藏药佐太中单质硫对β-HgS中汞溶出的影响

Effect of sulfur on Hg dissolution ofβ-HgS in Tibetan medicine Zuotai

【目的】研究单质硫对β-HgS在胃肠道条件下汞溶出的影响及机制.【方法】模拟佐太中β-HgS和单质硫的组成,采用体外溶出试验方法,测定β-HgS、β-HgS与单质硫混合物在含或不含L-半胱氨酸的模拟胃、肠液及不同pH条件下溶出的汞浓度,测定β-HgS在不同浓度Na2S,Na2SO3或Na2S2O3的含L-半胱氨酸的模拟肠液中溶出的汞浓度.【结果】单质硫对β-HgS中汞溶出的影响及其与pH、L-半胱氨酸关系的试验表明,单质硫可抑制β-HgS在不含L-半胱氨酸的模拟肠液和含L-半胱氨酸的模拟胃、肠液中汞的溶出;该抑制作用与溶液pH条件有关,与溶液中是否含有L-半胱氨酸关系较小.硫离子形态对β-HgS在含L-半胱氨酸的模拟肠液中汞溶出影响的试验表明,Na2S和Na2S2O3分别在5~50、1000 mg/L下抑制β-HgS中汞溶出的作用与单质硫的抑制作用相似.【结论】单质硫是造成β-HgS在不含L-半胱氨酸的模拟肠液和含L-半胱氨酸的模拟胃、肠液中溶出的汞浓度显著降低的主要因素;单质硫主要通过生成S2-来抑制β-HgS在含L-半胱氨酸的模拟肠液中的汞溶出.

【Objective】To investigate the effect and mechanism of elemental sulfur on Hg dissolution ofβ-HgS under the condition of gastrointestinal tract.【Method】The composition ofβ-HgS and elemental sulfur in Zuotai was simulated and the in-vitro-dissolution test was used to measure the concentration of dissolved Hg fromβ-HgS or the mixture ofβ-HgS and elemental sulfur in simulated gastric and intestinal fluids under different pH values with or without L-cysteine.And the concentration of dissolved Hg fromβ-HgS was measured in L-cysteine-containing simulated intestinal fluid at different concentrations of Na2S,Na2SO3 or Na2S2O3.【Result】The effect of elemental sulfur on Hg dissolution ofβ-HgS and its relationship with pH and L-cysteine showed that elemental sulfur inhibited Hg dissolution ofβ-HgS in L-cysteine-free simulated intestinal fluid and L-cysteine-containing simulated gastric juice and intestinal fluids.And this inhibition effect was related to the pH value of solutions,but less related to L-cysteine.The effect of sulfide ion morphology on Hg dissolution ofβ-HgS in L-cysteine-containing simulated intestinal fluid showed that Na2S and Na2S2O3 respectively inhibited the Hg dissolution at 5~50 and 1000 mg/L,which were similar to elemental sulfur.【Conclusion】Elemental sulfur was the main factor significantly reducing the concentration of dissolved Hg ofβ-HgS in L-cysteine-free simulated intestinal fluid and L-cysteine-containing simulated gastric juice and intestinal fluids.Elemental sulfur inhibited the Hg dissolution ofβ-HgS in L-cysteine-containing simulated intestinal fluid mainly by producing S2-.