A Comparative Study of Methods Used for Analysis of Specific Precipitates in Quantitative Immunochemistry

[摘要] 1. 1. A comparison of the sensitivity and precision of the biuret, ultraviolet absorption, Folin-Ciocalteu and ninhydrin methods for the analysis of specific precipitates has been made, and the uses and limitations of each have been discussed.2. 2. The ultraviolet absorption of samples in 0.25 N acetic acid and the biuret methods were found to be simple and accurate, the limits of 2 S. D. being ±5 to 10%. The former may be used for samples containing as little as 5 μg nitrogen whereas the lower limit of the latter is about 20′ μg nitrogen.3. 3. The Folin-Ciocalteu method may be used for samples as small as 5 μg nitrogen and 2 S.D. equals ±15%.4. 4. The ninhydrin method has a sensitivity making it capable of determining as little as one microgram of protein nitrogen but for reproducible results should probably not be employed without the use of a standard.

[学科分类] 生物科学（综合）