Used primarily in analytical chemistry to detect and quantify malondialdehyde (MDA), a marker for lipid peroxidation and oxidative stress in biological samples. The reaction between 2-thiobarbituric acid and MDA produces a pink-colored complex that can be measured spectrophotometrically, making it a key method in studies of oxidative damage in cells, tissues, and food products. Also applied in the assessment of antioxidant activity and in monitoring spoilage in meat and other lipid-containing foods due to its sensitivity to rancidity. Additionally, it has been used in the synthesis of heterocyclic compounds and in some pharmaceutical intermediates.