الملخص
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.
الملخص
Objective:To analyze the curative effect of Ligasure hemorrhoidectomy combined with knot-free barbed wire for patients with mixed hemorrhoidectomy in day ward.Methods:Retrospectively analyzed the case data of 126 patients, aged from 22 to 76 years (average age was 45.8 years), with grade Ⅲ and Ⅳ mixed hemorrhoids in the day ward of Beijing Friendship Hospital, Capital Medical University from January 2021 to December 2021, including 53 male cases and 73 female cases. According to the operation method, all patients were assigned to the observation group ( n=63) and the control group ( n=63). In the observation group, patients were operated with Ligasure hemorrhoidectomy combined with knot-free barbed wire. In the control group, patients underwent the Milligan-Morgan. Normal distribution of measurement data were expressed as mean±standard deviation ( ± s), and t test was used for comparison between groups. Count data were compared by Chi-square test or continuity correction Chi-square test.The operation time, intraoperative bleeding, postoperative pain, postoperative complications and hospitalization expenses were compared between the two groups. Results:The operation time and intraoperative blood loss in the observation group were significantly lower than those in the control group ( t=-7.74, P<0.001; t=-7.07, P<0.001). There was no significant difference in visual analogue scale between the two groups on the 1st, 3rd, 7th days after operation( t=-1.47, P=0.144; t=-0.32, P=0.749; t=-0.34, P=0.732). There were no significant differences in postoperative urinary retention, postoperative bleeding and perianal edema between the two groups ( χ2=0.34, P=0.559; χ2=1.81, P=0.179; χ2=1.92, P=0.165). However, the total incidence of complications in the observation group was significantly lower than that in the control group, the difference was statistically significant ( χ2=4.15, P=0.042). Hospitalization cost of observation group was higher than control group ( t=4.73, P<0.001). Conclusions:For patients with grade Ⅲ and Ⅳ mixed hemorrhoids in the day ward, Ligasure hemorrhoidectomy combined with knot-free barb wire can significantly shorten the operation time, reduce intraoperative blood loss, and lower the incidence of postoperative complications. It is safe and effective, which can meet the hemorrhoidectomy’s requirements of rapid, efficient and safe in the day ward.
الملخص
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.
الملخص
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.
الملخص
Objective To explore the clinical result and complications of noncyclic-PPH surgery in treating internal hemorrhoids.Methods In this study,we evaluate the clinical outcome,such as clinical efficacy,operation time,length of hospital stay,postoperative pain degree and incidence of complications in 120 hemorrhoid patients,randomly divided into control group (60 cases) and observation group (60 cases)based on digital table method,receiving respectively noncyclic-PPH,or PPH (procedure for prolapse and hemorrhoids).Results Two groups were similar in average operation time and average length of hospital stay (P ＞ 0.05).The postoperative VAS score at each time point,was significantly lower in noncyclic-PPH group than the control group (P ＜ 0.05).Non-cyclic PPH group were also significantly lower in postoperative complications than the control group (P ＜ 0.05).Conclusion Compared with PPH surgery,patients with noncyclic-PPH have fewer pain complications or trauma.