Simple sensitive solid-phase extraction of paraquat from plasma using cyanopropyl columns

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Toxicology

Background:

• Paraquat poisoning is a significant clinical concern requiring accurate and accessible diagnostic methods.
• Existing paraquat quantitation methods may be complex or costly, limiting their widespread use.

Purpose of the Study:

• To develop and validate an inexpensive, sensitive, and simple method for paraquat quantitation in human plasma.
• To establish the assay's linearity, limit of quantitation, and assess potential interferences.

Main Methods:

• A cyanopropyl extraction method followed by colorimetric detection using sodium dithionite.
• Paraquat is extracted from plasma, eluted, neutralized, and reacted to produce a measurable color.
• Absorbance is measured at specific wavelengths (A395-A460) to determine paraquat concentration.

Main Results:

• The assay is linear up to 4.35 microM paraquat with a lower limit of quantitation of 0.23 microM.
• Lipemic and icteric samples did not interfere, but hemolysis caused a slight elevation in measured paraquat.
• Diquat showed minimal interference, and coefficients of variation were generally low, indicating good precision.

Conclusions:

• The developed method offers a cost-effective and sensitive approach for paraquat determination in plasma.
• This assay is suitable for routine clinical toxicology screening and monitoring.
• Further validation may be needed to fully account for potential interferences like hemolysis.