Analy tica zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Chimica Acta, 155 (1983) 159-171 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands zyxwvutsrqponmlkj LIQUID CHROMATOGRAPHIC DETECTION OF CARDIAC GLYCOSIDES, SACCHARIDES AND HYDROCORTISONE BASED ON THE PHOTOREDUCTION OF 2-TERT-BUTYLANTHRAQUINONE M. S. GANDELMAN’ and J. W. BIRKS* Department of Chemistry and Coopemtive Institute for Research in Environmental Sciences (CZRES), University of Colorado, Boulder, CO 80309 (U.S.A.) (Received 27th July 1983) SUMMARY The photoreduction fluorescence detector, a postcolumn liquid chromatographic reaction detector, functions by generating fluorescent products from alcohols, aldehydes, ethers, and amines via a photochemical reaction. The fluorescent product is produced in the photoreduction of 2-tert-butylanthraquinone (t-BAQ) by analytes containing the above-mentioned functional groups. The photochemical reaction only requires t-BAQ to absorb light, and thus many analytes with extremely low ultraviolet-visible absorptivities can be determined with good sensitivity. Because the t-BAQ is added precolumn, no reagent-addition pumps or mixing cells are needed in the detection scheme. The photo- chemical reactor is simply inserted between the liquid chromatographic column and a conventional fluorimeter. To demonstrate the capabilities of the detector involatile com- pounds were chosen (cardiac glycosides, saccharides, and steroids), some of which exhibit extremely low u.v.-visible absorptivities. The detection limits for the cardiac glycosides and hydrocortisone were found to be about 2 ng whereas the detection limits for the sac- charides were about 80 ng. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFE The application of high-performance liquid chromatography (h.p.1.c.) to the determination of compounds lacking chromophores or electrophores is presently limited by the availability of sensitive and selective detectors. Recently, postcolumn reaction detectors have been used successfully to improve the selectivity and sensitivity of conventional h.p.1.c. detectors [l-4] , especially for the determination of nonabsorbing and electrochem- ically inactive compounds. Photochemical reactions have played an active role in the postcolumn reaction detector field [5--151 because they have characteristics that are well suited to postcolumn reactor technology. First, photochemical reactions only require the addition of photons; thus reagent- addition pumps and mixing cells, which cause additional band broadening, are not needed. Second, because many photochemical reactions proceed via free radical intermediates, the reactions are rapid, and lengthy reaction times usually can be avoided. Finally, monochromators and filters can be used to aPresent Address: University of Connecticut, School of Medicine, Farmington, CT 06032, U.S.A. 0003-2670/83/$03.00 o 1983 Elsevier Science Publishers B.V.