| abstract |
The invention provides devices, methods, and compositions for dry chemical reagents to measure calcium, magnesium (total hardness), and other analytes in water using colorimetric devices. The measurement may be a one-step procedure without the need of dilution and multi-step preparation, so that it can be easily employed by untrained personnel. The chemical reagents may include dyes, buffer reagents, masking reagents, competing ligands, and other chemicals such as fillers. The chemical reagents may be grinded together as a homogenous fine powder, equally dispensed into small containers for each test or dried as film or solid using the means of air, low heat or vacuum. The composition may be easily dissolved into water samples and stable for long term storage. The methods may be able to distinguish between similar materials such as magnesium and calcium with the same one reagent or from other interfering species in water samples |