A new HPLC micromethod to measure total plasma homocysteine in newborn

Total plasma homocysteine (tHcy) in children may be an useful biochemical m arker for genetic risk of premature cardiovascular disease. We reported a r apid, isocratic HPLC method able to process very small amount of newborn pl asma samples. A blood sample from heel capillary circulation was collected, using a heparinized capillary glass tube. Plasma sample from 1 to 10 mul w as derivatized with ammonium-7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate a fter reduction with tri-n-butylphosphine and analyzed on Discovery C18 colu mn, with a solution of acetonitrile-dihydrogenphosphate 0.1 M (8:92 v/v pH* 2.1). This assay ensures a good recovery (95%), precision (CV 4.5%) and lin earity (y = 2.41x + 0.31, r = 1). Due to its simplicity and reliability, ou r method is suitable for routine analysis of tHcy and other aminothiols (Cy s, Cys-Gly, GSH) assessed for clinical and research purposes. With this HPL C method we have assayed tHcy levels in 1400 apparently healthy newborn bab ies (tHcy mean value = 4.9 +/- 2.7 muM). In conclusion, this accurate and l inear HPLC method allows measurement of tHcy in newborn during the routinar y capillary blood collection in the fourth living day without any other inv asive procedure. (C) 2001 Elsevier Science B.V. All rights reserved.