Determination of five bisphenols in commercial milk samples by liquid chromatography coupled to fluorescence detection

Cytotoxicity of seven bisphenol analogues compared to bisphenol A and relationships with membrane affinity data

Bisphenol A (BPA) is a chemical used in numerous industrial applications. Due to its well ascertained toxicity as endocrine disruptor, industries have started to replace it with other bisphenols whose alleged greater safety is scarcely supported by literature studies. In this study, the toxicity of seven BPA analogues was evaluated using both in silico and in vitro techniques, as compared to BPA toxicity. Furthermore, their affinity indexes for phospholipids (i.e. phospholipophilicity) were determined by immobilized artificial membrane liquid chromatography (IAM-LC) and possible relationships with in vitro toxic activity were also investigated. The results on four different cell cultures yielded similar ranking of toxicity for the bisphenols considered, with IC₅₀ values confirming their poor acute toxicity. As compared to BPA, bisphenol AF, bisphenol B, bisphenol M, and bisphenol A diglycidyl ether resulted more toxic, while bisphenol S, bisphenol F and bisphenol E were found as the less toxic congeners. These results are partly consistent with the scale of phospholipid affinity showing that toxicity increases at increasing membrane affinity. Therefore, phospholipophilicity determination can be assumed as a useful preliminary tool to select less toxic congeners to surrogate BPA in industrial applications.

Development of an immunoaffinity column for the highly sensitive analysis of bisphenol A in 14 kinds of foodstuffs using ultra-high-performance liquid chromatography tandem mass spectrometry

An immunoaffinity clean-up material based on a monoclonal antibody (mAb) has been prepared for concentrating and purifying bisphenol A (BPA) in 14 kinds of foodstuffs at trace level. Haptens and immunogen of bisphenol A have been synthesized and comprehensively characterized. An mAb towards BPA was prepared and cross-reactivities with 14 BPA analogues were below 5%. The prepared antibody was coupled to N-hydroxysuccinimide-activated Sepharose 4B to manufacture an immunoaffinity column (IAC), which was applied to purify BPA in 14 kinds of foodstuffs. The analyte was then detected by means of ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Under the optimized conditions, compared with two traditional SPE clean-up methods, the IAC showed better selectivity (matrix effect <16.8%) and higher sensitivity. The limits of detection for BPA in 14 kinds of foodstuffs ranged from 0.001 μg L^-1 to 0.01 μg kg^-1, and the limits of quantification were in the range from 0.003 μg L^-1 to 0.04 μg kg^-1. The recoveries of BPA from spiked samples ranged from 82.0% to 104.9%, with RSDs below 13.8%. Besides, the IAC exhibited good reusability, with 40% column capacity remaining and no significant loss of recovery after 25 application cycles in real sample detection. These results demonstrated that the developed IAC-UPLC-MS/MS approach has wide applicability for purifying and detecting BPA in various foodstuffs.

Bisphenol A and Bisphenol S release in milk under household conditions from baby bottles marketed in Italy

A simple and sensitive validated analytical method based on liquid chromatography coupled to tandem fluorescence (FD) and ultraviolet (UV) spectrophotometry was applied to monitor the presence of bisphenol A and bisphenol S in plastic baby bottles marketed in Italy. The limits of detection (LOD) were 3.75 ng mL^-1 and 80.00 ng mL^-1, and those of quantification (LOQ) were 12.51 ng mL^-1 and 260.00 ng mL^-1 for BPA (FD detection) and for BPS (UV detection), respectively. BPA was found in only four samples, two samples undergone to microwave heating and two samples undergone to bottle warmer heating either at 40°C or at 80°C. Although the quantities of leached BPA were well below the reference dose for daily intake established by the European Food Safety Authority (EFSA) (4.0 µg kg^-1 bw/day), the release of BPA and BPS from these plastic materials should be carefully considered by the government authorities to increase people's awareness on this issue and to protect the most vulnerable population group.

Modification of Lipid Profile in Commercial Cow Milk Samples before and after Their Expiration Date: Evaluation of Storage Crucial Parameters and Possible Environmentally Friendly Disposal Alternatives

Milk waste is considered a highly polluting material and its disposal is an economic and environmental problem for the dairy sector. Despite this, it can be turned into a source of nutraceutical products and biodiesel substrate. The objective of this study was to determine the qualitative and quantitative variation of single fatty acids in cow milk samples before expiration date and within 28 days after expiration date in order to monitor how the profile of the lipid fraction is influenced by different physicochemical parameters. It was shown that lipolysis in milk is a process independent of time but dependent on the values of pH and total titratable acidity, while crucial parameters for the lipid oxidation are temperature and time of exposure to atmospheric oxygen. All of these factors are at the basis of the efficacy of milk storage conditions. Moreover, our data demonstrate that milk, several weeks after its expiry date, is a rich source of fatty acids that may be recovered as potential substrates for the formulation of economically viable products and eco-friendly diesel-like fuels.

Monitoring of bisphenol A and bisphenol S in thermal paper receipts from the Italian market and estimated transdermal human intake: A pilot study

Bisphenol A (BPA), a synthetic xenoestrogen widely used in various industrial fields, can be present, in its un-reacted form, as an additive in thermal paper. BPA is virtually ubiquitous in industrialized societies and humans are exposed to this chemical via dietary and non-dietary sources. Since in 2015 European Food Safety Authority (EFSA) indicated that thermal paper is the second source of BPA exposure after the food chain, some suppliers replaced BPA with its analogue Bisphenol S (BPS), speculatively supposed to be safer. In this work BPA and BPS concentration levels were determined in thermal paper receipts collected in Italy from 50 different sources by liquid chromatography coupled to tandem fluorescence and ultraviolet detection. BPA was found in 44 samples at mean concentration of 107.47μg/100mg of paper (from below Limits of Quantification (LOQ) to 1533.733μg/100mg of paper). BPS was found in 31 samples at mean concentration of 41.97μg/100mg of paper (from below the LOQ to 357.989μg/100mg of paper). 26 samples were positive to both BPA and BPS. The estimate daily intake (EDI) values of BPA and BPS occurring through dermal absorption were calculated for 70kg body weight individuals. For general population, they were 0.0625μg/day for BPA and 0.0244μg/day for BPS, based on the mean content of bisphenols found. For occupationally exposed individuals, they were 66.8μg/day for BPA and 15.6μg/day for BPS, based on the worst scenario. Such levels would produce a dermal intake below the Tolerable Day Intake established by EFSA (4μg/kg·bw/day); nevertheless, the occurrence of co-exposure to dietary and non-dietary sources should be considered in the health risk assessment, mainly for people frequently exposed to thermal paper contact for occupational reason.

Application of a novel mass spectrometric (MS) method to examine exposure to Bisphenol-A and common substitutes in a maternal fetal cohort

The use of Bisphenol A (BPA) has widely been replaced in consumer products by analogs BPB, BPE, BPF, BPS, and BPAF. Recent studies have linked these substitutes to similar adverse health outcomes as BPA, including disruption of endocrine pathways in animal and human studies. We designed a novel MS method, developed specifically for this study, to capture the most relevant BPA alternatives, BPB, BPE, BPF, BPS, BPAF and 4-NP in human blood and urine to quantify potential in utero exposures. To our knowledge, this is the first study to explore in utero exposure to these BPA analogs and the first U.S. study to test for BPA in maternal/fetal pairs. The method was run on 30 paired maternal urine and fetal cord blood samples from mothers undergoing elective Caesarean sections. 90% of mothers and 77% of babies tested positive for at least one BP analog. 83% of mothers tested positive for BPAF, 60% for BPS, 57% for BPB, 17% for BPF and 7% for BPA. 57% of babies tested positive for BPAF and 50% for BPF. BPA and BPB were detected in one cord blood sample each. BPS was not detected in cord blood. BPE was not detected in any fetal cord blood or maternal urine samples. These findings demonstrate the pervasiveness of some BP analogs in pregnant women and their babies at birth.

Application of the yeast-based reporter gene bioassay for the assessment of estrogenic activity in cow's milk from Poland

Milk contain compounds acting through the estrogen receptor signaling. The still open question whether such estrogens pose a risk for human health, encouraged us to measure the overall estrogenic activity of cow's milk in the in vitro yeast reporter bioassay. First, we assessed the ability of the bioassay to detect estrogens frequently detected in milk. The relative potencies of 16 compounds descended in the order: 17β-estradiol (17β-E2), 17α-ethinylestradiol, diethylstilbestrol, dienestrol, 17α-E2, estrone, zearalenone, estriol, equol, genistein, 17β-E2 glucuronide, bisphenol A, apigenin, daidzein. Flavone, 4-n-nonylphenol and 4-t-octylphenol shown no activity in the bioassay.The estrogenic activities of milk samples without hydrolysis were below the detection limit, whereas in 50% of the deconjugated samples they varied between 0.29 and 0.49 ng EEQ mL(-1). We also compared the estrogenic activity in raw cow's milk collected from rural and industrial locations in Poland. In our pilot study we did not observe statistically significant difference in estrogenic activities in milk collected from the two locations. We found that the daily intake of estrogens with milk may be higher than estrogen levels in human serum. Further studies are warranted to evaluate the significance of milk and dairy as a source of estrogens for humans.