Analysis of Diglycolic Acid after Mass Poisoning by Diethylene Glycol

In December 2019, unusual cases of acute renal failure with neurological changes were observed in the State of Minas Gerais, Brazil. Criminal investigations indicated cases of intoxication after consumption of beers contaminated with diethylene glycol (DEG). The elimination of DEG by the body is fast, but its metabolite, diglycolic acid (DA), may persist for a long time. To assess the level of intoxicated victims who consumed the contaminated beers, qualitative and quantitative methods were developed to determine DA in biological matrices by gas chromatography coupled to a mass spectrometer (GC-MS) and gas chromatography coupled to a mass spectrometer with triple-quadrupole mass filter (GC-MS-MS), respectively. The validated qualitative method presents good selectivity and limit of detection of 1 µg/mL (whole blood, urine, vitreous humor and cerebrospinal fluid) and 5 µg/g (liver and kidney), respectively. A quantitative method for whole blood presented satisfactory performance to determine DA. Twelve victims presented positive results for DA in whole blood, with concentrations ranging from 2 to 108 µg/mL. The toxicology laboratory of the Institute of Forensic Medicine of Minas Gerais was the first governmental agency to identify DA in whole blood, vitreous humor, cerebrospinal fluid, kidney and urine in victims affected by this contaminant. The results of this study legally supported the prohibition of the continued consumption of the beer and avoided further intoxications. Our results showed, for real cases of human intoxication, that DA can still be detected in alternative matrices, even when non-detectable in blood, demonstrating the importance of collecting different kinds of samples for a proper investigation.