SCP SCIENCE ISO 9001 / ISO 17025 / Guide 34 can prepare custom multi-element calibration standards to exact specifications. Indicate the desired elements and their concentrations, together with the deSCP SCIENCE ISO 9001 / ISO 17025 / Guide 34 can prepare custom multi-element calibration standards to exact specifications. Indicate the desired elements and their concentrations, together with the desired matrix, and the company will recommend a mix stability for a minimum of 12 months (reduced shelf life for concentrations less than 1 ppm). A comprehensive Certificate of Analysis accompanies each standard.sired matrix, and the company will recommend a mix stability for a minimum of 12 months (reduced shelf life for concentrations less than 1 ppm). A comprehensive Certificate of Analysis accompanies each standard.