Application of the GC-MS method in combination with preliminary solid phase extraction on a magnetic molecular imprinted polymer for the determination of bisphenol A in soils of various types

A method of gas chromatography-mass spectrometry (GC-MS) in combination with pre-concentration on a sorbent with BPA molecular imprints (dosage of sorbent — 50 mg, sorption time — 10 min, pH — 3, desorption with methanol) is used to determine bisphenol A (BPA). The sorbent extracts about 96% of BPA from aqueous solutions with a single sorption and is characterized by a high imprinting factor reaching 7.1. The samples of soils of urbanized territories, as well as typical chernozems and residual carbonate chernozems outside the large cities of the Voronezh region were studied. The limit of BPA detection was 0.07 μg/kg (in terms of dry soil), the range of the linearity of the calibration graph was 0.3 – 35 μg/kg. Determination of bisphenol is hindered by soil contamination with petroleum products, which can be eliminated by washing with heptane. It has been revealed that pH of soils has a significant effect on the BPA migration of along the soil profile. The concentration curves of the BPA distribution over the soil profile up to a depth of 1 m were plotted. The maximum BPA concentrations in the soils of urbanized territories depend on the contamination of the territory with polymer waste. The maximum BPA concentrations (29.84 μg/kg) were determined at a depth of 20 cm in samples taken near the landfill of municipal solid waste. At other points within the city limits, the maximum concentrations range within 5.38 – 8.77 μg/kg. Outside the city of Voronezh, the mobility of BPA increases in more alkaline typical and residual-calcareous chernozems and significant concentrations of the pollutant were found at a depth of 50 – 80 cm. The developed scheme can be applied to targeted screening and monitoring of the BPA content. The method can be used for BPA determination in soil horizons for various soil types, meteorological conditions (precipitation, annual temperature regime), and contamination of the territory (the presence of unauthorized landfills, MSW landfills, sewage treatment facilities near the sampling point).