[Ion chromatography for the determination of n-butylamine in the workplace air].

Objective: To establish a method for the determination of n-butylamine in the air of the workplace by ion chromatography. Methods: In February 2022, on-site sampling was carried out using an atmospheric sampler. N-butylamine was adsorbed by a neutral silica gel tube and then performed for qualitative and quantitative determination by ion chromatography after ultrasonic desorption with 10 mmol/L sulfuric acid solution. Results: The linear range of the method was 0.0375-100.0 µg/ml, the linear equation of the standard curve was y=0.0713x-0.0327, the correlation coefficient was 0.9992. The detection limit of the method was 11.25 µg/L, and the lower limit of quantification was 37.50 µg/L, the lowest quantitative concentration was 0.025 mg/m(3) (in term of sampling 7.5 L). The average desorption efficiency of the method was 91.50%-95.38%, the precision was 1.10%-2.30%, the standard recovery was 83.83%-100.02%, sampling efficiency was 100.00%. Conclusion: This method is fast, sensitive and accurate, and can be used for the determination of n-butylamine in the air of workplace.

[Determination of misoprostol in workplace air by high performance liquid chromatography].

Objective: To establish a high performance liquid chromatography method for the determination of misoprostol in workplace air. Methods: From February to August 2021, the misoprostol in the workplace air was collected by glass fiber filter membrane, and theeluent was separated by C18 liquid chromatography column, determined by UV detector, and quantified by external standard method. Results: The quantitative lower limit of misoprostol determination method was 0.05 µg/ml, and the lowest quantitative concentration was 1.4 µg/m(3) (calculated by collecting 75 L air sample). The concentration of misoprostol has a good linear relationship between 0.05 to 10.00 µg/ml. The relative coefficient was 0.9998. The regression equation of the standard working curve was y=495759x-45257. The range of average recovery rates were from 95.5% to 102.8%. The intra-assay precision of the method was 1.2%-4.6%, and the inter-assay precision was 2.0%-5.9%. The samples could be stored stably for 7 days at 4 ℃. Conclusion: The high performance liquid chromatography method for the determination of misoprostol has high sensitivity, good specificity and simple procedure of sample pretreatment. It is suitable for the detection of misoprostol in the workplace air.

[Evaluation of the determination of hydrogen sulfide in the air of workplace by the detection tube method].

Objective: To evaluate the accuracy and applicability of detection tube method for quantitative detection of hydrogen sulfide in workplace air. Methods: In September 2021, the lower limit of quantification, accuracy, precision, environmental factors, interfering gases and other performance indicators of the method for determining hydrogen sulfide in the air of workplace were verified by the detection tube, and the results were compared with those of GB 11742-89 "Standard method for hygienic examination of hydrogen sulfide in air of residential areas-methylene blue spectrophotometric method" to evaluate the application effect of the detection tube method for quantitative detection of hydrogen sulfide in workplace air. Results: There was no significant difference in the results of 2.83 mg/m(3), 4.25 mg/m(3) and 17.00 mg/m(3) hydrogen sulfide concentration between the two methods (P>0.05) , but there was significant difference in the results of 8.50 mg/m(3) concentration (P<0.05) . The lower limit of quantification of hydrogen sulfide in workplace air was 2.83 mg/m(3), the accuracy was 96.0%-111.0%, and the precision was 0.70%-6.64%. Under the condition of 4 ℃, the measured results decreased by 3.39%-13.10%. When the humidity was 50%-80%, the relative error of the average measured value was -1.67%-4.44%. Interference gases that may exist in the workplace (including carbon dioxide, carbon monoxide, mercaptans, nitrogen oxides, sulfur dioxide, etc.) did not interfere with the results of the test tube. Conclusion: The accuracy and precision of the detection tube method meet the detection requirements. The method is simple, rapid and easy to be popularized, and can be used for the rapid detection of hydrogen sulfide gas concentration in the workplace.

[Research progress in detection methods of amine compounds in air].

Amine compounds are important nitrogen-containing compounds in the atmosphere. Most organic amines are volatile and highly toxic. They can enter the human body through respiratory and skin contact in the workplace. Long-term exposure can cause headache, dizziness, nausea, vomiting, diarrhea and other symptoms, even damage the nervous system and cardiovascular system. With the widespread application of amine compounds, people may also be exposed to low doses of amine compounds in daily life. In order to better assess the harm caused to human, this article reviews the research progress of amine limits and detection methods.

[Ion chromatography for the determination of ethylamine in the workplace air].

Objective: To establish a method for the determination of ethylamine in the air of the workplace by ion chromatography. Methods: In August 2020, ethylamine in the air of the workplace was adsorbed by a basic silica gel tube, and ultrasonically desorbed with a 1 mmol/L sulfuric acid solution, and then qualitatively and quantitatively determined by ion chromatography. Results: The linear range of the method was 0.014-50 µg/ml, and the linear equation of the standard curve was y=0.1243x+0.0429, the correlation coefficient was r=0.9997. The detection limit of the method was 4.29 µg/L, and the lower limit of quantification was 14.29 µg/L. The lowest quantitative concentration was 0.012 mg/m(3) (in term of sampling 6.0 L) . The average desorption efficiency of the method was 97.31%, the precision was 1.00%-1.68%, and the standard recovery rate was 96.33%-99.61%. Conclusion: This method is fast, sensitive and accurate, and can be used for the determination of ethylamine in the air of workplace.

[Research of the certified reference material of mecury in lyophilized bovine blood].

Objective: To develop a reference material for the analysis of mercury in freeze-dried bovine blood. Methods: The whole blood of the bovine was collected, mercury standard solution was added, After mixing, packaging and freeze-drying. Two concentration levels of reference materials were prepared. The homogeneity and stability were evaluated by t-test and F-test methods respectively. The uncertainty in preparation, long-term stability, short-term stability and fixed value were evaluated Evaluation and assignment of reference materials. The research products were fixed value and were analyzed by two methods and fixed value in 9 laboratories and the uncertainty during development was analyzed. Results: The reference material has good uniformity and can be kept stably for 12 months at -20 ℃; When transported at ≤35 ℃, the quantity value is stable within 7 days; After re dissolution, it can be stored at 4 ℃ for 5 days; The values are 9.4 respectively µg/L and 29.2 µg/L, and the uncertainty is ±1.1 respectively µg/L and ±2.3 µg/L (k=2) . Conclusion: The indexes of reference materials for mercury composition analysis in freeze-dried bovine blood meet the requirements of technical specifications and have certain application value.

[Membrane sampling for the determination of chlorothalonil in the air of workplaces-solvent analysis-Gas Chromatography].

Objective: To establish a method for the determination of chlorothalonil in air by filtration membrane sampling, solvent elution and gas chromatography. Methods: PTFE filter was used for sampling, eluted with dichloromethane, separated by DB-5 capillary column, and determined by FID. Results: The standard curve was used for quantitative detection, and the correlation of chlorothalonil in the range of 15 µg/ml-300 µg/ml, R(2)=0.9999. The detection limit of this method was 1.70 µg/ml and the lower quantitative limit was 5.70 µg/ml. The minimum detected concentration was 0.045 mg/m(3) (75L air sample was collected) . The recovery rate was 90.14%-91.81%. The precision of the same batch was 1.5%-1.8%, and that of different batches was 2.3%-3.8%. The sampling efficiency can reach above 95%; The samples can be stored for 14 days at room temperature. Conclusion: The results show that the method of filtration membrane sampling-solvent elude-gas chromatography is suitable for the determination of chlorothalonil in the air.

[Development of the certified reference material of cadmium in human urine (freeze-dried)].

Objective: To develop the certified reference material of cadmium in human urine (freeze-dried) . Methods: Urine were collected from normal human, and then the urine samples were prepared by adding standard, mixing, packing and freeze-drying. After homogeneity test and stability test, the urine samples were determined by two methods in seven independent laboratories, the uncertainty of the certified reference material was evaluated. Results: Take at least 0.20 ml solution of the certified reference material per use, and the homogeneity is good. The freeze-dried materials can be kept stable for 12 months at ≤4 °C, and the re-dissolved reference materials can be stabilized for 7 days at 4 °C. The standard values and uncertainty of the two levels were (5.34±0.34) µg/L and (15.47±0.72) µg/L, respectively. Conclusion: The standards met the requirements of national standards, and can be used to verify the methods of detecting cadmium in human urine and to detect the samples.

Biological Characteristics and Molecular Mechanisms of Fludioxonil Resistance in Fusarium graminearum in China.

Fusarium graminearum is the primary causal agent of Fusarium head blight (FHB) of wheat. The phenylpyrrole fungicide fludioxonil is not currently registered for the management of FHB in China. The current study assessed the fludioxonil sensitivity of a total of 53 F. graminearum isolates collected from the six most important wheat-growing provinces of China during 2018 and 2019. The baseline fludioxonil sensitivity distribution indicated that all of the isolates were sensitive, exhibiting a unimodal cure with a mean effective concentration for 50% inhibition value of 0.13 ± 0.12 µg/ml (standard deviation). Five fludioxonil-resistant mutants were subsequently induced by exposure to fludioxonil under laboratory conditions. Ten successive rounds of subculture in the absence of the selection pressure indicated that the mutation was stably inherited. However, the fludioxonil-resistant mutants were found to have reduced pathogenicity, higher glycerol accumulation, and higher osmotic sensitivity than the parental wild-type isolates, indicating that there was a fitness cost associated with fludioxonil resistance. In addition, the study also found a positive cross resistance between fludioxonil, procymidone, and iprodione, but not with other fungicides such as boscalid, carbendazim, tebuconazole, and fluazinam. Sequence analysis of four candidate target genes (FgOs1, FgOs2, FgOs4, and FgOs5) revealed that the HBXT2R mutant contained two point mutations that resulted in amino acid changes at K223T and K415R in its FgOs1 protein, and one point mutation at residue 520 of its FgOs5 protein that resulted in a premature stop codon. Similarly, the three other mutants contained point mutations that resulted in changes at the K192R, K293R, and K411R residues of the FgOs5 protein but none in the FgOs2 and FgOs4 genes. However, it is important to point out that the FgOs2 and FgOs4 expression of all the fludioxonil-resistant mutants was significantly (P < 0.05) downregulated compared with the sensitive isolates (except for the SQ1-2 isolate). It was also found that one of the resistant mutants did not have changes in any of the sequenced target genes, indicating that an alternative mechanism could also lead to fludioxonil resistance.

Improving the quality of rooster semen frozen in straws by screening the glycerol concentration and freezing rate.

1. This study examined different glycerol concentrations (GC) and freezing rates to improve the quality of rooster spermatozoa frozen in straws, and to determine the effect of varying GC on post-thawed spermatozoa quality, as evaluated by fertility and hatchability.2.The experiment included two tests. In test 1, rooster semen straws containing 2, 4, 6, 8 and 11% glycerol were put in a rack (nine tiers with a 1 cm interval between every two tiers, 1 to 9 cm above liquid nitrogen (LN) source), and gradually frozen. The semen straws located in different tiers experienced different temperatures and freezing rates. The straws were then thawed and live sperm numbers determined. In test 2, rooster semen straws containing 2, 4, 6, 8 and 11% glycerol were put on optimal tiers (identified in test 1) for freezing, and stored at -196°C. Hens were inseminated with the frozen semen (post-thawed and glycerol removed, about 4.0 × 108 sperm per hen), and eggs incubated.3. The numbers of live sperm in the 11% glycerol group was higher than that in 2, 4 or 6% glycerol group (P < 0.05) for the semen straws on tiers 1 to 9, while that on tiers 1 to 5 was lower than that on tier 6 to 8 (P < 0.05). GC, freezing rate and the interaction between GC and freezing rate had a significant effect on live sperm numbers (P < 0.01). The highest fertility was in the 6% glycerol group and occurred on day 5 after insemination. The lowest fertility occurred in the 2% glycerol group on day 10 after insemination.4. The optimal combination was 11% glycerol in straws located 6 cm above the LN surface (on tier 6). The 6% glycerol group achieved the highest fertility (77.6%), which surpassed that reported in recent years.

[Status analysis of standard methods for detecting metals and metalloids in the air of workplace in China].

To provide basis for improving the detection standard methods and improve the quality and applicability of the occupational health detection standard methods. This paper is based on occupational health standards and experimental data at home and abroad. Analysis the detection standard methods of metal and metalloid in the air of workplace through data collection, investigation and experiments.

[Determination of mifepristone in workplace air by ultra-performance liquid chromatography].

Objective: To establish an ultra-high performance liquid chromatography method for the determination of mifepristone in the air of workplaces. Methods: From January to July 2018, glass fiber filter membrane was used to collect mifepristone in the workplace air, eluted with acetonitrile/water solution, and determined by ultra-high performance liquid chromatography-UV method. Results: The detection limit of mifepristone determination method was 0.005 µg/ml, the lower limit of quantification was 0.015 µg/ml, and the lowest detection concentration was 0.14 µg/m(3) (calculated by collecting 75 L air samples) . The concentration of mifepristone has a good linear relationship between 0.015-40.24 µg/ml, r=0.9999. The accuracy and elution efficiency of the method were calculated based on the recovery rate, ranging from 92.7% to 100.0%. The average sampling efficiency was 99.6%-100.0%. The intra-assay precision of the method was 0.92% to 5.41%, and the inter-assay precision was 0.89% to 6.25%. The sample could be stored stably for 3 days at 4°C. Conclusion: The ultra-high performance liquid chromatography method for determination of mifepristone is easy to operate, and its indicators meet the requirements of GBZ/T 201.4-2008 "Guidelines for the Establishment of Occupational Hygiene Standards Part 4: Methods for Determination of Chemical Substances in Workplace Air", which is suitable for the detection of mifepristone in the air of the workplace.

[Determination of N-[4- (4-aminobenzyl) -phenyl] acetamide hemoglobin adduct in blood by ultra performance liquid chromatography-tandem mass spectrometry].

Objective: To establish the method for the determination of N-Acetyl-4, 4'-diaminodiphenylmethane (AcMDA) adduct in the hemoglobin by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) . Methods: The 20 mg hemoglobin sample was weighed into a 15 ml centrifuge tube, adding 20 µg/L internal standard solution AcMDA-D8 10 µl, then hydrolyzed with 1 ml 0.1 mol/L sodium hydroxide solution at 37°C for 0.5 hours, extracted with dichloromethane and concentrated by vacuum concentrator. The residue was dissolved in acetonitrile and detected by UPLC-MS/MS, then quantitative by internal standard method. Results: The linearity of the method was good at the range of 0.05-25.00 µg/L with a correlation coefficient of 0.9996, the detection limit (LOD) and limit of quantitation (LOQ) were 0.07 and 0.2 ng/g Hb, respectively. The recovery rate was ranged from 91.0%-95.4%; the relative standard deviation (RSD) of intra-and inter-batch precision were 4.5%-6.3% and 3.7%-4.4%, respectively. Conclusion: The determination method meet the requirement of GBZ/T 210.5-2008.

[Determination of tantalum and tantalum pentoxide in the air of workplace by inductively coupled plasma optical emission spectrometry].

Objective: To establish the method for determination of tantalum and tantalum pentoxide in the air of workplace by inductively coupled plasma optical emission spectrometry (ICP-OES). Methods: The tantalum and tantalum pentoxide in the workplace air were collected by filter membrane and then digested by microwave digestion apparatus in the mixed solvents (HNO(3)∶HF=3∶1) ,diluted to 50 ml and detected by ICP- OES. Results: The linearity of tantalum was good at the range of 0.0~100.0 µg/ml with a correlation coefficient of 0.9997, the LOD and LOQ were 0.04 µg/ml and 0.14 µg/ml, respectively. The recovery was ranged from 83.1%-87.8%; the RSD of intra-and inter-batch precision were 0.2%-1.0% and 1.1%-2.4%, respectively. The recovery was ranged from 87.4%-93.3%; the RSD of intra-and inter-batch precision were 0.5%-1.5% and 1.3%- 1.8%, respectively. Conclusion: The determination method meet the requirement of analysis and apply to the determination of tantalum and tantalum pentoxide in the air of workplace.

[Determination of tungsten and insoluble compounds in the air of workplace by ICP-OES].

Objective: To establish the method for determination of tungsten and insoluble compounds in the air of workplace by inductively coupled plasma optical emission spectrometry (ICP-OES) . Methods: The tungsten and insoluble compounds were digested by microwave digestion apparatus using nitric acid and hydrofluoric acid, detected by ICP-OES. Results: The linearity of tungsten and insoluble compounds (as tungsten) were good at the range of 0.16-100.0 µg/ml, the minimum quantitation concentration was 0.11 mg/m(3), the recovery was ranged from 81.9%-97.1%, the RSD of intra-and inter-batch precision were 0.5%-2.5% and 1.2%-4.4%, respectively. Conclusion: The determination method meet the requirement of analysis and apply to the determination of tungsten and insoluble compounds in the air of workplace.

[Development of ethylene glycol Samples in silicone tubes and their application in inter-laboratory comparison].

Objective: To development of ethylene glycol samples in silicone tubes, and the samples were applied to inter-laboratory comparison, through it to evaluate the detection capacity of occupational health testing laboratories. Methods: Three content levels of ethylene glycol samples in silicone tubes were prepared, and the homogeneity and stability of samples were investigated, the results were statistically analyzed. A robust statistical four-point distance method was used to calculate the results submitted by each participant laboratory and the test capability of the laboratory was assessed by the z-score method. Results: The statistic of the homogeneity of ethylene glycol samples in silicone tubes were less than the critical value (P>0.05) , and the samples were stable at room temperature for one month. The satisfactory rate of comparison between 204 laboratories was 88.24%. Conclusion: The homogeneity and stability of the ethylene glycol samples in the silicone tubes can meet the requirements of proficiency testing and can be used for laboratory comparison. Most of the laboratories that participated in the comparison had the ability to detect ethylene glycol.

[Analysis on occupational health laboratories' proficiency testing program for determination of bovine blood lead and urinary cadmium].

Objective: To analyze the results obtained from the proficiency testing program for determination of bovine blood lead and urinary cadmium, so as to evaluate the proficiency of the laboratories, and improve the detection and quality control capability of occapational health laboratory. Methods: Prepared 3 levels of lead samples with bovine blood as base material, taking Technical Norm of Primary Reference Material as Operating standard, 60, 80, 180 µg/L were used as the standard concentration. All samples were made for 200 bottles. Normal urine were used to prepared 3 levels of cadmium samples with 5.0, 7.0, 10.0 µg/L as standard concentration, then 3 level of samples were made for 200 bottles respectively. Blood lead and urinary cadmium samples were sent to each laboratory in the form of sample pairs. One-way ANOVA was used to investigate the homogeneity. The results of each laboratory were statistically analyzed by robust statistical method, and the detection ability of the laboratory was evaluated by the Z ratio score method. By consulting the test reports and original records of each participating laboratory, the reasons for the unsatisfactory results were analyzed. Results: The statistical F of the uniformity of blood lead 1.42, 1.37 and 2.85, F<3.13, P were 0.294, 0.314 and 0.059, respectively in 31 labs. There is no statistical significance in the difference of blood lead (P>0.05). And urine cadmium was less than the critical value (P>0.05). In all, 31 laboratories participated in the test of blood lead, and 28 loboratories paticipated in urine cadmium verification. The statistical F of the uniformity of urinary cadmium 1.90, 1.35 and 1.19, F<3.13. The homogeneity of the samples were in accordance with the requirements of proficiency testing program. The satisfactory rate of the results for blood lead was 84% (26/31) , and the satisfactory rate of urinary cadmium was 93% (26/28) . In the test of blood lead, 21 of the 31 laboratories were controlled by the standard material method. Totally, 20 of them get an satisfactory level, the rate was 95%. Conclusion: Most of the laboratory test results were satisfactory, which showed that the detection capability for blood lead and urine cadmium was good. The main causes of unsatisfactory results were detection methods, tools of quality control ortraceability standards.

[Determination method of barium sulfate in the air of workplace].

Objective: To establish the method for determination of barium sulfate in the air of workplace. Methods: The barium sulfate was collected by dichloride ethylene filter membrane and then processed by alkali fusion method. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used for the detection of barium sulfate. Results: The sampling efficiency was 100%, the linearity of ICP-OES was good at the range of 0.1~100.0 µg/mL, the recovery was ranged from 93.0%~97.8%, the RSD of intra- and inter-batch precision were 3.7%~7.6% and 4.7%~8.8%, respectively. Conclusion: The sampling method and determination method meet the requirements of analysis and apply to the collection and determination of barium sulfate in the air of workplace.

[Discussion on calculation method of detection limit and quantitative limit of occupational health biological monitoring method].

Objective: To discuss calculation method of detection limit and quantitative limit of occupational health biological monitoring. Methods: The detection limit and the quantitative limit of phenyl glyoxylic acid and Mandelic acid were calculated by using three different methods of IUPAC, NIOSH and OSHA respectively. Results: The IUPAC, NIOSH and OSHA methods were used to calculate the detection limit and the quantitative limit of the phenyl glyoxylic acid and Mandelic acid, and the results are different. Conclusion: To calculate the detection limit and quantitative limit of occupational health biological monitoring methods, the standard curve method is adopted to ensure that the rate of detection in the vicinity of detection limit and more than 75% of the quantitative limits are used.

[Optimization of ion selective electrode method in detection of urinary fluorine].

Objective: To optimize the ion selective electrode method of measuring urinary fluorine in WS/T 30-1996. Methods: The volume of 5 mol/L NaOH solution was fixed to confect the TISAB buffer solution. The samples were prepared by mixing 5 ml urine and equal volume of TISAB solution. Fluorine electrode and calomel electrode was used to test. When the potential value changed less than ±0.5 mV in one minute, it could be recorded. The standard curve method was selected as a quantitive method. Results: The linear range of this method was 0.07~50.0 mg/L, E=238.96-57.50lgC, r=0.999 8. The LOD and LOQ were 0.02 mg/L and 0.07 mg/L (with 5 ml urine) , respectively. The RSD of intra -and inter-batch precision were 0.80%~2.82% and 2.17%~2.86%, respectively. The recovery rate was 102%~107%. The urine sample could be preserved stably for 14 days at room temperature, and for 30 days at 4 ℃ and -20 ℃. Conclusion: In this method, the preparation process of TISAB buffer solution was simplified, and the linear range was expanded. It could meet the needs of occupational population detection.