Development and Validation of GC-MS Bioanalytical Method to Detect Organic Acidemia in Neonatal/Pediatric Urine Samples

This work was aimed at developing an analytical tool for the simultaneous quantification of methylmalonic acid, glutaric acid, succinyl acetone, homogentisic acid, and pipecolic acid in pediatric urine samples. Organic acids were isolated from urine by liquid-liquid extraction. The extracted samples were then derivatized by using BSTFA + 1% TMCS solution, which resulted in the formation of trimethylsilyl ester derivatives. These analytes were quantified by GC-MS, and this bioanalytical method was validated according to the USFDA guidelines. The proposed method was applied to several clinically suspected organic acidemia samples. The linearity range is within 5 – 100 μg/mL for methylmalonic acid and glutaric acid, 20 – 100 μg/mL for succinyl acetone and homogentisic acid, and 10 – 100 μg/mL for pipecolic acid. Mean % recovery of QC samples of methylmalonic acid, glutaric acid, succinyl acetone, homogentisic acid, and pipecolic acid was found to be 92.06, 92.21, 90.92, 93.17, 90.71%, respectively, and that of tropic acid was 96.57%. All organic acids were stable at room temperature for 8 h. The stability of succinyl acetone, homogentisic acid, and pipecolic acid stored for 30 days at 8°C was found to be lower. The proposed method was applied to the analysis of samples obtained from 23 patients.