Solvents - Determination of water in solvents

Importance of the Topic

Determining trace amounts of water in organic solvents is crucial for quality control and process reliability in chemical, pharmaceutical, and materials research applications.

Objectives and Study Overview

This study demonstrates a rapid gas chromatographic method for quantifying water in nine common solvents using an Agilent CP-Wax 52 CB column, achieving complete separation in under seven minutes.

Methodology

The procedure employs capillary gas chromatography with hydrogen as the carrier gas at 90 kPa. A 0.5 µL sample injection (1:100 split) is performed at 150 °C, and water content is measured over a concentration range around 0.5% v/v.

Used Instrumentation

• GC system equipped with Thermal Conductivity Detector (TCD) at 150 °C
• Agilent CP-Wax 52 CB fused-silica WCOT column (0.32 mm × 25 m, film thickness 1.2 µm)
• Hydrogen carrier gas at 0.9 bar
• Split injector (1:100) operating at 150 °C

Main Results and Discussion

The method achieved baseline separation of water from solvent peaks (including acetone, dichloromethane, methanol, ethanol, ethyl acetate, isopropyl ether, tetrahydrofuran, dioxane, and methyl propyl ketone) within seven minutes. Retention times were reproducible, and the technique displayed good sensitivity around 0.5% v/v water.

Benefits and Practical Applications

This approach offers rapid turnaround and reliable quantification of water impurities in solvents, supporting routine quality assurance in manufacturing, materials testing, and regulatory compliance.

Future Trends and Opportunities

Advances may include coupling with mass spectrometry for enhanced selectivity, miniaturized columns for faster analysis, and integration into automated online monitoring systems for continuous process control.

Conclusion

The described GC-TCD method on a CP-Wax 52 CB column provides a fast, robust, and accurate solution for water determination in a variety of organic solvents, meeting industrial demands for high throughput and precise moisture analysis.