Chemical assays are laboratory methods used to determine the presence and concentration of specific substances in a sample. These tests can analyze various materials, including liquids, solids, and gases, to identify chemical compounds or measure their quantities. Common techniques include titration, spectroscopy, and chromatography. Assays are essential in many fields, such as pharmaceuticals, environmental science, and food safety. They help ensure product quality, monitor environmental pollutants, and verify the composition of food items. By providing accurate and reliable data, chemical assays support research, regulatory compliance, and public health initiatives.