Zero Grade Gases

A zero gas is normally a pure gas that does not contain the component to be measured, and it should be as similar to the matrix of the measured sample as possible. The purity of the zero gas used to set the zero point on analytical instrumentation is critical and must be sufficiently high for the application in question. Contamination of zero gases can significantly influence the results of analytical measurements. Impurities occurring in concentrations as low as parts per billion can have serious consequences, particularly if the impurities are part of the sample to be analysed or if the analyst is not sure which molecules are present in the sample.