Speciation analysis, bioavailability and risk assessment of trace metals in herbal decoctions using a combined technique of in Vitro digestion and biomembrane filtration as sample pretreatment method.

Sample preparation is the first crucial step in the speciation analysis, bioavailability and risk assessment of trace metals in plant samples such as herb and vegetables. Two bionic technologies titled 'in vitro digestion' and 'extraction with biomembrane' were developed for pre-treatment of herbal decoction. The decoctions of Aconiteum carmichaeli and Paeonia lactiflora were digested at body temperature, at the acidity of the stomach or intestine and with inorganic and organic materials (digestive enzymes were included for whole-bionic and excluded for semi-bionic) found in the stomach or intestine. Being similar to the biomembrane between the gastrointestinal tract and blood vessels, monolayer liposome was used as a biomembrane model. Affinity-monolayer liposome metals and water-soluble metals were used for speciation analysis and bioavailability assessment of copper and zinc in herbal decoction. In the decoction of Aconiteum carmichaeli and Paeonia lactiflora, Zn was mainly absorbed in the intestine and Cu was mainly absorbed by both stomach and intestine. The safe dosage for males and females is below 257.1 g/day Aconiteum carmichaeli and 529.4 g/day Paeonia lactiflora.