Craft N E, Brown E D, Smith J C
University of Maryland, College Park 20742.
Clin Chem. 1988 Jan;34(1):44-8.
We investigated the effects of storage and handling on measured values for carotenoids, retinol, and tocopherol in plasma. We found no significant differences in the concentrations of these analytes measured in plasma samples that were frozen immediately after separation as compared with replicate samples maintained at room temperature in the dark for 24 h. Analytes were stable in solvents for at least 18 h at 23 degrees C after extraction. Purging samples with nitrogen gas before freezing had no detectable beneficial effects. All analytes were stable in plasma stored at -70 degrees C for at least 28 months or at -20 degrees C for five months. By 15 months the concentrations of carotenoids were significantly less (P less than 0.05) in plasma stored at -20 degrees C than in plasma stored at -70 degrees C, while retinol and tocopherol concentrations were not significantly different. Concomitant with the decrease in carotenoids was the appearance of unidentified peaks in the ultraviolet. Adding ascorbic acid or butylated hydroxytoluene antioxidants to the precipitating solvent did not alter the losses of carotenoids or alter the appearance of unidentified peaks. Under appropriate conditions, plasma carotenoids, retinol, and tocopherol are stable for more than two years.
我们研究了储存和处理对血浆中类胡萝卜素、视黄醇和生育酚测量值的影响。我们发现，与在黑暗中室温下保存24小时的重复样本相比，分离后立即冷冻的血浆样本中这些分析物的浓度没有显著差异。提取后，分析物在23摄氏度的溶剂中至少稳定18小时。冷冻前用氮气吹扫样本没有可检测到的有益效果。所有分析物在-70摄氏度储存至少28个月或在-20摄氏度储存五个月的血浆中都很稳定。到15个月时，-20摄氏度储存的血浆中类胡萝卜素的浓度比-70摄氏度储存的血浆中显著降低（P小于0.05），而视黄醇和生育酚的浓度没有显著差异。随着类胡萝卜素的减少，紫外线下出现了不明峰。在沉淀溶剂中添加抗坏血酸或丁基化羟基甲苯抗氧化剂不会改变类胡萝卜素的损失，也不会改变不明峰的出现。在适当条件下，血浆中的类胡萝卜素、视黄醇和生育酚可稳定两年以上。
