3-Hydroxymyristic acid as a measure of endotoxin in cotton lint and dust

A series of samples consisting of purified cellulose, purified cellulose spiked with endotoxin, and cotton lint and dust samples from the Human Panel Acute Exposure Studies at Clemson, South Carolina, were extracted with pyrogen-free water and with phenol-water. Phenacyl esters of the dried, hydrolyzed extract were prepared and chromatographed on a high performance liquid chromatograph. A peak assigned to the phenacyl ester of 3-hydroxymyristic acid appears in the chromatograms of extracts of celluloses that have been spiked with endotoxins and not in those of unspiked celluloses. This peak also appears in the extracts of cotton lint from samples that cause the greatest decrement in lung function in the Clemson human exposure studies. The area of this peak increases with increasing amounts of endotoxin and may serve as a measure of endotoxin concentration in cotton lint and dust, at least when fairly high levels of endotoxin (0.50 micrograms or greater) are present. The effect of extraction method on the determined amount of endotoxin is discussed.