Patent ID: 6225128
Filing Date: 2001-05-01
Classification: G01N

Abstract:
A method for producing a color test card for visually indicating the presence or absence of lead in material applied thereto, said method comprising the steps of:dissolving a solid rhodizonic acid dipotassium chromogent salt in an alcohol solvent to produce a liquid mixture of salt and solvent;feeding said mixture drop by drop through a pipette onto a flat dry test card to form at least one circular area of a coating of said mixture while the solvent is evaporating;heating said card in a microwave oven to drive off any entrained air moisture as well as any solvent remnant, the heating process being continued until just before the card begins to char; andinserting the dried coated card with a small amount of desiccant into a plastic envelope which is immediately sealed, this amount being only necessary to absorb any water moisture contained in the air at the instant when the card is inserted so that the card remains completely dry.