目的 建立拉曼光谱内标法快速测定煅石膏中无水硫酸钙的含量。方法 内标物为硝酸钠，波长为780 nm，激光功率为24 mW，光阑为50 μm slit，物镜为10倍，曝光时间为2 s，累积次数为2次，扫描范围为300～1700 cm^-1。结果 无水硫酸钙质量分数在5%～35%与无水硫酸钙和硝酸钠的拉曼特征峰强度比（I₁₀₁₆/I₁₀₆₈）线性关系良好；低、中、高3个质量分数的平均加样回收率分别为101.4%、100.9%、100.6%，RSD分别为1.7%、0.8%、0.9%。结论 该方法简便、快速、重复性好，可用于煅石膏药材的质量评价。

Objective To establish an internal standard method for rapid determination of anhydrous calcium sulfate in calcined gypsum by Raman spectroscopy. Method Internal standard:sodium nitrate; excitation wavelength:780 nm; laser power:24 mW; aperture:50 μm slit;lens:10×objective; exposure time:2 s; accumulation:2 times; scanning range:300-1700 cm^-1. Results The peak intensity ratio (I₁₀₁₆/I₁₀₆₈) was used for the quantitative evaluation of calcined gypsum level and showed a good linear relationship with mass fraction of anhydrous calcium sulfate in the range of 5%-35%. The average recoveries at low, medium and high concentrations were 101.4%, 100.9% and 100.6%, with RSD of 1.7%, 0.8% and 0.9%, respectively. Conclusion The method is simple, rapid and reproducible. It can be used for the quality evaluation of calcined gypsum.

R286

国家重点研发计划资助（2018YFC1707000）