Blanchard J, Weber C W, Shearer L E
Department of Pharmaceutical Sciences, College of Pharmacy, University of Arizona, Tucson 85721.
J Chromatogr Sci. 1990 Dec;28(12):640-2. doi: 10.1093/chromsci/28.12.640.
A sensitive and specific high-performance liquid chromatographic (HPLC) procedure is developed for simultaneously quantitating the levels of caffeine, theophylline, theobromine and paraxanthine in breast milk. The method involved the precipitation of proteins present in the milk samples with a 6% v/v perchloric acid solution containing the internal standard, proxyphylline, followed by centrifugation at 12,800 Xg for 10 minutes. The clear supernatant was then chromatographed on a C18 reversed-phase analytical column at ambient temperature using a wavelength of 272 nm. Samples were eluted from the column at a constant flow rate of 1.5 mL/min using a gradient program in which the concentration of methanol in the mobile phase varied from 0 to 16%. The mean recoveries of the methylxanthines averaged over all the concentrations examined were generally excellent and ranged from 96.3 +/- 5.4% for caffeine to 102.3 +/- 8.9% for paraxanthine. The assay precision was very good and the peaks of interest were extremely well resolved. The method is recommended for assessing the total caffeine and dimethylxanthine load to which the nursing infant is exposed in mothers ingesting typical amounts of caffeine.
开发了一种灵敏且特异的高效液相色谱（HPLC）方法，用于同时定量母乳中咖啡因、茶碱、可可碱和副黄嘌呤的含量。该方法包括用含有内标物丙羟茶碱的6%（v/v）高氯酸溶液沉淀母乳样品中的蛋白质，然后在12,800×g下离心10分钟。然后将清澈的上清液在室温下于C18反相分析柱上进行色谱分析，使用波长为272nm。使用梯度程序以1.5mL/min的恒定流速从柱上洗脱样品，其中流动相中甲醇的浓度从0变化到16%。在所检测的所有浓度下，甲基黄嘌呤的平均回收率总体良好，咖啡因的回收率为96.3±5.4%，副黄嘌呤的回收率为102.3±8.9%。该测定精密度非常好，目标峰分离效果极佳。推荐该方法用于评估摄入典型量咖啡因的母亲的哺乳婴儿所接触的总咖啡因和二甲基黄嘌呤负荷。
