Trichloroacetic acid (TCA) is widely used in analytical chemistry as a standard sample for calibration and quality control in environmental, pharmaceutical, and clinical testing laboratories. Its primary application lies in the validation of analytical methods, especially in chromatography and spectrometry, where precise quantification of acidic compounds is required. TCA serves as a precipitating agent for proteins in biological samples, enabling the isolation of nucleic acids or small molecules during sample preparation. This makes it valuable in molecular biology and biochemistry workflows where clean, protein-free extracts are needed. In environmental analysis, TCA is used as a reference standard to detect and quantify halogenated organic compounds in water and soil samples, particularly those formed during disinfection processes or industrial pollution. It helps ensure accurate monitoring of disinfection byproducts such as haloacetic acids. Due to its stability and well-defined chemical behavior, TCA is also employed in method development and inter-laboratory comparisons to maintain consistency and reliability in test results across different laboratories and instruments.