离子色谱-氢化物发生原子荧光法测定海水中4种不同形态的砷

建立了采用离子色谱-氢化物发生原子荧光联用技术(IC-HG-AFS)进行As(III)、As(V)、MMA、DMA 4种砷化合物形态分析的方法.对流动相、盐酸载流、还原剂、载气流速等条件进行了优化,并且考察了共存离子的影响.采用银柱有效去除海水中的Cl–,以减少海水基体的干扰.此方法能在12min内成功地分离As(III)、DMA、MMA和As(V),方法检出限分别为1.00、1.68、1.33和2.34μg/L,As(III)、MMA、DMA3种化合物线性范围在5~250μg/L之间,As(V)的线性范围在10~250μg/L之间,4种化合物的相对标准偏差在1.0%~8.8%之间,加标回收率为77.8%~96.3%.     

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.     

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。     

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.     

磁性离子交换树脂对水中双酚-A的吸附特性研究

研究了磁性离子交换(MIEX)树脂对双酚-A(BPA)的吸附过程,考察了初始浓度、温度、p H、共存离子和天然有机物等因素对吸附过程的影响,对试验结果进行了动力学和热力学分析。结果表明,MIEX树脂对BPA有很好的吸附效果,但是吸附量受BPA初始浓度的影响,随着初始浓度的增加,吸附量也增加;p H值小于8.0时,MIEX对BPA的吸附效果较好;共存阴离子的竞争吸附能力顺序为NO-3SO2-4HCO-3HPO2-4;腐殖酸的存在会减少BPA在MIEX树脂上的吸附量。该吸附过程更符合Langmuir模型,最大吸附容量为48.98 mg/g,温度越高最大吸附容量越低;伪二级动力学可以很好地描述BPA在MIEX树脂上的吸附;热力学分析说明MIEX树脂对BPA的吸附是自发进行的,吸附过程放热,因此升温不利于反应进行。     

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.     

原子荧光光谱测定水中锑的结果不确定度评定

采用直观的因果图,对原子荧光光谱法测定水中锑含量的结果不确定度来源及其对测量不确定度的影响进行了分析.建立了有效的数学模型,利用相对标准不确定度分步计算及整体合成进行测量不确定度的评定,并在锑含量为1.2μg/L的水样测定中,获得其相对标准不确定度为3.6%.     

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。     

The analytical separation of phosphate from natural water by ion exchange

An ion exchange method has been developed for separating inorganic orthophosphate from natural water samples. The technique makes it possible to determine orthophosphate by the molybdophosphate blue procedure without interference from phosphate esters or certain other forms of bound phosphorus. Experiments to examine the conditions under which phosphate is found in natural waters suggest that adsorption by high molecular weight organic substances such as lignins may account for a large fraction of the soluble phosphorus.     

Role of strong ion exchange resins in nitrosamine formation in water

N-Nitrosodimethylamine (NDMA) was formed when tap water was passed through a column containing only the anion exchange resin, thereby indicating that nitrosamine (NA) formation by the conventional acid catalyzed nitrosation reaction, as would be expected in the case of a mixed strong anion and cation resin system, was not the primary mechanism. The quaternary ammonium ion of the strong anion resin may be the amine precursor for NA formation. Strong anion and strong cation resins (Amberlite and Dowex brands^‡) were ineffective in concentrationg low levels of NDMA that were added to the influent. Accumulation of extremely low levels of NA already present in the water, therefore, also did not contribute importantly to the concentration of NA found in deionized water. In addition, the normal levels of cations and anions in water, and heavy metal ions were also not primarily responsible for this occurrence. There was, however, an unknown substance(s) in tap water that promoted NA formation. This unknown soluble substance(s) can be removed by activated carbon treatment or degassing techniques.     

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.     

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。     

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 zinc levels in waters from southeastern Spain by electrothermal atomic absorption spectrometry: relationship with industrial activity

An efficient method for the determination of nanogram levels of zinc in waters (potable, irrigation, waste and sea waters) is described. Acidified water samples were analyzed by an accurately optimized time/temperature program for electrothermal atomic absorption spectrometry. The samples were previously treated with a matrix modifier consisting of 0.1% Mg(NO3)2 in 0.5 M HNO3 and injected through a graphite tube with L'Vov platform. Sample recoveries, repeteability, and analyses of NIST reference material demonstrated the reliability and accuracy of this technique. Zinc concentrations ranged from 2.0 to 73.0 microg l(-1). No significant differences among the mean zinc levels determined in the four types of water considered from southeastern Spain were found. Zinc concentrations in waters from the zone were not affected by human and industrial activity.     

Determination of soluble aluminium concentration in alkaline humic water using atomic absorption spectrophotometry

The steps of the standard method to determine soluble aluminium concentration are filtering, followed by acidifying, then analysing with the atomic absorption spectrophotometer (AAS). When applied to alkaline humic water, acidification gives rise to the formation of humic acid as a brown particulate matter. Of the total soluble aluminium in the original water, 49-61% forms complexes with the particulate humic acid upon acidification. Although the AAS is capable of detecting the binding aluminium, the particulate nature of humic acid easily induces inaccurate readings as a result of the non-uniform distribution of the particulate matter. A more precise analysis of soluble aluminium concentration of alkaline humic water is shown to be achievable in basicified solutions instead. Basicified solutions keep humic acid in the soluble form; hence maintain the homogeneity of the sample.