Single-use test materials used to rapidly and semi-qualitatively determine the acidity or alkalinity of liquids or to measure another parameter or substance; may include tests for starch, chlorine, and molybdenum; usually via the use of color-based reactions.

pH Papers, pH strips, pH sticks, and pH test kits are used in laboratory, industrial, and educational environments to qualitatively assess pH levels or monitor acid-base titrations in a range of sample types.pH Buffer reference standards are used for the accurate calibration of pH meters and monitors for far more precise and quantitative pH measurement.

pH Test papers are supplied either as rolls, tear-off strips, or sticks. They are impregnated with indicator dyes that change color at a specific pH. In some products, indicator dyes are covalently linked to cellulose fibers to avoid bleed-out (leaching) and contamination of the test sample.

Some pH papers indicate simple acid or base conditions with a single red-to-blue color change (also called litmus papers). Universal pH papers and strips contain a combination of indicators that cover a range of pH values up to and including 0 to 14 in a single test. The observed color change is checked against a comparison chart supplied with the papers.

Alternatively, for metered assessments of pH, standard or reference pH buffers are used to calibrate pH meters and other electrochemical sensors.