Ethylene glycol and propylene glycol are the primary ingredients in commercially available antifreezes. They are used with various corrosion inhibitors to protect metal surfaces in cooling water systems. CHEMetrics' glycol test kits, which employ a chemistry perfected by CHEMetrics, are used to monitor potable waters for contamination from glycol originating in cooling systems. Stricter limits for storm water effluent glycol discharges are expected from the USEPA. In addition to the glycol recycling operations, monitoring the efficiency of recovery and collection systems is crucial. In the colorimetric chemistry, periodic acid oxidizes ethylene glycol and/or propylene glycol to formaldehyde, which reacts with Purpald in alkaline solution. Visual and instrumental test kits are available that report test results in either ppm (mg/L) ethylene or propylene glycol. Correction factors are supplied with all kits to convert test results to the alternate glycol form. This test requires much less time to perform and involves fewer manipulations than the standard chromotropic acid procedure. Refrigeration will dramatically increase the shelf life of these products. Shelf life: six months. We recommend stocking quantities that will be used within five months.