Indirect Fluorescence Detection of Amino Acids on Electrophoretic Microchips

摘要

Microfabricated devices enable rapid separations of a variety of clinically significant analytes, including DNA. proteins, and amino acids. However, absorbance detec-iOn has been difficult to achieve on these devices, prohibiting analysis of nonfluorophore-bearing or non-&iorescently tagged analytes. An alternative detection ~cJbnique exploiting indirect fluorescence has been adapted ~ the electrophoretic microchip to provide fast analysis damino acids, bypassing the need for absorbance detec-ion or fluorescence derivitization procedures. Nineteen d the standard amino acids could be detected with an average detection limit of 32.9 pM (--‘1.6 amol). Despite lie lhct that the detection sensitivity was lower thai that achievable by labeling the amino acids with finorescein bothiocyanate (--‘1 nM), circumventing sample pv~para-ion and the difficulties inherent with t~ng compleK mnples make this technique attractive for a variety of hhays where sensitivity is not critical. To demonstrate the malicability to real sample matrixes, the analysis of urine elevated amino acid levels is used as a model syatem where the elevated levels are indicative of a variety of pathologies including amino acid metabolism disorders aid kidney malfunction. The minimal sample handling d rapid separations achievable by employing indirect detection on microchips provides the potential for high-roughput applications for certain amino acid analyses.