嵌段分子筛聚合材料P123-SH萃取分离-石墨炉原子吸收光谱法分析痕量铬的形态

研究了嵌段分子筛聚合材料P123-SH萃取分离-石墨炉原子吸收光谱法对尿中痕量铬的形态分析方法,探讨了嵌段分子筛聚合材料P123-SH吸附铬的原理和最佳条件。在pH 7.0、常温下,Cr3+和Cr(Ⅵ)被很好的分离,且Cr3+可被该材料定量吸附,其吸附容量为6.15 mg/g。吸附的Cr3+可用2 mol/L的HCl洗脱,用石墨炉原子吸收法测定洗脱下来的Cr3+,往溶液中加入0.1%抗坏血酸将Cr(Ⅵ)还原为Cr3+测总铬,Cr(Ⅵ)含量为总铬减去Cr3+,方法测定Cr3+的检出限为0.011μg/L(3σ,n=11),线性范围为0.1～10μg/L,加标回收率在94%～106%之间,对0.50μg/L的Cr3+溶液平行测定7次,RSD为3.6%。方法可应用于生物样品和环境样品中痕量铬的形态分析。     

微波消解石墨炉原子吸收法测定环境空气中痕量锡

建立石墨炉原子吸收法测定环境空气中痕量锡的方法。采用混合纤维素微孔滤膜采集环境空气样品,用硝酸–氢氟酸微波消解样品,以5%硝酸镧–10%酒石酸混合液作基体改进剂,石墨炉原子吸收法进行测定。当采样体积为4 800 L,定容体积50 m L时,方法检出限为0.024μg/m~3,样品加标回收率为96.0%~106.0%,测定结果的相对标准偏差为2.74%~5.81%(n=7)。该方法样品处理操作过程简单,酸用量少,可用于环境空气中痕量锡的测定。     

汞的电热原子吸收研究及其应用

利用Se作基体改进剂，详细研究了汞的石墨炉原子吸收测定条件，并将方法成功地用于人发中痕量汞的测定。     

二苯硫脲-醋酸丁酯萃取-石墨炉原子吸收法测定地球化学样品中痕量银

对石墨炉原子吸收光谱法测定地球化学样品中痕量银进行了研究。样品经盐酸、硝酸、硫酸、高氯酸溶解,在盐酸(1.2mol/L)介质中用醋酸丁酯萃取银与二苯硫脲螯合物,用石墨炉原子吸收光谱法测定地球化学样品中痕量银,方法检出限为0.011ng/mL,相对标准偏差(RSD,n=11)为6.0%~12.2%,加标回收率为96.00%~105.00%。能满足地球化学样品中银含量为0.02~5μg/g范围内银测定的准确度和精密度的要求。     

石墨炉原子吸收光谱法测定生活饮用水中砷的方法优化

建立了石墨炉原子吸收光谱(GFAAS)法测定生活饮用水中砷的方法。升压放电空心阴极灯的使用,降低了基线噪声水平和检出限。对温度程序、化学基体改进剂和热稳定剂进行了优化并用于GFAAS测定砷,无需进行初步处理。研究结果显示,线性方程为y=0.005 62x+0.000 04,相关系数R为0.998 3,样品体积为16μL时的检出限为0.26μg/L。加标回收率为98.1%～99.2%,相对标准偏差5%。取实际饮用水样验证了其适用性。     

Application of Solid Sampling for the Determination of Total Fluorine in Fish and Seafood by High-Resolution Continuum Source Graphite Furnace Molecular Absorption Spectrometry

Total fluorine concentrations in some fish species and seafood such as mussels, squid (calamary), and shrimp were determined using the molecular absorption of calcium monofluoride (CaF) generated in a graphite furnace using a high-resolution continuum source atomic absorption spectrometer and direct solid sampling. The fish fillets and seafood were dried at 110°C, minced finely, put on the platform using masses less than 1.2?mg, and introduced to the graphite furnace with 20?µg of calcium by a solid sampling accessory. The effects of CaF wavelength, graphite furnace program, amount of sample introduced to the furnace, the use of modifier on the determination of fluorine were investigated and optimized. The absolute limit of detection and characteristic mass of the method were 0.28 and 0.14?ng of fluorine, respectively. By applying the optimized parameters, the concentrations of fluorine in various fish species and seafood were determined.     

石墨炉原子吸收光谱法测定生活饮用水中砷的方法优化

建立了石墨炉原子吸收光谱(GFAAS)法测定生活饮用水中砷的方法。升压放电空心阴极灯的使用,降低了基线噪声水平和检出限。对温度程序、化学基体改进剂和热稳定剂进行了优化并用于GFAAS测定砷,无需进行初步处理。研究结果显示,线性方程为y=0.005 62x+0.000 04,相关系数R为0.998 3,样品体积为16μL时的检出限为0.26μg/L。加标回收率为98.1%～99.2%,相对标准偏差<5%。取实际饮用水样验证了其适用性。     

微波消解-石墨炉原子吸收光谱法测定纸质包装材料中铅含量

建立了微波消解-石墨炉原子吸收光谱法测定纸质包装材料中铅含量的方法.该方法具有良好线性关系,线性相关系数R~2为0.999 5,检出限为0.028μg/L,回收率为97%~102%,其相对标准偏差在3.14%~5.76%之间,优点为检出限低、精密度好、准确度高,能精确测定纸质包装材料中的铅含量.     

石墨炉原子吸收法测定生物样品中的铊

为建立测定生物样品中铊的石墨炉原子吸收法,通过微波消解,采用基本改进剂,改变石墨炉灰化温度等操作条件,提高了该法的准确度和精密度.结果表明,方法的线性范围为0～100 μg/L;检出限:血为0.10 mg/L;尿为0.02 mg/L;头发为0.20 mg/kg;回收率:血为83.1%～108%;尿为89.6%～105%...     

石墨炉原子吸收光谱法间接测定蒸汽含水率

利用石墨炉子吸收光谱法测定蒸汽发生器循环水和蒸汽冷凝水中的铯则间接测定蒸汽含水率。蒸汽含水率等于冷凝水中铯的浓度除以循环水中铯的浓度。石墨炉原子吸收光谱可以准确测定０．１ｇ／Ｌ至１ｍｇ／Ｌ浓度的铯,样品中可能存在的一些物质对测定没有干扰。本方法可以满足测定蒸汽含水率的要求,实现了数百份含水率样品的测试。     

Usage of Artificial Neural Network (Back Propagation) in Optimising Salicylic Acid Determination with Ferric(III) Nitrate

Abstract

The use of artificial neural networks (ANN) in optimizing salicylic acid (SA) determination is presented in this paper. A simple and rapid spectrophotometric method for salicylic acid (SA) determination was carried out based on the complexation of salicylic acid–ferric(III) nitrate, SAFe(III). The SA forms a stable purple complex with ferric(III) nitrate at pH 2.45. The useful dynamic linear range is 0.01–0.35 g/L. It has a maximum absorption at 524 nm and the stability is more than 50 hours. The results were used for artificial neural networks (ANNs) training to optimize data. For training and validation purposes, a back‐propagation (BP) artificial neural network (ANN) was used. The results showed that ANN technique was very effective and useful in broadening the limited dynamic linear response range mentioned to an extensive calibration response (0.01–0.70 g/L). It was found that a network with 22 hidden neurons was highly accurate in predicting the determination of SA. This network scores a summation of squared error (SSE) skill and low average predicted error of 0.0078 and 0.00427 g/L, respectively.     

双孔石墨管原子吸收法测定化探样品中的痕量金

建立了双孔石墨管原子吸收法测定化探样品中痕量金的方法。以王水溶解样品,泡沫塑料吸附,10 g/L的硫脲溶液解脱,2%抗坏血酸作为基体改进剂,用双孔石墨管原子吸收法测定化探样品中的痕量金。该方法仪器分析时间由65 s缩短到32 s,提高了工作效率,方法标准曲线线性相关系数为0.999 8,检出限为0.045 ng/g,测定结果的相对标准偏差为4.1%~6.9%(n=7),标准样品测定值与推荐值的相对偏差小于3.24%。该法适合批量化探样品中金的测定。     

Determination of Vanadium in Tissues By Atomic Absorption Spectrophotometry

Abstract

A simple and sensitive method for the determination of vanadium in tissues was established by using atomic absorption spectrophotometry with graphite furnace atomisation. The proposed method includes formation of a chelate-complex by reacting vanadium with pyrrolidine dithiocarbamate (PDCA), extracting the chelate with xylene and measurement of the extract using atomic absorption spectrometry. The recoveries of added vanadium in various rat tissues were 96.7 and 109.3%, within 8.6% of the coefficient variation. The sensitivity of this method is 10 – 50 times higher than previous methods, the detection limit is 0.01 μg/g.     

Sensitive detection of ionic organolead compounds by coupling hydride generation (HG) with transversely heated graphite atomizer-atomic absorption spectrometry (THGA-AAS)

The detection of ionic alkyllead compounds using the coupling of flow injection analysis system-hydride generation (FIAS-HG) with transversely heated graphite atomizer atomic absorption spectrometry (THGA-AAS) has been worked out. Very low limits of detection can be achieved if the hydride products are enriched in the graphite furnace. Under optimised conditions (concentration of sodium borohydride, hydrogen peroxide and acidity as well as the furnace temperature) calibrations are carried out in the range of 0.1 to 5 μg/L. With a 1.5 mL sample loop, the limit of detection is calculated to be about 7 ng/L, but it can be lowered to below 1 ng/L if larger sample volumes are used for the enrichment.     

润滑油中痕量铜的石墨炉原子吸收光谱法测定

润滑油、Tween80、1%硝酸溶液三种组分按1.5∶3∶21的体积比可形成稳定的微乳液.采用标准加入法,微乳液直接进样,石墨炉原子吸收光谱法测定润滑油中铜.进样量为20μL,对最佳原子化条件进行了试验.方法的精密度为5.1%,检出限为0.055mg.L-1,回收率为96.7%～105.0%.     

国标测定土壤中铅测定方法改进的探讨

为改进测定土壤中铅的石墨炉原子吸收法,通过湿法消解,应用基体改进剂磷酸二氢铵,提高方法的准确度和精密度.结果表明,方法的线性范围为0.0 ～ 50.0 μg/L,检出限为0.21mg/kg,回收率为82.6％～94.4％,该方法具有干扰因素少,灵敏度高、准确的特点,可推广应用.     

石墨炉原子吸收分光光度法测定水中钛

建立石墨炉原子吸收分光光度法测定水中痕量可溶性钛和总钛。测量可溶性钛的样品通过0.45μm水系微孔滤膜过滤后直接测定,测量总钛的样品根据不同类型采用硝酸、过氧化氢、硫酸的不同组合进行消解。通过试验确定了最佳石墨炉程序升温工作条件和热解涂层石墨管的应用。干扰试验表明水中常见共存离子不干扰钛的测定。本方法经6家实验室验证,在0~250μg/L范围内线性良好,方法检出限可溶性钛为4.0μg/L,总钛为7.0μg/L。测定结果的相对标准偏差不大于12%(n=6),加标回收率为90.0%~107%,该方法对钛标准物质测定结果的相对误差为–3.4%~2.4%。该方法准确、可靠,检出限低,干扰少,易于推广应用。     

硫脲型树脂富集—石墨炉原子吸收光谱测定地质水中痕量金

本文研究了硫脲型树脂对金的吸附条件，提出了以水文地球化学探矿为目的现场富集，石墨炉原子吸收光谱测定地质水中痕量金的方法，实验表明：该树脂在［Ｈ＾＋］＞０．２ｍｏｌ／Ｌ的较宽酸度范围内，在最大流速情况下对天然水中痕量金进行富集，测得回收率达９８％以上，大部分共存离子不影响金的富集与测定，方法的检出限为０．０５ｎｇ／Ｌ。     

灰铸铁石墨形态的自动分类

在所提取的纹理特征的基础上,使用误差后向传播神经网络构建了一种优化的人工神经网络人顺。实现了灰铸铁石墨态的自动分类。用于描述石墨形态特征由分形维,粗细参数和二维自回归系数共同组成。该法成功地将人工神经网络引入了对灰铸铁石墨形态的分类,相对于传统人工目测法是一种很大的进步,而神经网络分类器的优化方法对其它神经网络模型的构也具有一定参考价值。     

Determination of manganese, iron and copper in sodium by chemical modification/graphite furnace atomic absorption spectrometry

Trace Mn, Fe and Cu in sodium were determined by chemical modification/graphite furnace atomic absorption spectrometry. The sodium sample was changed into NaOH in a desiccator by room temperature water vapor generated under reduced pressure, then the NaOH was dissolved in water and HNO(3) was added to give a clear solution. The solution was analysed by chemical modification/graphite furnace atomic absorption spectrometry. A nickel nitrate modifier was effective in improving integrated absorbance signals and the reproducibility of measurement. Analytical results for Mn, Fe and Cu were 170, 970 and 210 ng/g and relative standard deviations (n = 5) were 3.5, 5.8 and 6.7%, respectively. These results agreed with the values obtained from a chelating resin preconcentration/ICP-AES method.