ASTM D5507 Trace Organic Impurities in Monomer Grade Vinyl Chloride

Scope:

ASTM D5507 is a capillary-based general-purpose test method for determining trace contaminants in high-purity vinyl chloride. This test technique incorporates serially connected capillary PLOT columns with multidimensional column switching and cryogenic trapping techniques that can provide complete separation of the 11 main vinyl chloride contaminants in a  single 25-minute run. This test’s multidimensional technique allows all trace contaminants to be well isolated from the primary vinyl chloride peak, resulting in better quantitative accuracy than traditional packed column procedures.

Procedure:

For ASTM D5507, the liquid vinyl chloride sample or calibration standard is injected either directly or as an expanding gas through a high-pressure liquid sampling valve. To reach the desired detection limits, an adequate volume of liquid or gas sample is injected. On a 6-m pre-column, a preliminary GC separation is performed to separate the majority of the vinyl chloride peak from the trace peaks of interest. This pre-column separation yields two heart-cut transfers,  which send selected pieces to a second column for further separation. Ten of the eleven trace impurities of interest are present in these two cuts, but not 1,2 ethylene dichloride or the majority of the vinyl chloride peak. The 1,2 EDC peak is eluted from the 6-m pre-column and detected at the first FID after the two cuts.

Then, by comparing the retention durations and area counts acquired from a calibration standard operated under similar conditions, the components that elute to the two FID detectors are identified and measured.

Specimen size:

Vinyl chloride in its liquid form is used as a test specimen for the ASTM D5507 test procedure. 

Result:

In ASTM D5507, the concentrations of each of the components of interest are calculated using the following equation:

Qx = (A_x)(Q_es) / (A_es)

where,

Q_x = concentration of the components in the vinyl chloride sample

Q_es = concentration of the component in the calibration standard

A_x= integrated-area count for the component from the sample run

A_es = integrated-area count for the component from the standard run

Conclusion:

ASTM D5507 is a capillary-based general-purpose test method for determining trace contaminants in high-purity vinyl chloride.