Evaluation of concentration procedures of mutagenic metabolites from urine of diesel particulate-treated rats.

Several concentration procedures of mutagenic metabolites contained in the urine of diesel particulate-treated rats were compared. Mutagenicity was monitored by the Salmonella/microsome assay. The procedures tested were: lyophilization; filtration on XAD-2, XAD-7 or Sephadex LH-20 matrices; ultrafiltration; and extraction with organic solvents. Urine extraction with dichloromethane (DCM) gave almost quantitative recovery of activity while leaving salts and other polar compounds in the aqueous phase, and is the method recommended.