Comparison of analytical methods for metribuzin

Area of Science:

• Agricultural Chemistry
• Analytical Chemistry

Background:

• Accurate quantification of active ingredients in pesticides like metribuzin is crucial for efficacy and regulatory compliance.
• Various analytical techniques exist, but their suitability and accuracy can vary depending on the compound and solvent used.

Purpose of the Study:

• To compare the accuracy and reliability of different analytical methods for determining the active ingredient content in technical and formulated metribuzin.
• To identify the most suitable solvent for gas-liquid chromatography (GLC) analysis of metribuzin.

Main Methods:

• Comparative analysis of metribuzin active ingredient using gas-liquid chromatography (GLC) with different solvents (including ketones, ethylene glycol monomethyl ether, and methylene chloride).
• Infrared (IR) spectrophotometry.
• High-pressure liquid chromatography (HPLC).

Main Results:

• Ketone solvents were unsuitable for GLC analysis due to Schiff base formation.
• The GLC method using ethylene glycol monomethyl ether yielded results approximately 1% higher than other methods.
• GLC analysis using methylene chloride solvent demonstrated strong agreement with IR spectrophotometry and HPLC, with deviations within 0.4%.

Conclusions:

• Gas-liquid chromatography using methylene chloride is the preferred method for accurate determination of metribuzin active ingredient.
• The choice of solvent significantly impacts the accuracy of GLC analysis for metribuzin.
• Methylene chloride offers a reliable and precise solvent for metribuzin quantification via GLC.