1.1 ,This test method is used for the determination of free formaldehyde (HCHO) in emulsion polymers without upsetting existing formaldehyde equilibria. The procedure has been evaluated using acrylic, acrylonitrile-butadiene, carboxylated styrene-butadiene and polyvinyl acetate emulsion polymers. This test method may also be applicable for emulsion polymers of other compositions. The established working range of this test method is from 0.05 to 15 ppm formaldehyde. Emulsion polymers must be diluted to meet the working range.