EXTRACTION AND QUANTITATION OF PARAQUAT AND DIQUAT FROM BLOOD

Trace amounts of paraquat and diquat in blood were extracted with phen ol after deproteinization of blood protein with a chloroform:ethanol m ixture and ammonium sulfate. The color reaction of paraquat was achiev ed by addition of alkaline sodium dithionite to the phenolic extract. The blue paraquat radical produced was determined directly by measurem ent of the absorption of the phenol layer. The assay of paraquat (grea ter-than-or-equal-to 0.5 mug) in 1.0 ml of blood (recovery, 93.4%) cou ld be performed within 30 min. Furthermore, simultaneous analysis of p araquat and diquat in the phenolic extract of the sample could be achi eved by use of second-derivative spectroscopy within 30 min.