Determination of Trace Amounts of Lead by Modified Graphite Furnace Atomic Absorption Spectrometry after Liquid Phase Microextraction with Pyrimidine-2-thiol

The liquid phase microextraction (LPME) was combined with the modified Graphite furnace atomic absorption spectrometry (GF-AAS) for determination of lead in the water and solid samples. In a preconcentration step, lead was extracted from a 2 ml of its aqueous sample in the pH = 5 as lead-Pyrimidine-2-thiol cationic complex into a 4 μl drop of 1,2 dichloroethane and ammonium tetraphenylborate as counter ion immersed in the solution. In the drop, the lead-Pyrimidine-2-thiol ammonium tetraphenylborate ion associated complex was formed. After extraction, the microdrop was retracted and directly transferred into a graphite tube modified by [W.Pd.Mg] (c). Some effective parameters on extraction and complex formation, such as type and volume of organic solvent, pH, concentration of chelating agent and counter ion, extraction time, stirring rate and effect of salt were optimized. Under the optimum conditions, the enrichment factor and recovery were 525% and 94%, respectively. The calibration graph was linear in the range of 0.01 - 12 μg?L–1 with correlation coefficient of 0.9975 under the optimum conditions of the recommended procedure. The detection limit based on the 3Sb criterion was 0.0072 μg?L–1 and relative standard deviation (RSD) for ten replicate measurement of 0.1 μg?L–1 and 0.4 μg?L–1 lead was 4.5% and 3.8% respectively. The characteristic concentration was 0.0065 μg?L–1 equivalent to a characteristic mass of 26 fg. The results for determination of lead in reference materials, spiked tap water and seawater demonstrated the accuracy, recovery and applicability of the presented method.

Determination of Copper and Lead Contents in Soil of the Yellow River Wetland in Shaanxi Province by Flame Atomic Absorption Spectrometry

[Objectives] The contents of copper and lead in the soil of the Yellow River Wetland were determined by flame atomic absorption spectrometry, which provides a theoretical basis for the treatment of soil pollution. [Methods] The soil was digested with a concentrated nitric acid-hydrofluoric acid-perchloric acid system, and the contents of heavy metals such as copper and lead in the Yellow River Wetland of Shaanxi Province were determined by flame atomic absorption spectrometry. [Results] The correlation coefficients reached 0.999 5 in the range of 0.00-1.00 mg/L, indicating good linearity. [Conclusions] The method is simple in operation, good in reproducibility, high in sensitivity to most elements, and can be widely used.

Measuring Conditions for the Determination of Lead in Iron-Matrix Samples Using Graphite Atomizers with/without a Platform in Graphite Furnace Atomic Absorption Spectrometry

In graphite furnace atomic absorption spectrometry (GF-AAS), the atomization process of lead occurring in graphite atomizers with/without a platform plate was investigated when palladium was added to an iron-matrix sample solution containing trace amounts of lead. Absorption profiles of a lead line were meas- ured at various compositions of iron and palladium. Variations in the gas temperature were also estimated with the progress of atomization, by using a two-line method under the assumption of a Boltzmann distribu- tion. Each addition of iron and palladium increased the lead absorbance in both the atomizers, indicating that iron or palladium became an effective matrix modifier for the determination of lead. Especially, palladium played a significant role for controlling chemical species of lead at the charring stage in the platform-type atomizer, to change several chemical species to a single species and eventually to yield a dominant peak of the lead absorbance at the atomizing stage. Furthermore, the addition of palladium delayed the peak after the gas atmosphere in the atomizer was heated to a higher temperature. These phenomena would be because the temperature of the platform at the charring stage was elevated more slowly compared to that of the furnace wall, and also because a thermally-stable compound, such as a palladium-lead solid solution, was produced by their metallurgical reaction during heating of the charring stage. A platform-type atomizer with palladium as the matrix modifier is recommended for the determination of lead in GF-AAS. The optimum condition for this was obtained in a coexistence of 1.0 × 10–2 g/dm3 palladium, when the charring at 973 K and then the atomizing at 3073 K were conducted.

Investigation of Distribution for Trace Lead and Cadmium in Chinese Herbal Medicines and Their Decoctions by Graphite Furnace Atomic Absorption Spectrometry

Lead and cadmium in herbal medicines are highly toxic to living organisms even in low concentrations. An effective method is developed for analysis of trace lead and cadmium in Chinese herbal medicines and their decoctions by graphite furnace atomic absorption spectrometry (GFAAS). The effects of analytical conditions on absorbance were investigated and optimized. A water-dissolving capability for Pb and Cd was investigated, and the contents of different species in five Chinese herbal medicines and their decoctions were analyzed. The content ratios (kow) of n-octanol-soluble Pb or Cd to water-soluble Pb or Cd were evaluated, and the distribution of Pb and Cd in water decoction at stomach and intestine acidities was developed, in the first time. The contents of water-soluble Pb and Cd, n-octanol-soluble Pb and Cd, and their content ratios were related with the kind of medicine and the acidity of the decoction. The proposed method has the advantages of simple operation, high sensitivity and high speed, with 3 σ detection limits of 4.2 pg for Pb and 0.1 pg for Cd.

Verification of Penetration of Lead in the Profile of Soil around the Former Battery Production Factory, Berat Albania

The current study reports the concentration of lead in top of the soil samples and its penetration until the depth of approximately 120 cm. Representative soil samples are collected around the former Factory Production of Batteries to Berat, Albania at a distance 80 - 900 m from factory. We have chosen 12 sampling points. We have collected a total of 55 samples where 31 were soil samples (12 top of soil and 19 were profile soil samples) and 24 were random vegetation samples. All soil samples were analyzed using Atomic Absorption Spectrometry for their lead content, at the Institute of Applied Nuclear Physics, University of Tirana, Albania. From results obtained the fraction of lead in profile soil samples was in range: 78 mg/kg - 52,982 mg/kg and average concentration of lead was 2976 mg/kg, while in random vegetation samples was in range: 0.238 - 5.573 mg/kg. In general, trend of the content of lead in profile soil samples was decreasing compared to the content of lead in the respective top soil samples. The concentrations of lead which have been found in analyzed soil samples are compared with the Maximum Contaminant Levels specified by the Directive 86/278/EEC. Also, we have calculated Hazardous Quoted for each sampling point which is found very high. HQ in representative surface soil samples is 0.4 - 80.7 times higher than normal.

国标火焰原子吸收法检测白酒铅含量范围的扩展研究

本实验建立了一种高含铅量白酒的检测方法,扩展了火焰法的适用范围,在一定程度上衔接了国标法中石墨炉法和火焰原子吸收光谱法检测范围之间的跨度。实验采用硝酸对试样进行消解,经过一系列萃取,通过火焰原子吸收分光光度计对高铅含量白酒进行了测定。结果表明:该方法线性良好,R2可达0.9996,方法检出限为0.58 mg/L;有较好的准确度和精密度,样品加标回收率为88.80%~104.40%,样品重复测定的相对标准偏差(RSD)在0.36%~0.80%。此外,对样品的取样体积进行了检验,结果表明,样品取样量为2 mL、10 mL、20 mL时,样品检测结果均符合准确度要求。

火焰原子吸收光谱法测定岩石样品中铜、铅、锌的研究

主要研究火焰原子吸收光谱法测定岩石样品中的铜、铅、锌。采用石墨消解仪和HF-HCl-HNO3-HClO4酸系消解样品的前处理方法效果相对较好,酸性介质可用盐酸或硝酸溶液,浓度宜为2%~5%。通过实验得出:铜、铅、锌的检出限分别为0.012μg/mL、0.057μg/mL、0.009μg/mL,测定下限分别为0.048μg/mL、0.228μg/mL、0.036μg/mL,方法RSD值(精密度)1.0%~3.6%,加标回收率97.29%~101.0%,符合岩石矿物分析规范的要求。火焰原子吸收光谱法测定铜、铅、锌具有操作简便、实验用时短、干扰少及较好的准确度和精密度的特点。

永泰县话梅中铅含量的检测分析

为调查研究永泰县话梅中铅含量情况,采购永泰县当地产话梅200份,采用石墨炉原子吸收光谱法对其铅含量进行检测分析。结果表明,永泰县话梅中铅的含量为0~1.10 mg·kg^(-1),平均含量为0.31 mg·kg^(-1),仅有1份话梅样品中铅含量超过0.8 mg·kg^(-1)的国家限量标准。200份话梅样本中铅检出率为85%,铅含量为0.41~0.80 mg·kg^(-1)的占17%,0.4 mg·kg^(-1)以下的占82.5%,整体合格率为99.5%,说明目前永泰县话梅质量安全较高,生产卫生较好。

金矿石中铅含量的测量不确定度评定

本研究依据GB/T 20899.5—2021方法1火焰原子吸收光谱法测定金矿石中的铅含量,建立数学模型,分析整个测定过程中不确定度的来源。样品的称量、定容体积、稀释及标准曲线的拟合等都会引入一定的不确定度分量。本文分别通过A类或B类评定方式对这些不确定度分量进行计算,并合成标准不确定度u,在置信概率为95%的情况下,取包含因子k=2,计算得扩展不确定度U=0.05%。计算发现,B类不确定度的贡献大于A类不确定度,而B类不确定度分量贡献最大的部分为标准曲线带来的不确定度,可以通过增加标准溶液数量以及试液的测量次数来降低标准曲线带来的不确定度影响。实验表明,在条件一致的情况下,试液测量次数由3次增加到5次,扩展不确定度可由0.05%降至0.04%。

基围虾中铅镉元素快速检测法的可行性分析

目的分析基围虾中铅元素、镉元素快速检测法的可行性。方法以基围虾作为研究对象,依据国标要求,筛选出5个符合规格的快速检测产品。通过5个快速检测产品对阴性样、1.0倍以及1.8倍限量值的阳性样中的重金属铅和镉进行快速测定,并通过石墨炉原子吸收光谱法对铅镉的快速检测结果进行验证。结果快检1和快检2在铅镉元素含量分别大于0.413 mg/kg及0.488 mg/kg时,检测结果显示为阳性;快检3和快检5在铅镉元素含量分别大于0.607mg/kg及0.604mg/kg时,检测结果显示为阳性,这说明海产品铅镉元素的快速检测产品对基围虾中铅镉元素快速测定具有一定的可行性,检测结果存在一定的差异,主要的原因可能为不同牌子的产品,在技术上存在一定的差异,导致产品的灵敏度存在差异。结论快速检测法测定基围虾中铅、镉元素具有可行性,这为海产品重金属元素测定提供了参考依据。

石墨炉原子吸收法测定地表水中铅的不确定度评定

对石墨炉原子吸收法测定地表水中铅从重复测定样品、工作曲线拟合、铅标准溶液及配制、样品前处理过程四方面进行不确定度分析,发现不确定度最大的部分来源于工作曲线拟合,之后是样品重复测定和样品前处理过程。在工作曲线拟合方面应适当缩小标准曲线范围,使工作曲线覆盖范围尽量与实际样品浓度相匹配,同时严格规范曲线配制的操作过程。在样品的重复测定方面,确保仪器运行的稳定是减小不确定度的关键。

石墨炉原子吸收光谱法检测蔬菜中铅元素实验条件的优化

目的:建立并优化检测蔬菜中铅元素的石墨炉原子吸收光谱法。方法:优化基体改进剂添加量、仪器灰化温度和原子化温度,并进行方法学验证实验。结果:最佳检测条件为选择5%硝酸钯溶液作为基体改进剂,使用量为5μL,灰化温度为800℃,原子化温度为1800℃。当铅含量在0~40.0μg·L^(-1)时,标准曲线方程为y=0.00479x+0.00487,相关系数R2=0.9997,说明线性关系良好,方法检出限为0.5μg·L^(-1),测定下限为0.01 mg·kg^(-1)。芹菜样品中3个水平的加标回收率为95.00%~98.33%,相对标准偏差为1.73%~8.67%。结论:本研究所建立的方法精密度和准确度较高,适用于蔬菜中铅含量的快速准确检测。

石墨炉原子吸收光谱法测定青梅中铅、镉含量

在云南省大理州洱源县不同梅子产地采集6份样品,采用石墨炉原子吸收光谱法测定青梅中铅、镉含量。结果表明,两种重金属元素在一定的浓度范围内线性关系良好,相关系数大于0.999 3;铅、镉检出限分别为1.83 μg·L^(-1)、0.027 μg·L^(-1),加标回收率在93.64%~95.87%。不同产地青梅中铅、镉含量的差别不大,铅含量大于镉含量,6份青梅样品的铅、镉含量均低于《食品安全国家标准 食品中污染物限量》(GB 2762—2017)中的限量值。

石墨炉原子吸收光谱法测定莱芜姜咸菜中铅的含量

通过优化实验程序,建立了微波消解-石墨炉原子吸收光谱测定姜咸菜中的铅含量的方法。结果表明,该方法的线性相关系数为0.9999,检出限为0.007 mg·kg^(-1),加标回收率为92.7%~100.6%,相对标准偏差为0.1%~1.3%。方法方便快捷,准确度好,精密度高,适用于姜咸菜中铅含量的测定。

铅试金加纯银富集-原子吸收光谱法测定铋渣中金含量

在铅试金方法中以加入适量纯银的方式富集金,从含有金的铋渣中提炼出金银合粒。合粒经稀硝酸溶解银后剩余金粒,分离后金粒经王水溶解定容,使用原子吸收光谱仪测定溶液中金量;同时用二次试金的结果进行补正,最终得到样品中金含量。讨论了样品中高含量铋对熔融、灰吹流程的影响,通过试验确定了试料的称样量及铅试金熔剂配料量;优化了二次试金的细节,提高了工作效率,并探讨了如何对一次试金的结果进行有效补正;通过加标回收的方式对分析方法的精密度和准确度进行了统计,该方法测定的金含量相对标准偏差为0.82%~1.69%;加标回收率为97.18%~102.84%。试验表明,本方法能快速准确地测定高铋物料中金的含量。

原子吸收光谱法测定粮油产品中铅、镉的含量

随着我国经济和技术的飞速发展,居民生活品质不断提升,人们对食品安全的关注也日益加深。然而,经济持续增长的同时也带来了一系列的环境问题,尤其是重金属污染问题,这对粮食安全构成了直接威胁。基于此,本研究针对原子吸收光谱法进行分析,并利用此种方法对粮油产品中的重金属含量进行测定,通过具体的研究和分析来解决食品安全问题。

原子吸收光谱法检测铅项目的应用分析

最新版《GB 2762—2022食品安全国家标准食品中污染物限量》对乳制品铅项目的限量指标加严了管控。为适配限量值标准,国家卫生健康委员会、国家市场监督管理总局重新修订发布了《GB5009.12—2023食品安全国家标准食品中铅的测定》方法,主要下调了液态食品的检出限及定量限。国家标准的变更对石墨炉原子吸收光谱法检测铅项目仪器条件及参数设置提出了更高要求。本研究通过对比分析石墨炉原子吸收分光光度计检测液态乳制品中铅项目时,升温程序各步骤不同温度及光斑通过石墨管不同位置对加标回收结果的影响,确定最佳升温程序条件,同时确定不同铅含量样品检测时元素灯光斑位置调节的方法及位置。

原子吸收光谱法测定铅的进展

对近年来国内原子吸收光谱法测定铅的进展进行了评述 ,内容包括火焰原子吸收光谱法、石墨炉原子吸收光谱法和氢化物发生原子吸收光谱法。

纳米二氧化钛分离富集石墨炉原子吸收光谱法测定水样中痕量铅

提出了纳米TiO2 分离富集 ,GFAAS测定水样中痕量铅的新方法。详细考察了纳米TiO2 对铅的吸附行为 ,结果表明 :在 pH 4 .0时 ,Pb2 + 可被纳米TiO2 定量富集 ,吸附于纳米TiO2 上的Pb2 + 可用 0 .1mol/L的硝酸完全解脱。本法对Pb2 + 的检出限为 5 2ng/L ,相对标准偏差为 4 .7% (n =10 ,C =0 .0 2mg/L)。本法已用于实际水样中铅的测定 ,结果满意。

微波消化-石墨炉原子吸收分光光度法测定进口西洋参中的铅

本文对进口西洋参中铅的测定方法进行了研究。本文利用微波消化比常规法更快、更安全、更环保、更准确的优点,对西洋参进行了前处理;利用石墨炉原子吸收分光光度法灵敏、高速、耗样量少等优点,对西洋参进行测定。本文设定了微波消化条件的程序,对微波消解的混合酸进行了选择,解决了最终的消化液其酸度对测定的影响问题,并对石墨炉原子吸收的测定条件进行了研究。依据多次实验结果,选择了合适的灰化温度和原子化温度,确定了最终的石墨炉升温程序。本方法铅的线性范围为0～100μg·L^(-1),检出限为2.80μg·L^(-1),相对标准偏差为0.91％,回收率为98.13％,方法的精密度及准确度均令人满意。