苹果汁中重金属检测方法研究进展

本研究采用微米级微晶纤维素（microcrystalline cellulose，MCC）和纳米级纤维素纤维（cellulose nanofiber，CNF）为基质，L-赖氨酸为接枝单体，制备了L-赖氨酸功能化纤维素基铅吸附剂，探究吸附剂在果汁中的吸附性能及果汁中糖类与有机酸对吸附性能的影响。结果表明，以单一铅体系为目标溶液，L-赖氨酸功能化高碘酸钠氧化的微晶纤维素（L-lysine functionalized sodium periodate-oxidized MCC，L-g-POCM）与L-赖氨酸功能化四甲基哌啶体系氧化的纳米纤维素纤维（L-lysine functionalized TEMPO-oxidized CNF，L-g-TOCF）对铅（20 mg L⁻¹）有较好的吸附效果，吸附效率分别高达77.36%和96.16%。偏中性的糖类对吸附效果的影响属于较弱的竞争吸附，高酸性的有机酸则属于较强的竞争吸附，且L-g-TOCF受影响程度较小。在pH小于4时，L-g-TOCF的吸附性能被抑制，低至7.54%，而在pH大于4时，最高可达92.18%，因此，L-g-TOCF在低酸类果汁的重金属去除中有良好的前景。

Effects of environmental and occupational lead toxicity and its association with iron metabolism

L-lysine functionalized cellulose-based lead adsorbents were prepared. The microcrystalline cellulose (MCC) and cellulose nanofiber (CNF) were performed as the matrix and L-lysine was used as the grafted monomer. In this study, the adsorption performance of the adsorbents for lead in fruit juice was explored. And the effects of sugars and organic acids on adsorption properties in fruit juice were deeply explored. Both L-lysine functionalized sodium periodate-oxidized-MCC (L-g-POCM) and L-lysine functionalized tetramethylpiperidine system-oxidized-CNF (L-g-TOCF) had excellent adsorption efficiency on lead ions, reaching 77.36% and 96.16%, respectively. The sugar solution was neutral. It had weak competitive adsorption with lead ions. The organic acids with high acidity had strong competitive adsorption with lead ions. Compared with L-g-POCM, L-g-TOCF was less affected. At pH less than 4, the adsorption efficiency of L-g-TOCF was strongly inhibited, as low as 7.54%. When pH greater than 4, it reached up to 92.18%. Thus, L-g-TOCF have a promising prospect of removal heavy metals in low-acid fruit juices.