Bacterial spore detection and determination by use of terbium dipicolinate photoluminescence

A new method to detect bacterial endospores and determine their concentration was demonstrated by the addition of a solution of terbium chloride to a suspension of bacterial endospores. The terbium chloride reacted with the calcium dipicolinate in the spore case to form terbium(III) dipicolinate anion. Solid particles, including residual bacterial particles, were removed by filtering. The photoluminescence from the solution was measured as a function of excitation wavelength, emission wavelength, and bacterial endospore concentration. The photoluminescence from terbium(III) dipicolinate anion in the solution was easily identified.