Selenium determination in mother and child's hair by electrothermal atomic absorption spectrometry

A method for the selenium determination in a mother and her child's hair using palladium as a chemical modifier was optimized. The sample was digested with nitric acid and hydrogen peroxide and diluted to 5 ml. To achieve complete mineralization the samples were ashed at 1200 degrees C in the presence of palladium as a chemical modifier. The optimum atomization temperature was 1900 degrees C. The precision and accuracy of the method were studied using the reference material CRM 397. Results of calibration using aqueous standards and the standard addition method were compared. The method was applied to the selenium determination in 30 samples of the mother's and child's hair. The levels found were 0.54 +/- 0.34 microgram/g for mother's hair and 0.77 +/- 0.25 microgram/g for child's hair.     

Quantitative determination of cocaine and heroin by Fourier transform infrared spectrophotometry

Cocaine hydrochloride salt (HCl) and heroin HCl were determined quantitatively by choosing a carbonyl absorption peak as the analytical peak and measuring absorbance versus concentration in standard KBr pellets. The effect of various additives and diluents such as starch, sugars, mannitol, caffeine, and procaine was also studied. Methods were devised to correct for interference contributions based on spectral subtraction of the interfering component or subtraction of the interfering spectral contribution based on absorbance ratios with a noninterfering spectral peak. In mixtures containing both the free base and the hydrochloride salt, the most satisfactory method for determining the concentration was by area integration of the two carbonyl peaks.     

用硅藻土提取肝脏中安定的方法研究

目的　建立以亲水性固相材料硅藻土为支持物分离提取肝中安定。方法　取 1 0 g肝匀浆用 6%高氯酸沉淀蛋白 ,离心 ,取上清液加入硅藻土柱中 ,用二氯甲烷洗脱。洗脱液 5 0℃水浴挥干后 ,用 4 0ml 1 0mol/L的盐酸溶解 ,测定其紫外二阶导数光谱。结果　提取率达 91 0 % ,变异系数 2 5 % ,检出限 0 2 5 μg/ g ,线性范围0 5— 5 0 μg/mL。 结论　该方法操作简单、实用 ,杂质含量低 ,可以作为法医毒物分析的常规方法     

Experimental designs in the optimisation of ultrasonic bath-acid-leaching procedures for the determination of trace elements in human hair samples by atomic absorption spectrometry

Experimental designs were used for the optimisation of acid-leaching procedures assisted by ultrasonic energy for the extraction of Ca, Cu, Fe, Mg, Mn and Zn from human hair samples. A Plackett-Burman 2(7) x 3/32 design for seven factors ([HNO3], [HCl], [H2O2], acid/oxidant solution volume, exposure time to ultrasounds, temperature of the ultrasonic bath and hair particle size) was used in order to choose the variables affecting the acid-leaching process. The variables [HNO3], [HCl] and temperature of the ultrasonic bath were found to be the most important parameters for the acid-leaching procedure, and these variables were optimised by a response surface design (central composite design 2(3) + star) which involved 16 experiments. Optimum values in the 3.7-4.2 M range were found for [HNO3], while optimum values between 3.0 and 3.5 M were found for [HCl]. The optimum temperature of the ultrasonic bath was between 80 and 90 degrees C. An acid digestion induced by microwave energy (details given) was used to obtain the total metal concentration and also for comparative purposes. Ca, Cu, Fe, Mg and Zn were measured by flame atomic absorption spectrometry (FAAS) using a conventional air/acetylene flame, while Mn was determined by electrothermal atomic absorption spectrometry (ETAAS) under optimised conditions. Two different reference materials, IAEA-085 International Atomic Energy Agency, Monaco) and NIES No. 13 (National Institute for Environmental Studies, Japan), with certified metal contents for some of the elements investigated, were used in order to verify the accuracy of the methods.     

The determination of phoxim in cadaveric material by gas-liquid chromatography]

The developed gas-liquid chromatographic procedure for forensic chemical detection and measurement of phoxim in cadaveric material permits the detection in 25 g of an organ of 44 to 52% of added phoxim. The threshold of phoxim measurement in 100 g of the liver is 0.04 mg, the least volume of phoxim detectable being 0.02 g. The developed gas-liquid chromatographic technique should be used as an additional method together with thin-layer chromatography, for a more objective evaluation of the results of forensic chemical analysis of cadaveric material for phoxim.     

The determination of clozapine in blood and urine by gas chromatography-mass spectrometry]

A method for measuring closapine in the blood and urine by gas chromatography-mass spectrometry as a trifluoroacetic derivative is proposed. The threshold level for closapine detection is 25 ng/ml in the blood and 30 ng/ml in the urine. Calibration curves are linear in the range 0.025-5 mcg/ml for the blood and 0.03-50 mcg/ml for the urine. The method can be used in forensic chemical and clinical toxicological analysis.     

An initially unexplained death during prison sentence. Diagnostic verification by atomic absorption spectrometry

The authors report on the death of a 25-year-old man due to electric current in prison, which was not recognized at first. The fatal accident was caused by a self-made electric kettle. The only electrothermal skin lesions were some pinhead-sized electric marks on the left thumb. Careful external inspection of the body in combination with an analysis of the conductor material (aluminium) by means of atomic absorption spectrometry (AAS) revealed the cause of death and the source of accidental electrocution.