ASTM D7823 Determination of Low-Level Phthalates in PVC Plastics by Thermal Desorption

Scope:

The ASTM D7823 test method is important to identify and quantify polyvinyl chloride phthalates using thermal desorption, mass spectrometry, and gas chromatography. Different readings are taken along with the determination of the specifications of phthalates. This method is important in imposing standards of use, safety, health, and welfare for different phthalates.  It is also important to separate the phthalates from PVC. This helps in deciding its application and reliability. 

Procedure:

The ASTM D7823 test method requires a gas chromatograph or mass spectrometer to function at a specific temperature ranging from 75 to 350°C. A thermal desorption unit that can endure extreme temperatures is also used. Reusable and disposable containers along with an analytical balance, an integrator, and data handling systems are used. The PVC sample (200 mg) is mixed with 10 mL of tetrahydrofuran (THF). Then a small portion of THF is analyzed through a mass spectrometer, gas chromatograph, and a thermal desorption unit. This helps identify and quantify phthalates through mass spectra. Pressure and gas are regulated through different regulators.

Specimen size:

The sample size for ASTM D7823 is determined as per the requirements. In this case, 200 mg of PVC samples are dissolved in 10 mL of tetrahydrofuran to prepare the sample, and 0.30 mg of the phthalate is dissolved in 10 mL of methylene chloride to prepare a standard solution.

Data:

The quantitative ppm and reproducibility value as RSD % are calculated respectively for different phthalates such as DBP, BBP, DEHP, DNOP, DINP, and DIDP.

Conclusion:

The ASTM D7823 test method is important to identify and quantify polyvinyl chloride phthalates using thermal desorption, mass spectrometry, and gas chromatography.