De Leo D, Tagliaro F, Maschio S, Marigo M
Z Rechtsmed. 1985;95(1):27-33. doi: 10.1007/BF00203849.
Identification of saliva on stamps or envelope flaps remains yet a not widely studied problem. In most forensic laboratories it is seldom carried out, but this fact does not reduce the importance of the assay. Most authors consider amylase a sufficiently specific marker of the presence of saliva; really, the only other human body fluid that contains high amounts of this enzyme is the pancreatic juice (and therefore feces). Here we present a simple and sensitive assay for the determination of alpha-amylase that uses a commercially available and well-known substrate. It is hydrolyzed by amylase with the production of soluble blue fragments, that can be measured by photometry, obtaining objective results. The presented assay identifies 1 X 10(-6) diluted saliva or that present on 0.5 mg of a stamp; 16-year-old samples can also be identified. Intra-assay and day-to-day CV resulted in 10.8% and 13.7%, respectively. Owing to the high sensitivity of the test, handling samples or reagents can introduce contamination with saliva traces, giving false-positive results. Addition of EDTA 0.1 mol/l to the incubation mixture, lowering the sensitivity to 1 X 10(-3) diluted saliva, overcomes this problem.
邮票或信封封口处唾液的鉴定仍是一个尚未得到广泛研究的问题。在大多数法医实验室中，这项鉴定很少进行，但这一事实并未降低该检测的重要性。大多数作者认为淀粉酶是唾液存在的一个足够特异的标志物；实际上，人体中唯一含有大量这种酶的其他体液是胰液（以及粪便）。在此，我们介绍一种用于测定α -淀粉酶的简单且灵敏的检测方法，该方法使用一种市售且知名的底物。它会被淀粉酶水解，产生可溶的蓝色片段，这些片段可通过光度法进行测量，从而获得客观结果。所介绍的检测方法能够鉴定出稀释至1×10⁻⁶ 的唾液，或存在于0.5毫克邮票上的唾液；16年之久的样本也能被鉴定出来。批内和日间变异系数分别为10.8%和13.7%。由于该检测的高灵敏度，处理样本或试剂时可能会引入唾液痕迹污染，从而产生假阳性结果。在孵育混合物中添加0.1摩尔/升的乙二胺四乙酸（EDTA），将灵敏度降低至稀释至1×10⁻³ 的唾液，可解决这一问题。
