Abstract: A method and a solid phase calibrant are provided suitable for use by untrained personnel to calibrate an analytical instrument under field conditions away from a laboratory. Filter discs or other suitable substrates are impregnated, by the process of adsorption, with solutions of known concentrations of analytes and chromatographic phase materials, such as polymers, in suitable solvents. The substrate material is selected to be chemically inert and to not negatively interact with the analytes, the calibration process, or the analytical instrumentation. The polymers cause the analyte to adhere to the substrate until the solution is desorbed by heating, so that the impregnated substrates form stable calibration solutions in solid phase which can be easily and reliably stored, transported, and used by operators with minimal training. The substrate is preferably contained in a card holder which can be easily inserted into and preferably mate with an inlet for the analytical instrument.