Developing a Rapid, Routine Method for Extraction and Quantification in Complex Infant Products with UPLC/MS-MS

Bisphenol A (BPA) is an additive that is primarily used in the production of polycarbonate plastics and epoxy resins. These synthetic materials are widely used in packaging to protect the safety and integrity of foods and beverages.

Polycarbonates are used to produce many food and beverage containers, such as beverage bottles, tableware, and other food containers. Epoxy resin coatings prevent corrosion of metal cans and lids, along with contamination of food and beverages.

BPA is an endocrine disruptor that can mimic the body’s hormones and may lead to negative health effects. In 2001, concerns about the estrogenic activity of BPA were raised, prompting several governments to release reports questioning the safety of its use in consumer products.

Canada became the first country to take action on BPA through their Chemicals Management Plan, which lists BPA as a toxic substance. The United States Food and Drug Administration (U.S. FDA) released a report in 2010 expressing some concerns regarding BPA exposure to fetuses, infants, and young children that has encouraged further studies into the safety of BPA. A European Union directive (EU directive 2011/8/EU) has also banned the use of BPA in the manufacture of infant feeding bottles.

Related:

• Baby teether study finds many contain potentially harmful chemicals
• Migration of Parabens, Bisphenols, Benzophenone-Type UV Filters, Triclosan, and Triclocarban from Teethers and Its Implications for Infant Exposure

The Analytical Solution

Here we demonstrate how to use UPLC and mass spectrometry in a rapid, routine analytical method for the extraction and quantification of bisphenol A in infant products. Low levels of quantification can be achieved while simultaneously minimizing any potential matrix interference from the complex samples.

Infant formula and baby food were subjected to a short and rigorous extraction protocol prior to analysis. The samples were first extracted with the Waters DisQuE dispersive sample preparation product, that uses the widely accepted QuEChERS protocol. The first tube containing sodium citrate, sodium chloride, and magnesium sulphate was mixed with the 10 g sample and 10 mL of acetonitrile. The supernatant was thoroughly mixed then centrifuged to a 5:1 enrichment, and further cleaned using solid phase extraction (SPE) with Oasis HLB Cartridges.

The final organic eluate following SPE was diluted 50:50 with water, filtered, and injected for LC/MS/MS. This avoided the time-consuming evaporation and reconstitution steps often associated with SPE.

The filtered extracts were analyzed using a high pH, methanol gradient on a 1.7 µm ACQUITY UPLC BEH C18 Analytical Column. The analysis was performed with a Xevo TQD in negative ion electrospray (ESI) mode using multiple reaction monitoring (MRM). A deuterated BPA D16 internal standard was used to correct for variations in both extraction and ionization efficiencies.

Resulting MRM chromatograms of the quantification ion for a 1 µg/kg (1 ppb) spike in infant formula and baby food are shown in Figure 1 (download pdf). A calibration from 0.5 to 50.0 µg/kg demonstrated good linearity, as shown in Figure 2, below, and recoveries were in the range of 95% to 110%.

Summary

The ACQUITY UPLC System coupled with the Xevo TQD mass spectrometer enables the low-level detection of bisphenol A from baby food and infant formula. The use of an additional SPE cleanup step following the QuEChERS extraction protocol ensures that low levels of quantification were achieved through pre-concentration and simultaneously minimized any potential matrix interference from the complex samples.

Avoiding the time-consuming evaporation and reconstitution steps of the standard SPE protocol increased the sample throughput.

In combination with the rapid, sensitive, and selective analysis afforded by UPLC/MS/MS, laboratory efficiency can be maximized.

Additional Resources:

• Download the technology brief for additional data: Rapid Analysis of Bisphenol A in Infant Products Using the Xevo TQD
• QuEChERS Sample Preparation for UPLC/MS/MS Determination of Bisphenol A in Infant Formula
• Rapid Analysis of Bisphenols A, B, and E in Baby Food and Infant Formula Using ACQUITY UPLC with the Xevo TQD
• Chemical Analysis of Food Packaging Migrants and Other Chemical Contaminants in Infant Formula Using a TOF-Based Approach
• Waters’ solutions for analyzing extractables and leachables, including our applications notebook