Development of a GC-MS bio-analytical method to detect organic acidemia in neonatal/ paediatric urine sample

There are some serious congenital disorders and Inborn Errors of Metabolism (IEM), which lead to disability and death of an infant. Most of these congenital disorders have safe and effective management, and if treated early can prevent significant mortality and morbidity. By the time symptoms are manifested, it is often too late and result in severe mental and physical disability in what could have been a completely normal child. There is insufficient epidemiological data to prove the number of cases of IEM in the country. The incidence also increases because of consanguinity prevalent in the country. Often the family suffers because, multiple progeny die from the same disease without proper diagnosis. Analysis of urine organic acid provides information on the metabolism. In this research we have developed and validated a cost effective analytical method using GC-MS for analysis of three organic acids. RTX-5MS (5% phenyl) column was employed with programmed temperature from 50°C to 250°C with a total run time of 19.5 min. A simple extraction technique using ethyl acetate was employed and the derivatization was done in a single step with BSTFA mixture and the analyte in the ratio 1:1. Linearity demonstrated was over a concentration range of 5μg to100 μg with correlation coefficients (r²) 0.994, 0.997, and 0.996 respectively for methyl malonic acid, glutaric acid, and adipic acid. Intra-day accuracy and precision were within the acceptable limits. The mean % recovery of methyl malonic acid, glutaric acid, adipic acid and tropic acid (ISTD) was 92.00, 72.73, 90.26 and 100.69 respectively. The developed method was used successfully to quantify the organic acids in urine samples of paediatric patients.