Spectra interference between diquat and paraquat by second derivative spectrophotometry.

Area of Science:

• Analytical Chemistry
• Environmental Chemistry
• Toxicology

Background:

• Diquat (DQ) and paraquat (PQ) are toxic herbicides requiring sensitive detection methods.
• Existing methods for DQ and PQ analysis can be time-consuming or lack simultaneous detection capabilities.
• Accurate quantification of DQ and PQ in biological matrices is crucial for clinical diagnosis and environmental monitoring.

Purpose of the Study:

• To develop and validate a rapid, accurate, and simultaneous method for determining DQ and PQ in biological samples.
• To establish a sensitive analytical technique for DQ and PQ detection in blood, tissue, and urine.
• To assess the method's performance, including detection limits, recovery, and precision.

Main Methods:

• Solid-phase extraction (SPE) using Wakogel gel for sample cleanup.
• Second-order derivative spectrophotometry for simultaneous quantification of DQ and PQ.
• Protein precipitation with trichloroacetic acid for plasma and tissue samples.
• Urine treatment with Amberlite IRA-401 resin prior to SPE.

Main Results:

• The method achieved simultaneous determination of DQ and PQ in plasma, tissue, and urine.
• Detection limits were as low as 0.001 mg/l for PQ in urine and 0.005 mg/l for PQ in plasma.
• High recoveries (93% for DQ, 85% for PQ) and good precision (3.2-4.6%) were obtained.
• Negligible interference was observed within a specific DQ/PQ concentration ratio.

Conclusions:

• The developed method offers a rapid and accurate approach for simultaneous DQ and PQ determination.
• This technique is suitable for routine analysis of DQ and PQ in clinical and forensic toxicology.
• The method's sensitivity and reliability make it valuable for monitoring herbicide exposure.