D3792-16 – Standard Test Method Technical Guide

ASTM D3792 – 16 (Reapproved 2022) establishes a direct injection gas chromatographic (GC) method for determining the total water content in waterborne paints. This test method is a critical tool for calculating Volatile Organic Content (VOC) and has been evaluated for diverse systems including latex (styrene-butadiene, poly(vinylacetate)-acrylic, acrylic), epoxy acrylic resin systems, and pure acrylic systems. The standard formally establishes a working range of 15 % to 90 % water content, while noting that the method may be applicable outside this range. The values stated in SI units are regarded as the standard.

🧪 Summary and Principles of the Test Method

The core procedure requires adding a known amount of an internal standard (such as isopropanol) to a representative aliquot of whole paint. This mixture is then diluted with dimethylformamide (DMF) prior to injection into the gas chromatograph. The GC column, packed with a specific porous polymer material, separates the water peak from other volatile components, allowing for direct, accurate quantification against the internal standard. Reagent water meeting ASTM D1193 Specification for Reagent Water is required for preparing calibration standards.

⚙️ Apparatus and Gas Chromatograph Setup

Any gas-liquid chromatograph equipped with a thermal conductivity detector (TCD) is suitable. Temperature programming capability is preferable to isothermal operation for optimal peak resolution. The specific requirements for the separation column and injection system are detailed below.

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