[Determination of thiodiglycolic acid in urine with gas chromatography-mass spectrometer].

OBJECTIVE: To establish a rapid determination method with gas chromatography-mass spectrometer (GC-MS) for thiodiglycolic acid (TDGA), a vinyl chloride (VCM) biomarker. METHODS: A high- sensitivity determination method was established using a moderate methyl esterification instead of methyl esterification of highly toxic diazo reaction. RESULTS: The standard curve regression linear equation of the method was: y=8460.5x-4758.2, the linear coefficient was 0.999 7, the minimum quantity concentration was 2.0 µg/L, the range of precision value was 0.81%-2.38%, and the average recovery of standard addition was 99.0%-102.9%. CONCLUSION: This method reduces the risk of traditional methyl esterification, improves the determination sensitivity compared with the GC-FPD method, and meets the determination requirement of TDGA.

[Determination of dimethyl ether in workplace air with gas chromatography].

OBJECTIVE: To develop determination of dimethyl ether in workplace air by GC. METHODS: Dimethyl ether were sampled with solvent desorption active carbon tube. The sampled carbon tube were desorbed by carbon tetrachloride, Elite-WAX column was used with temperature programmed from 40 to 90 degrees C, and the carrier gas programmed from 1.4 - 2.5 ml/min. RESULTS: There was a good linearity (r = 0.9999) over the concentration of 0-63.91 microg/L, detection limit can reach 0.75 microg/ml. CONCLUSION: This method proved to be accurate and sensitive, to meet the determination of the dimethyl ether in workplace air.

[Effect of occupational stress on ambulatory blood pressure].

OBJECTIVE: To explore the effect of occupational stress on ambulatory blood pressure. METHODS: 30 male healthy workers from the refrigerator assembly line in Henan province in China were investigated. Psychosocial work conditions were measured by using the Job Demand-control Model, the Effort-reward Imbalance Model questionnaires and Occupational Stress Measurement Scale. Ambulatory blood pressure(ABP) was measured by using mobile ABP monitor. The t test was utilized to analyze the difference of parameters of ABP monitoring between different groups of occupational stress and other variables scores. The stepwise regression analysis was used to analyse the effect of occupational stress factors on parameters of ABP. RESULTS: (1) As to stressors, systolic blood pressure variability (SBPV), mean arterial blood pressure variability (MABPV) and heart rate at 30 minute after work in workers with high role conflict score were significantly higher than those in workers with low score (P < 0.05). Workers with high skill utilization score had significantly lower mean systolic blood pressure (SBP) at 30 minute after work than workers with low score (P < 0.05). Diastolic blood pressure variability (DBPV) and heart rate variability (HRV) in workers with high decision latitude score were significantly higher than those in workers with low score (P < 0.05). Workers with high job psychological demands score had significantly higher SBPV, DBPV and MABPV than workers with low score (P < 0.05). Heart rate-pressure product(RPP) and SBPV in workers with high effort score were significantly higher than those in workers with low score (P < 0.05). Workers with low rewards score had higher mean heart rate and heart rate at 30 minute after work than workers with high score (P < 0.05). (2) For personalities, workers with high work locus of control score had significantly higher mean diastolic blood pressure (DBP) and mean arterial blood pressure (MABP) than workers with low score (P < 0.05). Workers with high patience score had significantly lower mean SBP at 30 minute after work than workers with low score (P < 0.05). Heart rate at 30 minute after work in workers with high organization commitment score was significantly lower than that in workers with low score (P < 0.05). (3) Concerning buffer factors, HRV in workers with high control strategies score were significantly lower than that in workers with low score (P < 0.05). Workers with low supervisor support score had higher RPP and MABPV than workers with high score (P < 0.05). (4) In the multiple stepwise regression, daily life stress affected SBPV (R2 = 0.12) and MABPV (R2 = 0.05), depression was related to DBPV at 30 minute after work (R2 = 0.15) and SBPV (R = 0.03), mental health was predictor of MABPV (R2 = 0.07) and negative affection was predictor of heart rate at 30 minute after work (R2 = 0.24). CONCLUSIONS: Occupational stressors, personality and social support have effect on parameters of ABP. Parameters of ABP monitoring could be used to evaluate occupational stress in the field research.