高效液相色谱法测定环境空气酰胺类化合物

高效液相色谱法测定环境空气中酰胺类化合物,采用多孔玻板吸收管采集环境空气中的酰胺类化合物,吸收液经0.22μm膜过滤后,经C18色谱柱分离,采用紫外检测器检测。丙烯酰胺、二甲基甲酰胺、二甲基乙酰胺的检出限分别为0.04μg/m3、0.000 2 mg/m3、0.000 2mg/m3（10 ml吸收液,采集15 L环境空气样品计）。高、中、低三种浓度三种酰胺类化合物的回收率区间为70.8%~90.2%,相对标准偏差范围小于9.6%。该方法操作简单,结果准确、可靠,适用于环境空气中酰胺类化合物的快速、准确监测。     

Rapid and sensitive headspace gas chromatographic method for cyanide determination in whole blood

We reported a simple and rapid headspace (HS) gas chromatographic (GC) assay for the determination of cyanide in human whole blood obtained from both cadaveric and intoxicated subjects. The poison was extracted from whole blood samples by HS technique after 10 min incubation at 80°C with a HCl (1N) acidic solution supplemented with 30 g L^?1 of sodium chloride and 10 mg L^?1 of isopropanol as internal standard. A SGE WAX capillary column (30 m × 0.32 mm ID × 0.5 µm df) was used. The Flame Ionization Detector (FID) was set at 250°C. The detection and the quantification limits were 0.02 and 0.2 mg L^?1, respectively. In the within-day study, the coefficients of variation for three different whole blood cyanide concentrations varied between 3.2 and 6.5%, whereas those in the day-to-day study varied between 4.8 and 6.3%. The assay was performed in less than 20 min per sample, which appears to be suitable for emergency toxicological tasks involved in diagnosis of cyanide poisoning.     

Screening of antibiotic residues in fresh milk of Kathmandu Valley,Nepal

The prevalence of two groups of antibiotics; namely penicillin and sulfonamides was studied in fresh milk available in Kathmandu Valley of Nepal. The milk samples (n = 140) were collected from three different sources; individual farmers, cottage dairies and organized dairies of Kathmandu valley. Qualitative and semi-quantitative analysis with rapid screening kits revealed that 23% samples were positive for antibiotic residues in the fresh milk for penicillin and sulfonamide groups (1–256 µg/kg). High performance liquid chromatography (HPLC) analyses detected 81% samples positive for amoxicillin (68–802 µg/kg), 41% for sulfadimethoxine (31–69 µg/kg), 27% for penicillin G (13–353 µg/kg), and 12% for ampicillin (0.5–92 µg/kg). Due to the precision and accuracy of liquid chromatography method, it detected more positive samples and consequently presented higher prevalence than the rapid screening kits. The antibiotic residues were found above the maximum residue limits that presented serious threat to consumer health and raised a serious concern regarding the implementation and monitoring of international regulations in developing countries.     

Chelating resin immobilized sawdust packed chromatographic column: Application to separation and preconcentration of lead ion

Naturally abundant rubber sawdust has been utilized as a stationary support, which after immobilization with a chelating polyelectrolyte (xylenol orange as counterion) gets converted into a suitable column packing material for isolation and enrichment of trace level target analyte, accurately detectable by the technique of differential pulse anodic stripping voltammetry. The sorbent is robust and re-usable in column-chromatography without showing any leaching and interference complications. Its unique lead ion selectivity from multielemental complex matrices (synthetic water sample, blood serum) at optimized column conditions (pH 2.5 and flow rate 0.5?mL?min^?1) mitigates the usual problems of intermetallic and readsorption effects. Effects of flow rate, pH, equilibration time, and other variables are reported. The system has advantageous feature to be used in a single-column ion chromatography with satisfactory performance. A modest attempt has been made to determine lead fractions in human blood serum samples on the bases of selective retention of ionic and labile fractions on complexing resin.     

Effect of Cd++ on germination,growth and active principles of Datura metel L.∗

The effects of Cd⁺⁺ concentration increment in soil and/or in atmosphere, on germination, growth and alkaloid contents of Datura metel L. were investigated. We observed a significant reduction of growth following addition of Cd⁺⁺ in soil. Minor effects on growth were evident when the plants were sprayed with CdCl₂ solution (10mgCd⁺⁺/l).

Scanning electron microscope observation showed stomata widely open and conspicuous cuticular striations in the foliar epidermis of polluted plants.

GLC analysis of extracts evidenced a significant variation in active principle content among plants undergoing different treatments.     

Speciation studies on simulated gastro‐intestinal digests of foodstuffs†

The factors affecting the solubilisation of metals during digestion of food have been examined in a two‐stage model system comprising simulated gastric and intestinal juices. The solubilisation of iron, copper and zinc was examined in digests of white and wholemeal bread. Zinc solubility was principally governed by pH and the simulated digestion had little additional effect. In contrast both iron and copper solubility were markedly affected by digestion of the bread. In the case of copper the enzymolysis increased solubility appreciably at neutral pH. All of the cadmium in a simulated gastric digest of canned crab meat was associated with soluble low molecular weight species of less than 1000 daltons. Cadmium solubility resulted from the acidic conditions of the digest rather than enzymatic solubilisation of binding proteins. Ninety percent of the cadmium in the digest became rebound to the insoluble fraction on adjustment to pH7.0. Subsequent simulated intestinal digestion increased the level of soluble cadmium to 20%; 1.0–1.5% was associated with soluble species in the range 26,000–37,000 daltons and 15.0–20.0% with soluble species of less than 3,000 daltons.     

加速溶剂萃取-固相萃取净化-超高效液相色谱串联质谱法测定土壤中11种全氟化合物

采用超高效液相色谱-串联质谱联用法（UPLC-ESI-MS/MS）,建立了分析土壤中11种全氟化合物（PFCs）的方法.以甲醇作为萃取剂,样品经加速溶剂萃取仪（ASE）萃取,固相萃取净化后,使用UPLC-ESI-MS/MS联用仪分析样品中11种PFCs.在6 min内就可快速稳定地将所选取的11种全氟化合物分离,且最低检测浓度为0.518—3.520 pg.g-1之间,这些化合物在土壤中的平均添加回收率在71.2%—119.2%之间.应用此方法测得宜兴市水稻土样品中所选取的PFCs含量为0.006—0.780 ng.g-1之间.     

高温燃烧水解-淋洗液在线发生离子色谱法同时测定煤中氟和氯

采用高温燃烧水解煤样-超纯水吸收装置,建立了高温燃烧水解-淋洗液在线发生离子色谱法同时测定煤中氟和氯的分析方法。系统、全面地考察了测定方法的影响因素,确定了最优高温燃烧水解预处理煤样和离子色谱法条件,并将该方法推广应用于飞灰、土壤和岩石的氟和氯含量检测,实验测定值与标准物质真实值误差能满足测定要求。     

水中痕量阿特拉津的测定方法研究

采用固相萃取与高效液相色谱结合的方法测定了水样中痕量阿特拉津的含量,研究了最佳固相萃取条件:选择洗脱液为乙腈,过样流速为5.0 mL/min。最佳的色谱条件:流动相为乙腈和水,温度为25℃,流速为1.0 mL/min,检测波长为222 nm。阿特拉津质量浓度在0.05～5 mg/L范围内线性关系良好,回归方程y=219.71x+2.2343,回收率平均值为98.46%,将该方法应用于实际环境水样的分析测定,操作简单,结果准确。