In vitro study of thimerosal reactions in human whole blood and plasma surrogate samples

Because of its bactericidal and fungicidal properties, thimerosal is used as a preservative in drugs and vaccines and is thus deliberately injected into the human body. In aqueous environment, it decomposes into thiosalicylic acid and the ethylmercury cation. This organomercury fragment is a potent neurotoxin and is suspected to have similar toxicity and bioavailability like the methylmercury cation. In this work, human whole blood and physiological simulation solutions were incubated with thimerosal to investigate its behaviour and binding partners in the blood stream. Inductively coupled plasma with optical emission spectrometry (ICP-OES) was used for total mercury determination in different blood fractions, while liquid chromatography (LC) coupled to electrospray ionisation time-of-flight (ESI-TOF) and inductively coupled plasma-mass spectrometry (ICP-MS) provided information on the individual mercury species in plasma surrogate samples. Analogous behaviour of methylmercury and ethylmercury species in human blood was shown and an ethylmercury-glutathione adduct was identified.