石墨炉原子吸收法测定调味品中痕量铅

采用石墨炉原子吸收光谱法测定不同调味品中铅含量的分析方法.样品采用干法灰化处理,灰化温度为500℃,灰化时间为6h,残渣用1.0％硝酸溶解,然后加入硝酸铵做基体改进剂,优化了仪器条件后进样分析.铅浓度在0μg/L～50μg/L范围内呈良好线性关系,方法最低检出限在0.6μ g/L,回收率为83.80％～87.65％,相对标准偏差RSD为1.82％～3.40％.该方法是一种快速,灵敏,准确的分析方法,可用于调味品中铅的测定.     

悬浮液进样石墨炉原子吸收光谱法测定乳粉中 痕量铬

目的建立了乳粉加水和曲拉通溶解,利用石墨炉原子吸收光谱法直接测定铬的检测方法。方法采用NH4H2PO4作基体改进剂,降低原子化温度,解决拖尾现象;在石墨炉升温过程中采用分步干燥和分步灰化优化升温程序,降低灰化损失。结果铬浓度在0~30μg/L范围内具有良好的线性关系,相关系数为0.9995;方法检出限为4μg/kg;利用该法测定乳粉考核样品中铬的含量,回收率为98.9%,相对标准偏差(n=6)为3.0%;利用本法对10批奶粉进行测定,结果均低于0.1mg/kg,与国标方法无显著差异。结论该法简便快速、灵敏度高、污染少,适用于乳粉以及液体乳中痕量铬的快速准确测定。     

Characterization of trace metals in vegetables by graphite furnace atomic absorption spectrometry after closed vessel microwave digestion

A simple and expeditious method for the determination of trace metals (cadmium, chromium, copper, manganese and lead) is proposed. The metals are extracted from their matrix by using nitric acid and hydrogen peroxide in a closed-vessel microwave digestion system for their subsequent detection by graphite furnace atomic absorption spectrometry (GFAAS). The sample preparation procedure facilitates the overall analytical process and enables the construction of calibration curves from inorganic standards. The ensuing method provides good linearity and sensitivity for the five metals, with limits of detection and quantization spanning the ranges 0.05–2.20 and 0.15–7.34 μg/kg, respectively. This sensitivity level is quite appropriate for the intended application. Accuracy was assessed by using a certified reference material (NCS ZC85006 Tomato), for which the proposed method provided amounts of metals consistent with their certified values. The proposed method was applied to tomato, pepper and onion, which are widely consumed in Mediterranean countries.     

石墨炉原子吸收法测定草莓中铅的方法优化

目的建立石墨炉原子吸收法检测草莓中铅含量的方法,实现对草莓中铅含量准确检测。方法分别对不加基体改进剂的方法和加入基体改进剂的3种方法的检出限和相关性进行初步筛选;主要对石墨管升温程序进行优化,并通过加标回收实验来确认最佳方法。结果在最佳方法下检测草莓中铅含量,在0～100 ng/mL浓度范围内线性关系良好,相关系数为0.99625,检出限为9.5μg/kg;平均加标回收率为89.0%～94.4%,变异系数为4.42%～14.61%。结论优化的方法相关性好,检出限低,精密度好,可实现对草莓中铅的准确检测。     

浊点萃取-石墨炉原子吸收光谱法测定铬的形态

采用浊点萃取-石墨炉原子吸收光谱法(CPE-GFAAS)测定铬的形态。方法 以GFAAS为检测手段,TritonX-100为表面活性剂,8-羟基喹啉(8-HQ)为络合剂,考察pH和Triton X-100的用量、温度和时间等对浊点萃取Cr(Ⅲ)的影响。通过测定总铬和Cr(Ⅲ),计算出Cr(Ⅵ)的含量。结果 最佳浊点萃取条件为pH=9,1.0ml 3% Triton X-100,水浴95℃,20min。方法检出限为0.2μg/L,精密度RSD为4.1%,加标回收率在88%～98%之间。结论 本方法污染小、简便快速、准确灵敏、精密度好。     

石墨炉原子吸收法测定稻谷中铅含量前处理方法比较

研究采用石墨炉原子吸收法测定稻谷中铅含量的几种不同前处理方法,分别采用压力消解罐消解、微波消解、干法灰化和湿法消解四种前处理方法提取同一稻谷样品中的铅.用石墨炉原子吸收法测定,以磷酸二氢铵和硝酸镁混合溶液作为基体改进剂,铅标准溶液浓度范围为5、10、20、40、50 ng/mL,相关系数=0.999 9.压力消解罐消解、微波消解、干法灰化和湿法消解四种前处理方法测定结果的回收率分别为97.6％、82.3％、82.9％和87.1％.结果表明,四种前处理方法各有优缺点,均可用于稻谷中铅含量的测定.     

石墨炉-原子吸收光谱法测定大米中镉的不确定度评定

目的评定石墨炉-原子吸收光谱法(graphite furnace atomic absorption spectrometry, GFAAS)测定大米中镉含量的测量不确定度。方法依据CNAS-GL06《化学分析中不确定度的评估指南》、JJF 1059.1-2012《测量不确定度评定与表示》规定的基本程序,通过建立数学模型,分析确定不确定度来源,计算得到测量结果的合成标准不确定度和扩展不确定度。结果以石墨炉-原子吸收法测定大米中镉含量,其不确定度主要来源为标准曲线拟合,其次为测量重复性,Cd含量为(0.19±0.01)mg/kg,k=2。结论本方法客观可靠,可以分析GFAAS检测大米中镉的不确定来源和其影响程度,为降低不确定度,提高检测准确度有重要意义。     

石墨炉原子吸收分光光度法测定自制阳性猪肉中铅的不确定度评定

目的评估用石墨炉原子吸收分光光度法测定自制阳性猪肉中铅的不确定度,以找出影响不确定度的因素,为评价检验结果提供科学依据。方法建立猪肉中铅含量不确定度的数学模型,分析不确定度来源,并进行不确定度的评定。结果自制阳性猪肉中铅的含量为0.236 mg/kg,扩展不确定度为0.026 mg/kg(包含因子k=2),影响不确定度的主要因素是标准曲线线性拟合和分析仪器。结论可通过控制标准曲线校准过程和加强对分析仪器的保养维护,来降低石墨炉原子吸收分光光度法测定猪肉中铅含量的不确定度。     

溶剂稀释植物油直接进样石墨炉原子吸收测定铅含量

建立了溶剂稀释植物油直接进样石墨炉原子吸收测定铅含量的方法。以磷酸二氢铵和硝酸镁混合溶液为基体改进剂,正丁醇溶解植物油,形成均匀透明的溶液,利用石墨炉原子吸收光谱仪测定植物油中的铅含量。优化了石墨炉原子吸收光谱法测定参数。结果表明:在优化条件下,该方法在铅质量浓度0~80μg/L范围内具有良好的线性关系(r=0.996),精密度实验RSD为3.4%~5.8%,检出限为3.2μg/L,回收率为96.0%~104.0%,RSD为3.6%~4.2%。该方法简单快速,灵敏度高,回收率好,适用于植物油中的铅含量测定。     

Evaluation of W-Rh permanent modifier for lead determination in sugar by graphite furnace atomic absorption spectrometry

An alternative procedure that improves the performance of graphite atomizers for the determination of Pb in sugar by electrothermal atomic absorption spectrometry is described. The procedure is based on the injection of 10 μl of an acidified aqueous solution containing 8% w/v sugar and 0.2% v/v HNO₃ into integrated graphite platforms. Either transversely (THGA) as well as longitudinally heated graphite atomizers (LHGA) were evaluated by using conventional co-injection of 0.03% Pd + 0.05% Mg(NO₃)₂ or thermally treated platforms with 250 μg W + 200 μg Rh and co-injection of 5 μg l⁻¹ Rh solution. With W-Rh under the same analytical conditions, the lifetimes of THGA and LHGA reached up to 1110 and 900 firings, respectively. With Pd + Mg the LHGA tube lifetime was limited to approximately 500 firings, but for THGA up to 1020 firings were made with a single tube. Characteristic masses were 11 and 29 pg Pb for LHGA and THGA, respectively. Detection limits (3 s) based on sugar blank solution and on integrated absorbance were 5.0 mg kg⁻¹ with LHGA and 9.3 mg kg⁻¹ Pb for THGA. In general, the coefficients of variation of 20 consecutive measurements of a solution containing 50 μg l⁻¹ Pb were lower than 5%. The obtained detection limits are in consonance with the Codex Alimentarius recommendation for the maximum Pb content in the sugar.     

高压消解—石墨炉原子吸收光谱法测定贝类中镉含量的条件优化

建立了高压消解—石墨炉原子吸收光谱法测定贝类中镉含量的方法,研究对比几种基体改进剂对海水贝肉中镉原子吸光值的影响,优化了程序升温中灰化及原子化温度。实验结果:采用2 g/L的硝酸钯溶液作为基体改进剂,选择灰化温度650℃,原子化温度1 400℃,方法检出限0.091μg/kg,样品加标回收率90.3%~104.0%,相对标准偏差小于3.5%。试验结果表明该方法线性关系好,检出限、准确度和精密度均满足贝类样品的测定要求。     

Analytical procedure based on slurry sampling for determining selenium in organic vegetable samples by graphite furnace atomic absorption spectrometry

This paper presents a simple, fast and sensitive method to determine selenium in vegetable samples by graphite furnace atomic absorption spectrometry through the direct introduction of slurries of the samples into the spectrometer’s graphite tube. The limits of detection and quantification calculated for 20 readings of the blank of the standard slurries (5 mg mL⁻¹ of microcrystalline cellulose) were 0.33 and 1.10 μg L⁻¹. The proposed method was applied to determine selenium in samples of organically grown vegetables and its results proved compatible with those obtained from samples mineralized by acid digestion in a microwave oven.     

石墨炉法测定食品抗氧化剂TBHQ中铅含量

介绍了国内外食品抗氧化剂TBHQ质量标准中铅限量的规定，认为行标QB2395—1998中铅限量必须修改。同时对TBHQ铅含量采用石墨炉原子吸收光谱法进行了测定，结果表明该法准确性高，数据可靠。     

预富集-冷原子吸收光谱法测定水中的痕量汞

建立了一种预富集-冷原子吸收光谱法测定水中的痕量汞的方法,研究了预富集条件、测定条件等对灵敏度的影响.在最佳的条件下,用这个方法测定水样中的痕量汞,150ml样品中,特征质量为0.01ng/1%,标准偏差为0.0008～0.001,回收率为95.0%～100.0%,结果较为满意.     

石墨炉原子吸收光谱法测定加热卷烟烟草材料中的四种痕量元素

  目的  建立石墨炉原子吸收光谱法（GF-AAS）测定加热卷烟（HTP）烟草材料中铅、镍、铬、镉含量的检测方法。  方法  考察样品前处理条件、灰化温度、原子化温度对检测结果的影响,采用加标回收和重复性试验验证检测结果的准确性和精密度。  结果  （1）四种元素工作曲线线性良好（r2 > 0.999）;（2）Pb、Ni、Cr、Cd加标回收率为93.7%~105.7%,RSD≤5.0%（n=6）,方法检出限分别为0.076、0.025、0.015、0.006 mg/kg。（3）9种加热卷烟烟草材料中Pb、Ni、Cr、Cd元素平均含量分为0.97、1.07、1.28、1.80 mg/kg。  结论  该方法操作简单、成本较低,同时精密度和准确性较高,适用于大批量加热卷烟烟草材料中的4种痕量元素的含量测定。      

正交设计优化石墨炉原子吸收光谱法测定食用盐中的微量铅

建立了食用盐中微量铅的石墨炉原子吸收光谱法,利用磷酸二氢铵-酒石酸作为基体改进剂,针对灰化温度、原子化温度、基体改进剂浓度,通过正交试验优化了铅测定的实验条件,结果表明,其最佳测定条件为：灰化温度为200 ℃,原子化温度为2000 ℃,10 μg·L-1磷酸二氢铵-10 μg·L-1酒石酸混合溶液作为基体改进剂。在该条件下,0 ~ 50 μg·L-1范围内线性关系良好,方法检出限为0.10 μg·L-1,最低浓度下限为0.5 mg·kg-1。并且将方法应用于市售湖盐、海盐、井矿盐等7种样品中铅含量的测定,相对标准偏差为3.9 % ~ 8.0 %,加标回收率为93.7 % ~ 108.8 %,测定结果良好,该研究为快速准确测定食盐中铅含量提供新的参考方法。     

不同前处理方法对石墨炉原子吸收光谱法检测食品中铅含量的影响

目的研究微波消解法、干法消化、湿法消解3种前处理方法对石墨炉原子吸收光谱法检测食品中铅含量的影响。方法以微波消解法为基准,比较其他2种方法的适用性。结果 3种不同前处理方法的检测结果经统计学检验无明显差异,相对标准偏差均小于10%,其中微波消解法的精密度较其他2种方法高,而且加入基体改进剂后回收率及精密度都有了一定的提高。结论 3种不同前处理方法对样品的检测结果没有明显的差异,可以根据实际情况选用。     

Multi-element determination of Cu,Fe, Ni and Zn content in vegetable oils samples by high-resolution continuum source atomic absorption spectrometry and microemulsion sample preparation

The aim of this work was to evaluate the microemulsification as sample preparation procedure for determination of Cu, Fe, Ni and Zn in vegetable oils samples by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS). Microemulsions were prepared by mixing samples with propan-1-ol and aqueous acid solution, which allowed the use of inorganic aqueous standards for the calibration. To a sample mass of 0.5 g, 100 μL of hydrochloric acid and propan-1-ol were added and the resulting mixture diluted to a final volume of 10 mL. The sample was manually shaken resulting in a visually homogeneous system. The main lines were selected for all studied metals and the detection limits (3σ, n = 10) were 0.12, 0.62, 0.58 and 0.12 mg kg⁻¹ for Cu, Fe, Ni and Zn, respectively. The relative standard deviation (RSD) ranged from 5% to 11 % in samples spiked with 0.25 and 1.5 μg mL⁻¹ of each metal, respectively. Recoveries varied from 89% to 102%. The proposed method was applied to the determination of Cu, Fe, Ni and Zn in soybean, olive and sunflower oils.     

石墨炉原子吸收光谱法测定植物提取物中的微量铅

采用石墨炉原子吸收光谱法,在5 mg/mL磷酸二氢铵作为基体改进剂,灰化温度800℃,原子化温度2000℃的条件下,铅标准溶液添加浓度为0.10～1.00 mg/kg时,回收率为95.4%～101.2%,方法检出限为1.2 ng/mL,说明该方法简便快速,灵敏度高,结果准确可靠.