In one case, a laboratory was extracting 500 mL of highly contaminated sludge with 500 mL of solvents. The laboratory was able to reduce the sample and extraction solvent volumes to 100 mL each while maintaining the desired sensitivity limits. This reduct ion affected two waste streams in the laboratory- waste hazardous sample material and waste solvent. When the use of hazardous materials cannot be avoided, carrying an experiment out on a microscale limits the quantity of hazardous waste produced. Another impetus to the use of small-scale reactions is the fact that glassware that cannot be cleaned and reused is itself regulated as a hazardous waste if contaminated with hazardous materials.
Many analytical procedures involve hazardous reagents and products that result in hazardous waste.
To minimize the hazardous waste problems in such operations, the specific solvent to be used and the feasibility of recycling it must be carefully considered. Many organic and inorganic synthesis procedures have been successfully designed so that the product of one synthesis is the starting material for the next. Multi-step sequences have been designed for a variety of syntheses. When each step is complete, characterizing procedures are carried out on a few milligrams of material. The bulk of the material continues in the process so that no product from the earlier steps is left to be disposed of or to be stored.