Biological limit value for occupational exposure to N, N-dimethylacetamide / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish Biological Limit Value (BLV) for N, N-dimethylacetamide (DMAC).</p><p><b>METHOD</b>201 workers in 3 spandex factories exposed to DMAC were recruited. Air samples were collected using personal air samplers, and urine samples from each works were collected at the end of shift at end of workweek. The urinary metabolite NMAC and air samples of DMAC were determined by gas chromatography (GC). Percentile and relative internal exposure (RIE) were analyzed and proposed a BLV for DMAC.</p><p><b>RESULTS</b>The number of workers who exposure to DMAC below OELs were 133 (66.2%) among 201 workers monitored. Geometric mean (range) concentration of DMAC in air was 19.4 (0.40 ∼ 300.12) mg/m(3), and that of NMAC in urine was 23.7 (1.30 ∼ 189.42) mg/g Cr. A linear correlation was found between the personal air DMAC and creatinine-adjusted NMAC levels in urine collected at the end of shift at end of workweek (F = 188.872, R(2) = 0.487,P < 0.001). The relationship can be described by the equation Log (NMAC mg/g Cr) = 0.685 + 0.455 log (DMAC mg/m(3)). According to the equation the current China OELs value of 20 mg/m(3) would lead to a mean NMAC concentration of 18.92 mg/g Cr. The 90th percentile biomonitoring result below 20 mg/m(3) 8-hour TWA is 23.9 mg MMAC mg/g Cr, and that of NMAC in urine calculated by relative internal exposure (RIE) was 19.0 mg/g Cr.</p><p><b>CONCLUSION</b>A BLV of 20 mg/g Cr NMAC in urine at the end of shift at end of workweek for DMAC was recommend by reference to official values from other countries.</p>

The analysis of urinary N-methylacetamide by GC-NPD with a direct injection / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish a method to detect N-methylacetamide (NMAC) concentration in urine of workers occupationally exposed to NMAC with directly injecting the sample into capillary gas chromatography.</p><p><b>METHODS</b>After frozen urine samples were isolated from precipitation by centrifugation, the aliquot of supernatant was pretreated by protein precipitation with dilution of methanol. The methanol supernatant was separated by Polyethylene Glycol (PEG) capillary columns and detected by nitrogen phosphorous detector (NPD).</p><p><b>RESULTS</b>Good linearity was obtained in the concentration range of 1.0 ∼ 250 mg/L. The correlation coefficient was 1.0000. The minimum detection limit of NMAC in urine was 0.2 mg/L. The method recovery rates were 96.0% ∼ 99.4% at three different concentrations. The mean recovery rate was 97.8%. The relative standard deviations (RSD) of intra- and inter-day were between 1.5% ∼ 3.4%.</p><p><b>CONCLUSION</b>The method was simple, rapid, selective and sensitive and was applicable to detect the urinary NMAC concentration for monitoring occupational exposure levels.</p>

The impact of N, N-dimethylacetamide on the health of workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the hepatic toxicity and the exposure biomarkers of N, N-Dimethylacetamide.</p><p><b>METHODS</b>One hundred forty five objects were chosen by stratified random sampling method. The investigation was performed using questionnaire and physical examination. The air concentrations of DMAC in the workshops were monitored. The urine samples were collected and analyzed after work everyday or at the weekend. The correlation between the air concentrations of DMAC in the workshops and the concentrations of urinary NMAC wee analyzed by regression.</p><p><b>RESULTS</b>The air concentration of DMAC in the spinning workshop was higher than others. The morbidity of abnormal hepatic function was 12.4%, 61.1% of workers with abnormal hepatic function appeared in one year after exposure to DMAC in the workshops ( r=0.44, P<0.01).</p><p><b>CONCLUSION</b>The abnormal heptic function was found in workers exposed to DMAC for short period. The concentration of urinary NMAC can serve as the exposure biomarker of DMAC.</p>

Determination of trimethyltin chloride in urine by headspace-gas chromatography / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish a detection method for trimethyltin chloride in urine by the Head space-GC.</p><p><b>METHOD</b>After derivatizing trimethyltin chloride, the urines was separated by the head space-gc, and then the trimethyltin chloride detected qualitatively and quantificationally.</p><p><b>RESULTS</b>In the concentration range of 0.02 ∼ 0.40 mg/L urinary trimethyltin chloride, showed a quadratic, r = 0.9992, detection limit was 0.005 mg/L, the relative standard deviation was 1.9% ∼ 2.5%, recovery was 92.0% to 100%, the urine samples can be saved at least 90 days in -18°C refrigerator.</p><p><b>CONCLUSION</b>The instrument, reagents involved in the detection require low, the operations to processing samples are simple, high sensitivity, less interference, good reproducibility, and suitable for quantitative and qualitative analysis, convenient to promotion.</p>

Investigation on dermal contamination among workers occupationally exposed to dimethylformamide / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish a method for the determination of dimethylformamide (DMF) and investigate dermal contamination and absorption among workers occupationally exposed to DMF.</p><p><b>METHOD</b>37 workers exposed to DMF were divided randomly into two groups. DMF was washed down by isopropyl alcohol in A group (16 workers) and water in B group(21 workers).Gas chromatography was used for the quantification of dermal contamination and N-methylformamide(NMF) in urine, correlative study was done between them.</p><p><b>RESULTS</b>DMF could be detected in all samples in A group, but could not be detected in B group. The miscellaneous peaks could be completely separated from the DMF peak in the sample spectrum, without manual inference. The highest degree of total dermal contamination was observed in wet spinning workshop [(2.84 +/- 1.31) mg], postprocessing workshop [(2.50 +/- 0.95) mg] and dry spinning workshop [(1.95 +/- 0.61) mg] were lower. The respiratory cumulative exposure dosages were 351.3, 201.3 and 135.2 mg respectively. The average DMP concentration in air of the third printing processing workshop, the dry spinning workshop and the wet spinning workshop was 60.2, 89.6, 156.4 mg/m3 respectively, and the respiratory tract contamination in the workers of the three workshops were 135.2, 201.3 and 351.3 mg respectively. There was statistical independence between the quantification of total dermal contamination and NMF in urine (r = 0.176, P > 0.05).</p><p><b>CONCLUSION</b>Isopropyl alcohol is the effective washing solvent.When the concentration of DMF in workplace air is above the occupational exposure limit, respiratory tract absorption is the principal pathway of DMF absorption,but dermal contamination of DMF should not be ignored.</p>