A NEW METHOD BASED ON GELATION OF TACHYPLEUS AMEBOCYTE LYSATE FOR DETECTION OF ESCHERICHIA COLIFORM USING A SERIES PIEZOELECTRIC QUARTZ-CRYSTAL SENSOR

A new method utilizing a series piezoelectric quartz crystal (SPQC) se nsor was used to monitor the gelation of Tachypleus amebocyte lysate ( TAL) and this reaction was applied to determine the Escherichia colifo rm (E. coli). The technique depended on the change of conductivity and permittivity during the course of gelation. This method was rapid and sensitive. Some factors affecting the determination were discussed. R esults showed that the frequency shift was linearly related to the log arithm of E. coli concentration in the range of 2.1 x 10(4)-2.1 x 10(8 ) cells/ml. The correlation coefficient is 0.993. This SPQC-TAL method was compared with the standard pour plate counts (PPCs). The proposed method for detection of E. coli is much faster and simpler than the t raditional methods. (C) 1998 Elsevier Science B.V. All rights reserved .