Thermospray high performance liquid chromatography/mass spectrometric identification of a bladder carcinogen metabolite isolated from guinea pig urine

An in vivo uninary metabolite of the bladder carcinogen 2‐amino‐4‐(5‐nitro‐2‐furyl) thiazole was isolated from guinea pig urine and was identified by direct analysis using thermospray mass spectrometry/high‐performance liquid chromatography as 1‐(2‐amino‐4‐(5‐nitro‐2‐furyl)‐2‐thiazolyl)‐1‐deoxy‐β‐D‐glucopyranuronic acid. The structure of this metabolite was also established by chemical synthesis. Both positive and negative ion thermospray mass spectrometry of the conjugate showed fragment ions resulting from cleavage across the pyran ring of the glucuronic acid comprising of aglycone moiety. These characteristic fragment ions may be diagnostic for identification of N‐glucuronides from O‐glucuronides.