pH值影响细菌内毒素测定的实验室研究

 目的：研究样品pH对细菌内毒素测定的影响。方法：应用动态浊度法定量测定样品中细菌内毒素的含量；由细菌内毒素参考标准品(RSE)制成两种浓度的稀释液，在14个pH量级上，与国内外两种鲎试剂(TAL,Tal)反应；观察每组平均回收率。结果：pH梯度上，两种鲎试剂回收曲线都呈现三个反应高峰，分别为pH5.20,pH7.83/pH6.23和pH10.55。样品pH在6～8间实验结果稳定，4λ阳性对照的平均回收率为76.5%～115.9%和85.8%～99.8%；当样品pH值≤3或≥12时，细菌内毒素试验受到抑制，平均回收率≤56.8%。结论：细菌内毒素试验中应该调节检品pH；使用TAL时，检品pH应预调在(6.5～7.5)为好；使用LAL时，检品pH应预调在(6.2±0.1)或(6.7～7.8)为好。

Effects of various pH in testing bacterial endotoxins

OBJECTIVE: To study the effect of samples having different pH values in the bacterial endotoxins test (BET). METHODS: The BET was conducted as an assay of the concentration of endotoxins by using kinetic-turbidimetric technique. Samples having different pH values but containing same concentration reference standard endotoxin (RSE) were tested by TAL/LAL reagents. The average result on the standard curve was calculated and the mean recovery observed. RESULTS: The reagents had three highly sensitivities in pH 5.20, pH 7.83/pH 6.23 and pH 10.55. After adjustment to pH 6 to 8, the mean recovery was 76.5%～115.9% or 85.8%～99.8%. When the sample pH value was less than 3 or more than 12, the test was unsuitable for the inhibition test, and the mean recovery was less than 56.8%. CONCLUSION: It is necessary to adjust the pH of the solution to be tested in the BET, adjust the sample to pH (6.5～7.5) when using TAL reagents, and adjust to pH (6.2±0.1) or pH(6.7～7.8) when using LAL reagents.