ABSTRACT
Background Diacetyl (DC) is widely used in the food flavoring industry and excessive occupational exposure to DC can cause serious respiratory diseases. However, there is no corresponding national standard method for the determination of DC in the air of workplace. Objective To establish a method for the determination of DC in workplace air by high performance liquid chromatography using 4-nitro-o-phenylenediamine (NPDA) as precolumn derivatization. Methods DC in the air of workplace was collected by solution absorption method. This experiment used NPDA as the derivatization reagent. By adjusting acidity of solution and optimizing concentration ration of DC/NPDA, derivatization temperature, and time, a method for the determination of DC in workplace air was proposed, and its performance indexes such as linearity, detection limit, and lower limit of quantification were obtained. Sampling efficiency was evaluated by relative comparison method, and sample stability was evaluated by sample preservation test. Accuracy and precision of the method were evaluated by standard addition recovery test with blank samples, and an interference test was carried out by adding standard samples. The established method was applied to actual samples to evaluate its adaptability. Results A combination of 60 °C for 2 h was selected for derivatization because a higher derivatization reaction temperature and a longer reaction time associated with a higher derivatization efficiency. The solution was separated by SB-C18 column (250 mm×4.6 mm, 5 μm) at 30 ℃, using a mixture of methanol and water (v/v, 65%/35%) as mobile phase with an elution flow rate of 1.0 mL·min−1, and was detected with a variable wavelength detector (λmax=257 nm) by qualitative analysis based on retention time and quantitative analysis based on external standard method. In terms of the proposed method, the linear range of detection was from 5 μg·L−1 to 2000 μg·L−1, with a correlation coefficient of 0.9999, and a detection limit of 1.3 μg·L−1, the quantitative detection of the lower limit was 4.3 μg·L−1, with a sampling volume V0 of 3.0 L, the minimum detection concentration was 4.3 μg·m−3, and the minimum quantitative concentration was 14.3 μg·m−3. The recovery rate was 99.1%-100.8%, the intra-batch precision was 0.5%-3.0%, and the inter-batch precision was 1.2%-2.0%. The average sampling efficiency of this method was 94.5%, and the sample could be stored at 4 °C for at least 14 d. The coexisting components in the air of the workplace did not interfere with the determination of DC. The DC content in the air of a flavor workplace was 5.86-8.85 mg·m−3. Conclusion A determination method for DC in workplace air by high performance liquid chromatography using NPDA as precolumn derivatization after being collected by 1.0% phosphoric acid absorbent is proposed and has the advantages of simple operation, high sensitivity, and good accuracy. With no DC loss and degradation, the method may satisfy the request for DC determination in the air of workplace.
ABSTRACT
Objective@#To establish a method for determination the S-phenylmercapturic acid in urine by dispersive solid-phase extraction using Humic Acid/Fe3O4 magnetic nanocomposite as adsorbent.@*Methods@#The 5 ml of urine samples were adjusted to pH 1.0 and extracted by Fe3O4@HA. Then the analytes were separated on EC-C18 capillary column and detected by HPLC-VWD. The S-phenylmercapturic acid was characterized by the retention time and quantified by peak area and external standard method.@*Results@#The standard curves of SPMA showed significant linearity between 0.04~1.00 mg/L (r=0.999 7) . The average recovery was 94.2%~102.4%. The intra-day and inter-day precisions (RSD) were 2.9~6.7% (n=6) and 3.1~7.5% (n=6) respectively. The detect limit of SPMA was 0.012 g/L (S/N=3) .@*Conclusion@#This method is simple, rapid, sensitive and accurate. It is applicable for determination of SPMA in the urine of works who were exposed to benzene.
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Objective@#To establish a method for determing the trichloroethylene(TCE)and trichloroethanol(TCOH)in blood samples by liquid-liquid extraction-gas chromatography with electron capture detector.@*Methods@#With this method,ether was used as extraction solvent and trichloromethane was used as an internal standard. The whole blood sample was extracted with ether, and dehydrated by anhydrous sodium sulfate. Then the analytes were separated on HP-5 capillary column(30m×0.32mm×0.15μm)and detected byECD.The retention time was for qualitative analysis and the internal standard was for quantitation.@*Results@#The standard curves of TCE and TCOH showed significant linearity between 95.5μg/L-7640.0μg/L(r=0.9997)and 19.0μg/L-1520.0μg/L(r=0.9992). The average recovery was 95.5%-103.6%.The intra-day and inter-day precisions(RSD)were 2.5%-6.8%(n=6)and 1.6%-4.3%(n=6) respectively. The detect limit of TCE and TCOH were 2.10 μg/L and 0.56μg/L(S/N=3)respectively.The blood can be kept 7 days at-20℃ refrigerator without significantly loss.@*Conclusion@#This method is proved to be simple,practical and highly sensitive. It can satisfy the request for the determination of blood samples of humans exposed to TCE.
ABSTRACT
To investigate hematopoiesis and cytogenetics changes in staff of interventional radiology.A total of 121 intervention radiation workers, 245 common radiation workers and 100 medical personnel (healthy control) without exposure to radiation were enrolled in the study. The peripheral lymphocyte chromosomal aberrations and micronucleus were detected, and the result of white blood cells examination was analyzed.Compared with common radiation group and healthy control group, decreases in white blood cells count, neutrophil ratio, and increase in lymphocyte ratio were observed in intervention radiation group (all<0.05). Intervention radiation group had higher chromosome aberration rate and micronuclear rate than common radiation group and healthy control group (all<0.05). Most common chromosome aberrations were dicentric chromosome, acentric ring, fragments and minute chromosome. Abnormal rates in chromosome aberration and micronucleus rates were increased with the rise of length of service, but no statistically significant difference was observed (>0.05).Long term exposure to ionizing radiation may lead to changes in the human hematopoietic system and cause human chromosome aberration, and the severity of such injuries may be associated with the dose of ionizing radiation.