Each of the chemicals in GRAS Screen 1 and 2 have been used under one or more of the following categories. As (1) a Generally Recognized As Safe (GRAS) substance, (2) a pharmaceutical excipient, (3) a normal physiological constituent, (4) a metabolic byproduct, and/or (5) a Everything Added to Food in the United States (EAFUS) substance.

GRAS Screen 1 samples four low molecular weight Polyethylene glycols (300, 400, MME 550, and 600) versus twenty-four salts, encompassing pH 4-9. GRAS Screen 1 is supplied in a 96 Deep Well block format and is compatible with robotic and multi-channel pipet liquid handling systems. GRAS Screen 1 is compatible with vapor diffusion, free interface diffusion, and microbatch crystallization methods. For research use only.

GRAS Screen 2 samples four medium molecular weight Polyethylene glycols (1,000, MME 2,000, 3,350, & 4,000) versus twenty-four salts, encompassing pH 4-9. GRAS Screen 2 is supplied in a 96 Deep Well block format and is compatible with robotic and multi-channel pipet liquid handling systems. GRAS Screen 2 is compatible with vapor diffusion, free interface diffusion, and microbatch crystallization methods. For research use only.