A sensitive, efficient, and reproducible method, based on solid phase extraction and derivatization with acetic anhydride followed by gas chromatography-mass spectrometry in selected-ion monitoring mode, was developed for the determination of bisphenol A (BPA) in liquid infant formula. The method quantification limit was 0.5 ng g(-1). Extraction recoveries were 85-94% over the concentration range of 2.5-20 ng g(-1). Good reproducibility of the method was observed at levels of 0.54 and 10.4 ng g(-1) with relative standard deviations of 5.0 and 2.8%, respectively. The method was used to analyze samples of 21 canned liquid infant formula products for BPA. BPA was detected in all samples at levels ranging from as low as 2.27 ng g(-1) to as high as 10.2 ng g(-1). The probable daily intakes of BPA due to consumption of canned liquid infant formula were estimated for infants from premature to 12-18 months of age. The maximum probable daily intake of BPA was 1.35 microg kg(-1) of body weight day(-1) for 0-1-month-old infants with the maximum formula intake, which is below the provisional tolerable daily intake for BPA established by Health Canada, 25 microg kg(-1) of body weight day(-1).

Lead (Pb), cadmium (Cd) and aluminum (Al) were determined in 437 individual samples of infant formulae, oral electrolytes and 5% glucose solutions available in Canada. In the electrolytes, Cd and Pb concentrations were all below 0.01 and 0.041 ng g−1, respectively. In the 5% glucose solutions, Pb and Cd levels averaged 0.01 and 0.09 ng g−1, respectively. Reported on an as-consumed basis, Pb levels in milk- and soya-based formulae averaged 0.90 and 1.45 ng g−1, respectively, while Cd levels averaged 0.23 and 1.18 ng g−1, respectively Average Al levels on an as-consumed basis were 440 ng g−1 (range 10–3400 ng g−1) in milk-based formulae and 730 ng g−1 (range 230–1100 ng g−1) in soy-based formulae. Al concentrations increased in the following order: plain formula < low-iron formula < iron-supplemented formula < casein hydrolysate formula ≈ premature formula ≤ soy formula. For example, in the powdered formulae, average Al concentrations were 18 ng g−1 for plain milk-based, 37 ng g−1 for low-iron, 128 ng g−1 for iron supplemented, 462 ng g−1 for lactose-free, 518 ng g−1 for hypoallergenic and 619 ng g−1 for soy-based formula. Al concentrations, as-consumed, increased with decreasing levels of concentration: powder < concentrated liquid < ready-to-use. Formulae stored in glass bottles contained between 100 and 300 ng g−1 more Al than the same formulae stored in cans. The source of the increased Al did not appear to be the glass itself, because most electrolytes and glucose solutions, also stored in glass, contained less than 8 ng g−1 Al. Corresponding differences in Pb and Cd levels were not observed. Al concentrations varied substantially among manufacturers; however, all manufacturers were able to produce plain milk-based formulae containing less than 50 ng g−1 Al, i.e. within the range of Al concentrations found in human milk. Next to soya-based and hypoallergenic formulae, premature formulae contained among the highest concentrations of Al, ranging 851–909 ng g−1 from one manufacturer and 365–461 ng g−1 from another.

A method based on solid-phase extraction followed by HPLC analysis with fluorescence detection was developed for the determination of bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE) in liquid infant formula. In this method, instead of trying to isolate and measure each individual form of the molecules, hydrolysis of BADGE, BFDGE, BADGEH2O, and BFDGEH2O was forced to completion to their stable forms, BADGE2H2O and BFDGE2H2O, before extraction. The method LODs were 2.0 ng/g for BADGE and 3.0 ng/g for BFDGE. Extraction recoveries were 6191 for BADGE, and 5582 for BFDGE over the concentration range of 10 to 50 ng/g. The method was used to analyze samples of 21 canned liquid infant formula products for BADGE and BFDGE. BADGE was detected in samples of all products at levels ranging from as low as 2.4 ng/g to as high as 262 ng/g. BFDGE was detected in only one product (40 ng/g), and this product also had the highest BADGE level (262 ng/g). HPLC/MS/MS with a similar LOD was also used to confirm the results. The probable daily intakes (PDI) of BADGE and BFDGE due to consumption of canned liquid infant formula were estimated for infants from premature to 1218 months of age. The maximum PDI of BADGE was 22 g/kg body weight/day for the 1218 months old with the maximum formula intake. The maximum PDI of BFDGE was &lt;3.4 g/kg body weight/day.

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