A Method for On‐Site Analysis of Urinary Benzene by Means of a Portable Gas‐Chromatograph

Evaluation of three dimensional high nitrogen doped graphene as an efficient sorbent for the preconcentration of BTEX compounds in environmental samples

A simple and highly sensitive method that involves SPE-GC with three dimensional high nitrogen doped graphene as a novel sorbent used for determination of BTEX compounds in environmental samples.

Person-portable gas chromatography: rapid temperature program operation through resistive heating of columns with inherently low thermal mass properties

As open tubular gas chromatography was becoming widely adopted, the potential to rapidly heat and cool the low thermal mass of an open tubular fused silica column was recognized. Numerous resistive column heating approaches were subsequently described and demonstrated, often with a common objective to focus heating efforts on the column alone, rather than on a large convection oven. Low thermal mass column bundles have been commercially available for about ten years, where insulated wires in close proximity to a coiled open tubular capillary column provide resistive heating. Before this, person-portable gas chromatographs either operated isothermally at relatively low temperatures or at ambient temperature to lessen power demands, but several person-portable gas chromatography-mass spectrometry (GC-MS) instruments capable of temperature program operation have become available in the past ten years based on this heating method. When low thermal mass heated zones are used, and with a direct GC-MS interface, analysis times of less than 5 min are possible for target compounds having a wide range of volatilities. Previous capabilities in transportable and person-portable gas chromatography instrumentation are reviewed to demonstrate the scale of advancement made possible by the adoption of open tubular columns and low power heating techniques now becoming routinely available. Microcomachined columns which are usually etched in a silicon wafer represent a radical break from the traditional fused silica open tubular column design, and increasing efforts to use this column construction approach are also examined. The developments discussed have introduced the potential to rapidly analyze compounds with a wide volatility range in the field to protect deployed military forces, the health of workers, and the health of the general public.

Possible sources of urinary benzene among nonoccupationally exposed Japanese subjects

Unmetabolized benzene in urine (U-benzene) is known to be the best marker among the indices for the biological monitoring of occupational and environmental exposure to benzene. In this study, we determined the levels of U-benzene among Japanese university students exposed to benzene nonoccupationally and analyzed the relation between U-benzene levels and the possible factors responsible for environmental benzene exposure. In urinalysis, U-benzene concentration among 124 students was detected in the range from 18 (minimum detection limit) to 249 ng/l. The frequency distribution of U-benzene concentration peaked at 0-19 ng/l. Mean and median values of 40 and 20 ng/l for U-benzene concentration in nonoccupationally exposed subjects were lower than those in a previous study. Stepwise multiple linear regression analysis was performed to assess the potential sources of exposure to environmental benzene by analyzing the relation between U-benzene and personal, behavioral, and environmental factors. The results showed that only smoking habit (P < 0.01) and residential house age (P < 0.05) were independent determinants of U-benzene levels. In addition, U-benzene levels in relation to smoking and house age suggested that these factors could be associated with the synergistic elevation of U-benzene. The present study showed U-benzene levels among non-occupationally exposed Japanese subjects and revealed that the major exposure sources to benzene in the general environment were tobacco smoking and indoor air contamination.