Determination of chromium in human milk, serum and urine by electrothermal atomic absorption spectrometry without preliminary ashing

In the present study a Perkin-Elmer 5000 atomic absorption spectrometer equipped with a tungsten--iodide lamp for improved background correction at the 357.9 nm chromium absorption line and an HGA 500 graphite furnace were employed for the direct determination of chromium in human serum, milk and urine. The method of standard additions was used: 0.25-0.75 ng Cr was added to 1 ml samples. Except for urine samples, a dilution of 1 + 1 to 1 + 2 with H2O was necessary in order to obtain correct calibration curves. The average concentration of chromium in all the samples of normal subjects was less than 0.5 ng Cr ml-1. The day-to-day variation for all of the pooled samples was around 10% (relative standard deviation). For urine, the accuracy of the method was tested by comparing the results of another laboratory for the same two round robin samples. Excellent agreement was found between the present method and those of the other laboratory that had used isotope dilution--mass spectrometry and continuum source wavelength modulated echelle--atomic absorption spectrometry to define the chromium concentration in the samples. The detection limit of the method, 0.05 ng Cr ml-1 for urine and serum and 0.1 ng Cr ml-1 for human milk, was sufficient for the biological fluids analyzed. The method was employed for the determination of chromium in 24-h urine samples of maturity onset diabetics supplemented with 20 or 200 micrograms Cr3+ d-1 for six weeks. It was shown that the 24-h urinary chromium excretion accurately indicates the daily dietary chromium intake of these patients.     

Cloud point extraction for speciation of chromium in water samples by electrothermal atomic absorption spectrometry

A new method based on the cloud point extraction (CPE) separation and electrothermal atomic absorption spectrometry (ETAAS) detection was proposed for the determination of chromium species. When the system temperature is higher than the cloud point extraction temperature (CPT) of selected surfactant p-octyl polyethyleneglycolphenyether (Triton X-100), the complex of Cr(VI) with dibromophenylfluorone (Br-PF) could enter surfactant-rich phase, whereas the Cr(III) remained in aqueous phase. Thus, an in situ separation of Cr(VI) and Cr(III) could be realized. Cr(VI) in surfactant-rich phase was analyzed by ETAAS and Cr(III) was calculated by subtracting of Cr(VI) from the total chromium which was directly determined by ETAAS. The main factors affecting the cloud point extraction, such as pH, concentration of Br-PF and Triton X-100, equilibration temperature and time, were investigated systematically. Under the optimized conditions, the quantitation limit for Cr(VI) as low as 0.01 microg/L was obtained by preconcentrating a 10 mL sample solution, and the relative standard deviation (n=6, c=2.0 microg/L) was 2.6%. The proposed method was applied to the speciation of chromium in different water samples and the recoveries in the range of 98.9-105.3% were obtained by spiking the real samples. In order to verify the accuracy of the method, a certified reference water sample was analyzed and the results obtained were in good agreement with the certified values.     

火焰原子吸收光谱法测定玻璃中钾、钠含量

建立了一种火焰原子吸收光谱法（FASS）测定玻璃中的钾、钠含量的方法,对火焰原子吸收的狭缝宽度、燃烧头角度和元素的测定波长进行了优化。结果表明,该方法测定钾含量的相对标准偏差（RSD）为3.4%~4.8%,加标回收率为95%~102%;测定钠含量的相对标准偏差（RSD）为0.8%~4.8%,加标回收率为92%~105%。     

Determination of toxic elements in biological materials by furnace atomic absorption spectrometry

Graphite furnace AAS has evolved into its third phase of maturity. Initially it was considered to be the ultimate high sensitivity interference-free technique for trace metal analysis. This phase quickly ended following the examination of complex sample types. We believe that the introduction of high-performance background correction such as Smith-Hieftje, delayed atomization techniques, and aerosol deposition have taken graphite furnace AAS into its third phase. The technique can now be used more routinely and more easily for the analysis of complex materials such as biological fluids.     

石墨炉原子吸收法测定岩石中的铅

介绍了用吡咯啶二硫代氨基甲酸铵(APDC)、二乙基二硫代氨基甲酸钠(DDTC)、甲基异丁基甲酮(MIBK)体系萃取,石墨炉原子吸收法测定样品中的铅的实验方法,分析了实验的结果,指出此方法准确可靠,样品测定证明可以满足岩石样品分析的要求。     

Determination of cadmium in whole blood and scalp hair samples of Pakistani male lung cancer patients by electrothermal atomic absorption spectrometer

A large number of epidemiologic studies have been undertaken to identify potential risk factors for cancer, amongst which the association with cadmium has received considerable attention. There is compelling evidence in support of positive associations between cadmium and risk of lung cancer. In present study we measured the concentration of Cd in whole blood and scalp hair samples of 120 male lung cancer patients (smokers) and 150 controls or referents (smokers and nonsmokers) from different cities of Pakistan. Both referents and patients were of same age group (ranged 40-70 years), socio-economic status, localities and dietary habits. The scalp hair and whole blood samples were oxidized by 65% nitric acid: 30% hydrogen peroxide (2:1) ratio in microwave oven. To check the validity of the proposed method, a conventional wet acid digestion method was used to obtain total Cd concentration in certified samples of human hair BCR 397 and Clincheck control-lyophilized human whole blood. All digests were analyzed for Cd concentration by electrothermal atomic absorption spectrometer (ETAAS). The results of this study showed that the average Cd concentration was higher in the blood and scalp hair of lung cancer patients at different stages as compared to controls (p<001). The smoker referents have high level of Cd in both biological samples as compared to nonsmoker subjects. These results illustrate that the patients who continued smoking after confirmed diagnosis of lung cancer have 34.2-67.26 and 22.4-57.3% more Cd in blood samples and scalp hair than lung cancer patients who cease smoking. This study is compelling evidence in support of positive associations between cadmium, cigarette smoking and lung cancer risk.     

Determination of trace concentrations of lead and nickel in human milk by electrothermal atomisation atomic absorption spectrophotometry and inductively-coupled plasma emission spectroscopy

The lead and nickel content of 179 human milk samples has been determined by atomic absorption spectroscopy (lead) and inductively-coupled plasma emission spectropscopy (nickel). The samples originated from different countries and different sociological groups in widely varying areas of the world.     

Lead and cadmium in human teeth from Jordan by atomic absorption spectrometry: Some factors influencing their concentrations

The aim of this study was to measure the concentrations of lead (Pb) and cadmium (Cd) in human teeth and to investigate the affecting factors. Teeth samples (n = 268) were collected from people living in different cities in Jordan including Amman, Zarqa, Al-Mafraq and Irbid and analyzed for Pb and Cd using atomic absorption spectrometry (AAS). A questionnaire was used to gather information on each person, such as age, sex, place where the patient lives, smoking, presence of amalgam fillings inside the mouth, and whether the patient uses toothpaste or not. The mean concentrations of Pb and Cd were 28.91 microg/g and 0.44 microg/g, respectively. The results indicate that there is a clear relation between Pb and Cd concentrations and the presence of amalgam fillings, smoking, and place of living. Pb was sex-dependent, whereas Cd was not. Our results show that Pb and Cd concentrations in samples obtained from Al-Mafraq and Irbid are higher than those obtained from Amman and Zarqa. Pb was highest in Mafraq, whereas Cd was highest in Irbid. The Pb and Cd concentrations in teeth from smokers (means: Pb = 31.89 microg/g, Cd = 0.49 microg/g) were significantly higher than those from nonsmokers (means: Pb = 24.07 microg/g, Cd = 0.37 microg/g). Pb and Cd concentrations in teeth of patients with amalgam fillings (means: Pb = 31.02 microg/g and Cd = 0.52 microg/g) were significantly higher than those from patients without amalgam fillings (means: Pb = 26.87 microg/g and Cd = 0.41 microg/g). Our results show that brushing the teeth daily with toothpaste does not significantly decrease the concentration of both Pb and Cd. The mean concentrations of Pb and Cd do not vary significantly between the ages 20-30, 31-40, and 41-50, but both increased rapidly at age 51-60.     

Determination of metals in fish livers by flameless atomic absorption spectroscopy

The samples are digested in nitric acid and evaporated to near dryness. Hydrogen peroxide is then added for complete oxidation of fat residues. Determination of metals is performed by flameless AAS with graphite furnace and results evaluated by the method of standard addition. The method is suitable for the determination of some non-volatile metals in fish livers in which the amount of available sample is limited; Pb, Cd, Cu and Zn have been determined in such samples.     

原子荧光法测定饮用水中痕量铅

采用原子荧光法测定生活饮用水中铅的含量。试验结果表明，该方法的回归方程为y=37．00x＋28．25，r=0．999，在0．001～0．025mg／L范围内有良好的线性关系。采用该方法测定水中痕量铅能获得理想的结果，可在生活饮用水检测中推广运用。     

氢化物原子荧光法测定聚合氯化铝中汞的含量

探讨了应用原子荧光光度计测定聚合氯化铝中汞含量的技术和方法,测定方法以10%盐酸为介质,15g/L硼氢化钠为还原剂。实验得到,该方法线性范围为0～10.0μg/L,相关系数r=0.9996,检出限为0.054μg/L,相对标准偏差为1.78%,回收率为94.6%～103.7%。实验结果表明,该方法精密度好,回收率高,操作简单,可用于测定聚合氯化铝中汞的含量。     

Determination of lead in blood by graphite furnace atomic absorption spectrometry--a critique

Graphite furnace atomic absorption spectrometry (GFAAS) is increasingly becoming the method of choice for the determination of Pb in blood. The major GFAAS methods that have been published to date include: (i) direct introduction of the sample into the furnace; (ii) dilution with water, Triton X-100 or acid; (iii) deproteinization with nitric acid; (iv) matrix modification; and (v) solvent extraction. This review focuses on the difficulties associated with each of these methods, and highlights recent attempts to overcome matrix interferences and improve the accuracy and precision of Pb determination in blood using modern furnace technology, especially the stabilized temperature platform furnace.     

Precision and accuracy control in the determination of heavy metals by atomic absorption spectrometry

Many metals can be determined by direct aspiration of samples into an air‐acetylene flame in Atomic Absorption Spectrometry (AAS). The precision and accuracy of environmental samples analysed by AAS technique depends on the different factors. The capability of AAS can be well defined by considering its performance characteristic, detection limit, accuracy and precision. The analytical performance of AAS can be evaluated by drawing quality control charts, which defines whether the analysis can continue or stop. The paper discusses the evaluation characteristic of AAS used for detection of low level concentration and its trend for detection.     

Determination of nitrite ion in waste and treated waters by resonance Raman spectrometry

The determination of NO₂⁻ ion in aqueous solutions by resonance Raman spectrometry has been examined in view of the application of the method to an optimum control of waste water treatment. In order to induce the resonance Raman effect, NO₂⁻ has been transformed into a colored product (azo dye) by a chemical reaction. From the resonance Raman spectra of the resultant colored product, it has been clarified that the detection limit of NO₂⁻ by this method is about 0.5 ppb, an order of magnitude lower than that of usual colorimetry, and that the analytical curve can be fitted well enough to a straight line in the concentration range below 140 ppb. The sensitivity of this method is regulated by the background intensities of sample solutions, and it has been shown that in the present case, the addition of sodium thiocyanate brings about a marked decrease of background intensities. Moreover, it has been proved that the application of the method developed here to practical waste and treated water samples produces appropriate results. Finally, the excellent selectivity of this method has been demonstrated, and the process of simultaneous determination of NO₂⁻ and NO₃⁻ has been proposed.     

石墨炉原子吸收法测定纸杯微量溶出铅的研究

采用石墨炉原子吸收法测定纸杯中微量溶出铅含量,通过对干燥、灰化、原子化、除残阶段的研究,确定了铅的最佳测定条件,在此条件下,测定了铅的检出限、精密度和回收率,达到了满意的结果。     

Determination of nitrate ion in waste and treated waters by laser raman spectrometry

The determination of NO₃⁻ ion in pure and natural waters by laser Raman spectrometry has been examined. It is shown that in the case of pure water samples, the detection limit of NO₃⁻ is about 2 ppm, and that the analytical curve in 6–100 ppm can be fitted well enough to a straight line. In the case of waste and treated waters, the detection limit becomes about an order of magnitude higher than that in the case of pure water because of the strong luminescence of water samples. In this study, the reduction of this background has been pursued by various methods, and it is demonstrated that the addition of potassium iodide as a quencher makes the background markedly smaller. By this procedure, the sensitivity becomes comparable to that in the case of pure water samples. It is proved that under such circumstances, laser Raman spectrometry can be applied satisfactorily enough to the analysis of NO₃⁻ in actual waste and treated waters.     

Speciation of selenium in plant water extracts by ion exchange chromatography-hydride generation atomic absorption spectrometry

Determination of selenium (Se) speciation in plants is important in studying the bioavailability and toxicity of Se in Se-contaminated soil/sediment. In this study, we used an anion exchange resin (Dowex 1-10X) to separate Se into non-amino acid organic Se, Se-amino acids, selenite (Se [IV]) and selenate (Se [VI]) in a plant (Stanleya pinnata) extract. The hydride generation atomic absorption spectrometry (HGAAS) was used to determine concentrations of these Se compounds in plant extracts. Results showed that Se compounds can be quantitatively separated by the resin column. Recovery of five spiked standard Se compounds (trimethylselenonium ion (TMSe+), dimethylselenoxide (DMSeO), selenomethionine (Semet), Se [IV] and Se [VII]) in the plant extract ranged from 92.9 to 103%. Water extractable Se accounted for 60.4-72.6% of the total Se in the plant. Among the soluble Se compounds in the plant extract, Se-amino acids were 73-85.5%, Se [VI] ranged from 7.5 to 19.5% and non-amino acid organic Se was less than 7%. Se [IV] in most samples was below the detection limit (1 microg/g). This study showed that considerable amounts of the accumulated Se [VI] in the plant was metabolized to Se-amino acids during growth of the plant.     

Electrochemical preconcentration combined with atomic absorption spectrometry for the determination of heavy metals in water samples

The coupling of electrochemical preconcentration with atomic absorption spectrometry as a means of suppressing matrix effects is reviewed. Merits, limitations and future trends are outlined and discussed.