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Kawasaki, Japan

Suzuki Y.,Yamanashi University | Sato N.,Yamanashi University | Nakamaru T.,GASTEC Corporation | Miyajima N.,Yamanashi University | Kawakubo S.,Yamanashi University
Bunseki Kagaku | Year: 2015

An accurate discrimination system of the color-change point for detector tubes has been developed. A gaseous or liquid sample is passed through a tube that packs granules coated with a colorimetric reagent, and the color-change point is discriminated by the developed system. The tube is photographed by a digital still camera, and the image is analyzed by color-analysis software installed on a PC. This software digitizes the color information of each point under the line specified by the user, and displays a graph. In order to reduce noise on the graph, the moving average, as well as fast-Fourier transformation and inverse fast-Fourier transformation smoothing functions are implemented. A differentiation function used to identify the color-change point and color-control function to emphasize the color change are also implemented. This system has been applied to detector tubes including ammonia, hydrogen chloride, chloride anion, toluene, water vapor, and 2-propanol, and their colorchange points have been successfully discriminated. © 2015 The Japan Society for Analytical Chemistry. Source


Takeuchi A.,Osaka Occupational Health Service Center | Nishimura Y.,GL Sciences Inc. | Kaifuku Y.,GASTEC Corporation | Imanaka T.,GL Sciences Inc. | And 6 more authors.
Journal of Occupational Health | Year: 2010

Objectives: The purpose of this research was to develop a determination method for nitromethane (NM) in workplace air for risk assessment. Methods: A suitable sampler and appropriate desorption condition were selected by a recovery test in which a spiked sampler was used. The characteristics of the proposed method, such as recovery, detection limit, and reproducibility, and the storage stability of the sample were examined. Results: A sampling tube containing bead-shaped activated carbon was chosen as the sampler. NM in the sampler was desorbed with acetone and analyzed by a gas chromatograph equipped with a flame ionization detector. The recoveries of NM from the spiked sampler were 81-97% and 80-98% for personal exposure monitoring and working environment measurement, respectively. On the first day of storage in a refrigerator, the recovery from the spiked samplers exceeded 90%; however, it decreased dramatically with increasing storage time. In particular, the decrease was more remarkable for the smaller spiked amounts. The overall LOQ was 2 μg/sample. The relative standard deviation, which represents the overall reproducibility, was 1.1-4.0%. Conclusions: The proposed method enables 4-hour personal exposure monitoring of NM at concentrations equaling 0.001-2 times the threshold limit value-time-weighted average (TLV-TWA: 20 ppm) proposed by the American Conference of Governmental Industrial Hygienists, as well as 10-minute working environment measurement at concentrations equaling 0.02-2 times TLV-TWA. Thus, the proposed method will be useful for estimating worker exposure to NM. Source


Takeuchi A.,Osaka Occupational Health Service Center | Jukurogi A.,GL Sciences Inc. | Kaifuku Y.,GASTEC Corporation | Natsumeda S.,Baxter Ltd | And 4 more authors.
Journal of Occupational Health | Year: 2013

Determination Method for p-Phenylazoaniline and 2-methyl-4-(2-tolylazo)aniline in Workplace Air by High-performance Liquid Chromatography: Akito TAKEUCHI, et al. Osaka Occupational Health Service Center, Japan Industrial Safety and Health Association-Objectives: The purpose of this research was to develop a method for the simultaneous determination of p-phenylazoaniline (also called 4-aminoazobenzene, AAB) and 2-methyl-4-(2-tolylazo)aniline (also called o-aminoazotoluene, AAT) in workplace air for risk assessment. Methods: The characteristics of the proposed method, such as recovery, limit of quantitation, reproducibility and storage stability of the samples were examined. Results: An air sampling cassette containing two sulfuric acid-treated glass fiber filters was chosen as the sampler. The AAB and AAT were extracted from the sampler filters by methanol and then analyzed by a high-performance liquid chromatograph equipped with a photo-diode array detector. The overall recoveries from spiked samplers were 77-98 and 85-98% for AAB and AAT, respectively. The recovery after 5 days of storage in a refrigerator exceeded 96%. The overall limits of quantitation were 5.00 and 2.50 μg/sample for AAB and AAT, respectively. The relative standard deviations, which represent the overall reproducibility defined as precision, were 0.6-1.8 and 0.5-2.2% for AAB and AAT, respectively. Conclusions: The proposed method enables 4-h personal exposure monitoring of AAB and AAT at concentrations of 21 to 2,000 μg/m3 for AAB and 10 to 2,000 μg/m3 for AAT, respectively. The proposed method Determination Method for p-Phenylazoaniline and 2-methyl-4-(2-tolylazo)aniline in Workplace Air by High-performance Liquid Chromatography: Akito TAKEUCHI, et al. Osaka Occupational Health Service Center, Japan Industrial Safety and Health Association-Objectives: The purpose of this research was to develop a method for the simultaneous determination of p-phenylazoaniline (also called 4-aminoazobenzene, AAB) and 2-methyl-4-(2-tolylazo)aniline (also called o-aminoazotoluene, AAT) in workplace air for risk assessment. Methods: The characteristics of the proposed method, such as recovery, limit of quantitation, reproducibility and storage stability of the samples were examined. Results: An air sampling cassette containing two sulfuric acid-treated glass fiber filters was chosen as the sampler. The AAB and AAT were extracted from the sampler filters by methanol and then analyzed by a high-performance liquid chromatograph equipped with a photo-diode array detector. The overall recoveries from spiked samplers were 77-98 and 85-98% for AAB and AAT, respectively. The recovery after 5 days of storage in a refrigerator exceeded 96%. The overall limits of quantitation were 5.00 and 2.50 μg/sample for AAB and AAT, respectively. The relative standard deviations, which represent the overall reproducibility defined as precision, were 0.6-1.8 and 0.5-2.2% for AAB and AAT, respectively. Conclusions: The proposed method enables 4-h personal exposure monitoring of AAB and AAT at concentrations of 21 to 2,000 μg/m3 for AAB and 10 to 2,000 μg/m3 for AAT, respectively. The proposed method is useful for estimating worker exposure to AAB and AAT. Source


Hatano T.,Japan Atomic Energy Agency | Hiratsuka H.,Japan Atomic Energy Agency | Hasegawa K.,Japan Atomic Energy Agency | Kaifuku Y.,GASTEC Corporation | Abe T.,Japan Atomic Energy Agency
Journal of the Vacuum Society of Japan | Year: 2011

Development of the precision gas generator tagged by a very small amount of the released gas rate in weight change (g/sec) has been strongly desired for exactly calibrating vacuum instruments. The gas-liquid equilibrium type, permeation tube (P-tube) for the Japanese Industrial Standards (JIS) to prepare the released rate of a calibration gas in an atmospheric pressure has not been used in vacuum elsewhere. Therefore in this study, the performance of the P-tube in vacuum environment was evaluated. A weight change of the P-tube was measured with our original vacuum microbalance, and concentrations of the released gas components were concurrently measured with the Electron Ionization Quadrupole Mass Spectrometer (EI-QMS), both in the different P-tube temperatures. The resultant correlation between the vacuum microbalance and the EI-QMS was discussed. The weight change rate of the sample propane (C 3H 8) and butane (C 4H 10) gases encapsulated in the P-tube were nearly identical from 35°C to 45°Cand from 40°C to 50°C, respectively. The EI-QMS peak intensities of m/z = 29 (propane) and m/z = 43 (butane) indicated constant values, both in the above temperature ranges. These results can be positioned to the initial performance data for realizing the weight change rate tagged precision gas generator in vacuum by using the P-tube. Source


Takeuchi A.,Osaka Occupational Health Service Center | Kitade T.,MandS Instruments Inc. | Jukurogi A.,GL Sciences Inc. | Hendricks W.,Health-U | And 8 more authors.
Journal of Occupational Health | Year: 2012

Objectives: The purpose of this research was to develop a simultaneous determination method for monoethanolamine (MEA) and diethanolamine (DEA) in workplace air for risk assessment. Methods: The characteristics of the proposed method, such as recovery, quantitation limit, reproducibility and storage stability of the samples, were examined. Results: An air sampling cassette containing two sulfuric acid-treated glass fiber filters was chosen as the sampler. The MEA and DEA were extracted from the sampler filters, derivatized with 9-fluorenylmethyloxycarbonyl chloride and then analyzed by a high-performance liquid chromatograph equipped with a fluorescence detector or photo-diode array detector. The overall recoveries from spiked samplers were 86-99 and 88-99% for MEA and DEA, respectively. The recovery after 5 days of storage in a refrigerator exceeded 95%. The overall limits of quantitation were 0.750 and 0.100 μg/sample for MEA and DEA, respectively. The relative standard deviations, which represent the overall reproducibility defined as precision, were 0.3-1.6 and 0.4-5.7% for MEA and DEA, respectively. Conclusions: The proposed method enables 4-h personal exposure monitoring of MEA and DEA at concentrations equaling 1/3,000-2 times the threshold limit value-time-weighted average (TLV-TWA: 3 ppm for MEA, 1 mg/m3 for DEA) adopted by the American Conference of Governmental Industrial Hygienists and also by the Japan Society for Occupational Health. The method is useful for estimating worker exposure to MEA and DEA. Source

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