三重串联四极杆电感耦合等离子体质谱法测定植源性中药材中总硫含量

针对日益严重的植源性中药材中二氧化硫（SO₂）浓度超标问题，研究基于最新的三重串联四极杆电感耦合等离子体质谱（ICP-MS/MS）技术建立了一种快捷、准确的二氧化硫检测方法。该方法可以有效地降低背景中多原子离子的干扰，提高检测灵敏度与标准曲线的线性范围。使用氧气作为反应气，对32S16O2-₄和34S16O2-₄的检出限分别为5.48和9.76 μg·L-1，线性范围0.02～100 mg·L-1(r> 0.999）。0.5 g中药样品加入6 mL硝酸和2 mL双氧水，使用微波消解方式对样品进行消解。选用柑橘叶标准参考物质对方法的可靠性进行考察，样品平行处理测定6次后所得浓度值在标准值范围内。结果表明，本方法可以实现中草药中SO₂浓度的准确测定，样品处理过程以及样品中背景元素不会对定量结果的准确性产生干扰。

Determination of Total Sulfur Dioxide in Chinese Herbal Medicines via Triple Quadrupole Inductively Coupled Plasma Mass Spectrometry

As an important treatment method ,sulfur fumigation plays an essential role in the production and preservation of traditional Chinese herbal medicines .Although there is strict regulation on the use of sulfur dioxide ,the abuse of sulfur dioxide still occurred from time to time .And the public faces a high risk of exposure .Because of the poor precision and tedious prepara-tion procedures of traditional recommended titration ,the accurate and convenient determination of sulfur dioxide in Chinese herb-al medicines is still a critical analytical task for medicines safety and the public health .In this study ,an accurate ,high-through-put ,and convenient method for the absolute determination of SO2 in Chinese herbal medicines based on triple quadrupole induc-tively coupled plasma mass spectrometry (ICP-MS/MS) technique is developed .The study compared the quantitative ability for sulfur when the ICP-MS operated under traditional single quadrupole (QMS) mode and novel triple quadrupole (MS/MS) mode with three Reaction/Collision cell condition (no gas ,helium ,and oxygen) .The result indicated that when the concentration of sulfate ranging from 0 .5 to 100 mg · L -1 ,isotopic 34 S can be selected as quantitative ion either the ICP-MS operated under the QMS mode or MS/MS mode .The use of helium in the Reaction/Collision cell decreased the single intensity of background ions . Better than QMS mode ,the MS/MS mode can effectively reduced background interference .But there are no significant differ-ences about the linear range and limit of detection .However ,when the ICP-MS operated under MS/MS mode and oxygen was used as reaction gas in the Reaction/Collision cell ,the ICP-MS/MS provided an interference-free performance ,the linear range and limit of detection improved significantly .Either 32S or 34S exhibits an excellent linearity (r>0.999) over the concentration range of 0 .02~100 mg · L -1 ,with a limit of detection of 5.48 and 9.76 μg · L -1 for 32S16O2 -4 and 34S16O2 -4 ,respectively .The Chinese herbal medicines was treated using microwave digestion added 6 mL nitric acid and 2 mL hydrogen peroxide before analy-sis .The amount of nitric acid and hydrogen peroxide were optimized .The method was validated using Chinese herbal standard reference material GBW10020 .The sample was treated and detected in six parallel ,and the average concentrations obtained u-sing the developed method (0.42% ± 0.01% ) is in excellent agreement with the standard concentration (0.41% ± 0.03% ) .The study demonstrates an accurate and convenient approach for the quantification of SO 2 in Chinese herbal medicines .