Development of a method for the analysis of hormones and pharmaceuticals in earthworms by quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Abstract

The earthworm represents a kind of creature in contact with the soil surface and usually exposed to a variety of organic pollutants from human activities. Therefore, it can be considered as an organism of choice for identifying pollution or better understanding the input of contaminants in food chains in particular through the contributions of sludge. Moreover, the use of organisms such as soil invertebrates is to be developed for ecotoxicological risk assessment of pollutants. In this context, a simple, rapid and effective multi-residue method was developed for the determination of 31 compounds including 11 steroids, 14 veterinary antibiotics and 6 human contaminants (paracetamol, sulfamethoxazole, fluvoxamine, carbamazepine, ibuprofen, bisphenol A) in earthworm. The sample preparation procedure was based on a salting-out extraction with acetonitrile (QuEChERS approach) that was optimised with regard to the acetonitrile/water ratio used in the extraction step, the choice of the clean-up and the quantity of the matrix. The optimised extraction method exhibited recoveries that comprised between 44 and 98 % for all the tested compounds. The limits of detection of all compounds were below 14 ng g⁻¹ and the limits of quantification (LOQ) comprised between 1.6 and 40 ng g⁻¹ (wet weight). The method was therefore applied to determine the levels of pharmaceuticals and hormones in six earthworm samples collected in various soils. Concentrations up to 195 ng g⁻¹ for bisphenol A were determined, between a few nanograms per gram and 43.1 ng g⁻¹ (estriol) for hormones and between a few nanograms per gram and 73.5 ng g⁻¹ (florfenicol) for pharmaceuticals. Experiments were also conducted in laboratory conditions to evaluate the accumulation of the target substances by earthworm.