气相色谱-燃烧炉-同位素比质谱法测定奶粉中孕酮δ^13C值

Determination of δ^(13)C of progesterone in milk powder by gas chromatography-combustion-isotope ratio mass spectrometry

目的基于高效液相色谱纯化分离,应用气相色谱-燃烧炉-同位素比质谱法(gas chromatography-combustion-isotope ratio mass spectrometry,GC-C-IRMS)建立奶粉中测定孕酮激素碳同位素比值的方法,以气相色谱-质谱法提供定量支持。方法样品经水溶解和乙腈提取,经乙腈饱和的正己烷除脂肪和过C18固相萃取柱净化,经高效液相色谱纯化、浓缩后进行GC-C-IRMS检测。结果外源性孕酮δ^(13)C平均值为-32.297‰,内源性孕酮δ^(13)C平均值为-21.387‰,方法回收率为52.9%,检出限为22.7μg/kg,相对标准偏差小于5%(n=6)。结论内源性和外源性孕酮δ^(13)C值有显著性差异,本方法可以区分内外源性孕酮。但由于方法局限性,只能检测孕酮大于22.7μg/kg的样品。

Objective Based on the separation and purification of high performance liquid chromatography （HPLC）,gas chromatography-combustion-isotope ratio mass spectrometry （GC-C-IRMS） was established for determining the stable carbon isotope ratio of progesterone in milk powder,and gas chromatograph mass spectrometry （GC-MS） was established for determining the residues of progesterone in milk powder.Methods The samples were dissolved in water and extracted with acetonitrile.Then the lipid substances were removed by liquid-liquid extraction with acetonitrile saturated n-hexane.The purification was carried out on a C18 solid phase extraction （SPE） column.The extracts were purified and concentrated by HPLC and detected by GC-C-IRMS.Results Average δ^13C value of endogenous progesterone was-32.297‰ and average δ^13C value of exogenous progesterone was-21.387‰.The recovery was 52.9%,the limit of detection was 22.7 μg/kg and the relative standard deviations （RSDs） were less than 5% （n=6）.Conclusion There is a significant difference in δ^13C value between endogenous and exogenous progesterone,and the method can distinguish endogenous and exogenous progesterone.However,only when the residues of progesterone in powdered milk are more than 22.7 μg/kg,it can be detected by GC-C-IRMS.