Scope: 

The ASTM D6143 is a standard test method for the iron content of bisphenol A (4,4’- isopropylidenediphenol). Bisphenol A (BPA) has a lower detection limit of 0.1 mg/kg and a  higher detection limit of 20 mg/kg in this test technique. BPA is also used in the process of manufacturing polycarbonate plastics and epoxy resins as a plasticizer. Specifically, it is used for packaging foods and beverages, baby bottles, thermal papers, and dental sealants.

Test procedure:

For ASTM D6143, bisphenol A is dissolved in methanol before being acidified with hydrochloric acid to convert any ferric iron to ferrous iron. It is necessary to dilute the sample if the iron content is higher. The ferrous iron is subsequently complexed with ferrozine to generate a red/pink chromophore that can be measured at 560 nm using visible spectrophotometry. 

Video 01: Explanation of Bisphenol-A (BPA) and its uses

Specimen size:

For ASTM D6143 test procedure, 5 g of the sample – bisphenol A – is taken to the nearest 0.1 mg into a 100-mL volumetric flask.

Data:

The ppm iron in bisphenol A is calculated as follows: 

absorbance at 560 nm × (D) × (F) 

where: 

D= dilution factor 

F= absorbance factor 

As per the ASTM D6143 test, iron in the bisphenol A is reported to the nearest 0.1 µg/g.

Conclusion:

The ASTM D6143 is a standard test method for the iron content of bisphenol A (4,4’- isopropylidenediphenol).