Gold M, Mathew G
Clin Biochem. 1977 Oct;10(5):191-2. doi: 10.1016/s0009-9120(77)92900-9.
The assay of pregnancy urine estriol by gas chromatography is most often carried out by adding cholesterol as an internal standard at the end of the extraction procedure. The reason for this is that cholesterol does not contain a phenolic ring, and would be lost during the extraction procedure for estriol. This does not allow for corrections of recovery loss, which would be the case if the internal standard was a phenolic steroid. This paper describes the utilization of equilin (delta 1,3,5,7-estratetraen-3-01-17-one) as the internal standard. The sample is hydrolyzed to remove sulfate and glucuronide groups and then the equilin is added. If equilin is added before hydrolysis, variable destruction takes place. Derivative studies indicate that room temperature silylation can be used with bis (trimethylsilyl)-trifluoroacetamide/trichlorosilane/trimethylsilylimidazole, 3:3:2 by weight. Results on control material containing a low, critical pregnancy concentration of estriol were as follows--listed value 5.0 mg/1, found 5.3 mg/1, co-efficient of variation %, 8.9% for 17 runs on different days.
气相色谱法测定妊娠尿雌三醇通常是在萃取过程结束时加入胆固醇作为内标物来进行的。这样做的原因是胆固醇不含酚环，在雌三醇的萃取过程中会损失。如果内标物是一种酚类甾体，就可以校正回收率损失，但胆固醇做内标物则无法做到这一点。本文描述了马萘雌酮（δ¹,³,⁵,⁷ - 雌甾四烯 - 3 - 醇 - 17 - 酮）作为内标物的应用。样品先进行水解以去除硫酸酯和葡萄糖醛酸基团，然后加入马萘雌酮。如果在水解前加入马萘雌酮，会发生不同程度的破坏。衍生化研究表明，室温硅烷化可以使用重量比为3:3:2的双（三甲基硅基）- 三氟乙酰胺/三氯硅烷/三甲基硅咪唑。含有低的、临界妊娠浓度雌三醇的对照物质的检测结果如下——列出的值为5.0毫克/升，测定值为5.3毫克/升，在不同日期进行的17次测定的变异系数为8.9%。
