This work describes the use of electrothermal atomic absorption spectrometry in combination with a pyrolytic graphite-coated tube with a platform for trace arsenic (As) determination in titanium dioxide (TiO2) pigment. This type of matrix is challenging, as complete digestion in hydrofluoric acid-containing solution is needed. First, closed-vessel microwave digestion was performed for the full-sample decomposition. Next, a temperature program was optimized for drying, pyrolysis, and atomization temperatures. Furthermore, the use of a chemical modifier mixture was proposed that reduced the background contribution and prevented significant analyte loss and therefore improved the analytical procedure. The optimized method was validated for the detection (LOD) and quantification (LOQ) limits, the linear concentration range, accuracy, and precision. Special attention was devoted to the matrix-matching solutions in the calibration procedure. Linearity was confirmed in the 5.0 to 100.0 µg/L concentration range (R2 = 0.999). The average recovery for 16 different real TiO2 pigment samples was 92.0%, and the relative standard deviation value for six replicate measurements was ≤10.4%. Moreover, the LOD and LOQ in terms of the TiO2 pigment mass was determined to be 0.2 µg/(g TiO2) and 0.7 µg/(g TiO2), respectively. The latter complies with Commission Directive 2008/128/EC, which does not allow more than 3 µg As/(g product) as the specific criteria of purity. Finally, based on scanning electron microscopy analysis of unused and several times used pyrolytic graphite-coated tubes, usage of the tube 250 times before replacement is recommended.

中文翻译：

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使用电热原子吸收光谱法测定 TiO2 颜料基质中的痕量砷。

这项工作描述了电热原子吸收光谱法与热解石墨涂层管的结合使用，该管带有一个平台，用于测定二氧化钛 (TiO2) 颜料中的痕量砷 (As)。这种类型的基质具有挑战性，因为需要在含氢氟酸的溶液中完全消解。首先，对全样品分解进行密闭容器微波消解。接下来，针对干燥、热解和雾化温度优化温度程序。此外，建议使用化学改性剂混合物，以减少背景影响并防止显着的分析物损失，从而改进分析程序。对优化方法的检测 (LOD) 和定量 (LOQ) 限值、线性浓度范围、准确度和精密度进行了验证。特别注意校准程序中的基质匹配溶液。在 5.0 到 100.0 µg/L 的浓度范围内确认了线性 (R2 = 0.999)。16 种不同的真实 TiO2 颜料样品的平均回收率为 92.0%，六次重复测量的相对标准偏差值≤10.4%。此外，根据 TiO2 颜料质量确定的 LOD 和 LOQ 分别为 0.2 µg/(g TiO2) 和 0.7 µg/(g TiO2)。后者符合委员会指令 2008/128/EC，该指令不允许超过 3 µg As/(g product) 作为纯度的具体标准。最后，基于对未使用和多次使用过的热解石墨涂层管的扫描电子显微镜分析，建议在更换前使用 250 次。