SIMULTANEOUS QUANTITATIVE 1H NMR ANALYSIS OF METHANOL, ETHANOL AND THEIR METABOLIC PRODUCTS IN HUMAN PLASMA: EARLY DIANOSIS AND MONITORING DURING TREATMENT OF ACUTE METHANOL POISONING IN VIETNAM

The H-1-NMR method for simultaneous quantification of methanol, ethanol and their metabolic products (formic acid and acetic acid) in human plasma was established. The effect of protein in plasma sample was removed by 25% trichloroacetic acid (TCA) with the ratio of TCA and plasma sample at 1/5 (v/v). The small amount of D2O (estimated 1/10 v/v) was chosen due to the effect of water signal was eliminated by using the advance water suppression with NOESY pulse sequence. The different analytical parameters such as linearity, precision, accuracy, and specificity, instrument detection limit (IDL) and instrument quantification limit (IQL) were validated. The instrument detection limit of four compounds in blank plasma varied from 0.68 (for methanol) to 2.88 mg/L (for formic acids). The average recoveries of concentration in dynamic ranges were found to be 96 to 105%. The good linearity between concentration calculated by integrated signal and measured obtained by calibration curves confirmed that concentration of analytes in plasma can be directly determined from the H-1-NMR signal. The proposed method has been successfully applied for direct determination of five compounds in 9 patient's plasma samples with the satisfactory results compared to GC/FID method. The analytical procedure can be useful for diagnosis and evaluation of treatment of methanol poisoning in Vietnamese hospitals.