layer open tubular (PLOT)), whereas the enrichment and separation for the higher boiling species (C6-C12) are performed by the other set (wall-coated open tubular (WCOT)). Undesired peaks also inevitably appear on both chromatograms often causing annoyances. To reduce complexity of both the apparatus and the resulting chromatograms, the heart-cut technique was adopted as a base for developing a system, which only uses one trap and one flame ionization detector for constructing two-dimensional GC with PLOT and DB-1. Methods were developed to allow the auxiliary flow pressure in the heart-cut device to be programmed to create dual effects, which not only can perform regular heart-cut actions but can also temporally hold up species in the precolumn for prescribed time intervals. Because it is characteristic for PLOT chromatograms to have reproducible blank retention time windows, segments of a DB-1 trace are produced by the auxiliary flow program aligning perfectly in time with the gaps of the PLOT trace. Subsequently, the two column flows are merged and channeled into single flame ionization detector to produce a very condensed "tailored" chromatogram which is equivalent to overlaying a PLOT and a DB-1 chromatogram on top of each other, except that no peaks are overlapped. This innovative "peak tailoring" concept based on the heart-cut technique is simple in design, easy to build, and extremely rugged for long-term continuous operation as fewer moving parts are involved, which is beneficial for deploying in remote monitoring stations.
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Affiliation(s)
- Chieh-Heng Wang
- Department of Chemistry, National Central University, Chungli 320, Taiwan
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15
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Chen TY, Li MJ, Wang JL. Sub-second thermal desorption of a micro-sorbent trap for the analysis of ambient volatile organic compounds. J Chromatogr A 2002; 976:39-45. [PMID: 12462594 DOI: 10.1016/s0021-9673(02)01073-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study investigates a novel approach of fast thermal desorption on a micro-sorbent trap for analyzing ambient volatile organic compounds (VOCs) by gas chromatography with flame ionization detection. Unlike conventional approaches, the temperature feedback mechanism for temperature control was abandoned, which often poses a limit to the heating speed due to slow response of the sensor and the control algorithm. Instead, a series of programmed a.c. pulses was given to the Ni-Cr wire coiled around the micro-trap to perform instant heating from room temperature to 250 degrees C within a fraction of a second, maintained at 250 degrees C during injection, and subsequently to 300 degrees C for trap cleaning. Temperature fluctuation around a high temperature set point could be maintained within +/- 10 degrees C. Significant improvement in resolution and peak height was obtained compared to a trap with temperature feedback and control algorithm. While keeping resolution at a satisfactory level, the sub-second desorption approach allows faster chromatography and at the same time increases the sensitivity of VOC analysis.
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Affiliation(s)
- Tai-Yi Chen
- Institute of Earth Sciences, Academia Sinica, Taipei 11529, Taiwan
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16
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Tuduri L, Desauziers V, Fanlo JL. Dynamic versus static sampling for the quantitative analysis of volatile organic compounds in air with polydimethylsiloxane-carboxen solid-phase microextraction fibers. J Chromatogr A 2002; 963:49-56. [PMID: 12188000 DOI: 10.1016/s0021-9673(02)00222-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Polydimethylsiloxane-Carboxen solid-phase microextraction fibers are now well known to be very efficient trapping media for the analysis of volatile organic compound (VOC) traces in air. However, competitive adsorption, due to the nature of the coating, considerably limits analyte quantitation. In this contribution, different experimental conditions are investigated to achieve quantitative analysis. Static and dynamic sampling were compared for the analysis of 11 VOCs in a standard gaseous mixture at different extraction times (1, 5, 15 and 45 min). The same experiments were performed with four isolated compounds. Adsorption results from gas mixture and isolated compounds were compared and a common linear range (i.e., where quantitative analysis is conceivable) was determined. When sampling was in the dynamic mode, compounds with lower affinity for the coating showed a very narrow linear range, meaning that competition for adsorption was quickly discriminative. The same experiments in static mode allowed one to obtain wider linear ranges for all compounds, especially for lower-affinity compounds: for a 1 min sampling time, acetone showed a linear adsorption range from 3 to 60 microg m(-3) in the dynamic mode which extended from 5 to 300 microg m(-3) in the static mode.
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Affiliation(s)
- Ludovic Tuduri
- Laboratoire Génie de l'Environnement Industriel, Ecole des Mines d'Alès, France.
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17
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Determination of Volatile Organic Compounds (VOCs) Using Tedlar Bag/Solid-phase Microextraction/Gas Chromatography/Mass Spectrometry (SPME/GC/MS) in Ambient and Workplace Air. B KOREAN CHEM SOC 2002. [DOI: 10.5012/bkcs.2002.23.3.488] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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18
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Wang JL, Chen WL, Tsai SY, Sung PY, Huang RN. An in vitro model for evaluation of vaporous toxicity of trichloroethylene and tetrachloroethylene to CHO-K1 cells. Chem Biol Interact 2001; 137:139-54. [PMID: 11551530 DOI: 10.1016/s0009-2797(01)00226-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Toxicokinetics of trichloroethylene (TCE) and tetrachloroethylene (PER) in culture medium and their toxicity to CHO-K1 cells were investigated by employing an in vitro vapor exposure system. Cells were cultured in a 60 mm petri dish with a 25 mm glass dish glued in the central area. TCE or PER was added to the central glass dish so that it would evaporate and dissolve in the surrounding medium in which cells were growing. The results showed that the concentration of TCE or PER in medium increased significantly within 20 min and then decreased very rapidly with time. After a 24 h incubation, the residual of TCE or PER in the medium was very low, but was displayed in a dose-dependent manner. Treatment of cells with either TCE or PER resulted in a dose- and time-dependent inhibition of cell growth. A significantly increase in the frequency of micronuclei (MN) was also observed with either TCE or PER treatment. Low doses of TCE (5-20 microl) or PER (1-5 microl) significantly enhanced the intracellular glutathione (GSH) level. However, the level of GSH rapidly decreased with higher doses of TCE (40-80 microl) or PER (10-20 microl). Depletion of cellular GSH showed no effect on the sensitivity of cells to TCE or PER treatment. GSH-conjugation has been proposed as an activation mechanism to account for the nephrotoxicity of TCE and PER, however the toxicity of TCE and PER to CHO-K1 cells is probably mediated through a distinct mechanism.
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Affiliation(s)
- J L Wang
- Department of Chemistry, National Central University, Chung-li, 32054, Taoyuan, Taiwan, ROC
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19
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Wang JL, Chen WL. Construction and validation of automated purge-and-trap-gas chromatography for the determination of volatile organic compounds. J Chromatogr A 2001; 927:143-54. [PMID: 11572383 DOI: 10.1016/s0021-9673(01)01074-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
An automated purge-and-trap chromatographic system for the determination of dissolved volatile organic compounds in aqueous samples was built in the laboratory with minimum cost both in the construction and routine operation. This system was built upon a commercial gas chromatograph with full automation capability using self-developed hardware and software. The use of a multi-sorbent bed quantitatively trapped a wide range of volatile organic compounds at ambient temperature, including the extremely volatile ones such as dichlorofluoromethane (CFC-12). Flash heating for rapid desorption and adequate plumbing for minimizing dead volume resulted in excellent chromatographic separation at above-ambient temperatures, which eliminated the need for cryogen for cooling at the head of the column, a second refocusing stage, or entire GC oven for refocusing. This cryogen-free system was tested with standard solutions and environmental samples for determining hydrocarbons with flame ionization detection, and halogenated compounds with electron-capture detection. An innovative method was also developed for validating the system's linearity for extremely volatile compounds. By introducing ambient air, which usually contains constant levels of anthropogenic halocarbons, e.g., CFC-12 and CFC-11 (CCl3F), the need to prepare aqueous standards containing extremely volatile compounds is avoided, hence providing a convenient method for evaluating a purge-and-trap system.
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Affiliation(s)
- J L Wang
- Department of Chemistry, National Central University, Chung-Li, Taiwan.
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20
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Wang JL, Chen WL, Lin YH, Tsai CH. Cryogen free automated gas chromatography for the measurement of ambient volatile organic compounds. J Chromatogr A 2000; 896:31-9. [PMID: 11093637 DOI: 10.1016/s0021-9673(00)00583-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An automated gas chromatographic system was constructed for measuring ambient volatile organic compounds (VOCs). Preconcentration of the VOCs was performed by using two separated sorbent traps of different combinations with each designated for either low or high boiling VOCs. Both traps and their associated valve systems were integrated as a complete system sharing a common sample inlet. Precise temperature controls for desorption relied on the use of a process controller with proportional-integral-derivative algorithm to throttle the current supply. No additional cryo-focusing stage prior to the column was needed owing to the flash heating capability for desorption. Other than the cryogen free preconcentration and focusing, the separation of VOCs of large volatility difference was also performed without cryogen. The system employed an Al2O3/KCl porous-layer open tubular column for separating C3-C7 compounds; and a DB-1 column for C6-C12. This automated GC system has been deployed in a Taiwan Environmental Protection Agency urban air quality monitoring station of Taiwan for continuous measuring C3-C7 ozone precursors. Excellent correlation between the car exhaust type of compounds measured by our GC system and carbon monoxide measured by a non-dispersive infrared spectrometer was observed, suggesting the automated GC system was robust and reliable.
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Affiliation(s)
- J L Wang
- Department of Chemistry, National Central University, Chungli, Taiwan.
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Abstract
The use of sorbents in trapping volatile organic compounds in air for subsequent analysis is reviewed. Sorbents are classified in accordance with the mechanism used to recover the trapped compounds, either solvent or thermal desorption. The use of sorbents is contrasted with other sampling procedures, such as collecting whole air samples using canisters. New developments such as solid-phase microextraction are described. In particular, emphasis is placed on a holistic approach to sampling and analysis, and communication is encouraged between those who take samples in the field, and those who perform the analysis.
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Affiliation(s)
- M Harper
- University of Alabama at Birmingham, School of Public Health, Department of Environmental Health Sciences 35294-0022, USA.
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