Bisphenol A (BPA) Analysis in Water Using UCT ENVIRO-CLEAN SPE C18 Extraction Cartridges with LC–MS-MS Detection

The analysis of Bisphenol A using UCT Enviro-Clean® C18 cartridges and UCT Selectra® Phenyl columns using LC–MS-MS is discussed.

Bisphenol A, (4, 4'-dihydroxy-2,2'-diphenylpropane), is a difunctional phenolic monomer used for the production of epoxy resins and polycarbonates. The safety of this monomer has been a subject of question. Recently, BPA has come under scrutiny as the compound is detected in various surface waters, canned foods, and other sources and is believed to be an endocrine disruptor hormone (1–2).

A characteristic of Bisphenol A is that it readily partitions from various aqueous and food media using C18 SPE. This note describes a robust SPE sample preparation technique, in reference to this partitioning quality, yielding reproducible, and accurate analysis.

Sample Preparation

To 100 mL of sample water add IS and 100 mM acetic acid to adjust the pH to 7. Bisphenol A has a pKa value of approximately 9.5. The cartridge was conditioned by adding 3 mL of methanol, partially drawing through until the liquid reached the top of the frit. After 1 min, 3 mL of DI water was added to the cartridge followed immediately by 1 mL of 100 mM acetic acid.

Extraction/Elution

The sample was drawn through the cartridge at a rate of approximately 5 mL/min by vacuum, followed by 5 mL DI water wash. The cartridge was dried for 5 min at > 10 inches Hg vacuum. A total of 6 mL of methanol was used to rinse the bottle and cartridge and complete the elution into a collection vial.

Figure 1: Chromatogram of Bisphenol A.

Evaporate

Using a gentle stream of N₂ (< 40 °C) the methanol was evaporated to less than 500 μL before bringing the extract to a final volume of 500 μL with methanol for injection.

Results

The UCT ENVIRO-CLEAN® SPE C18 10 mL Cartridge is effective in capturing BPA from water samples. When spiked at 15.00 ng/mL recovery values of 90–100% were readily obtained. In addition, the use of the UCT Selectra Phenyl HPLC column provided excellent peak shape while minimizing retention and analysis time for rapid analysis.

References

(1) http://medheadlines.com/2009/06/05/fda-chief-agrees-to-reconsider-bpa-safety/

(2) http://www.sciencedaily.com/releases/2009/06/090610124417.htm

We wish to acknowledge the work done by Jeffery Hackett from Northern Tier Research on this Bis-phenol A application note.

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