[Rapid method of determining the dry mass of whooping cough microbes]

A colorimetric method for the rapid determination of the quantitative content of microbial mass in B. pertussis suspensions has been developed. The method is based on the indirect determination of carbon in microbial suspensions by its oxidation with the mixture consisting of potassium bichromate in concentrated sulfuric acid and the subsequent colorimetric analysis of the products of this reaction. The method ensures sufficient accuracy, the determination procedure is simple, takes not more than 2 hours and requires no complex reagents. The results thus obtained are well comparable with those obtained by the classical gravimetric method. The new method permits the determination of microbial mass in B. pertussis suspensions with a minimum concentration of 0.5 mg/ml. The method is recommended for the determination of dry microbial mass in B. pertussis suspensions.