(Au)_核(Ag)_壳纳米微粒-火焰原子吸收光谱法测定过氧化氢

在90 ℃水浴条件下，以粒径为10 nm的纳米金做晶种，用柠檬酸三钠还原硝酸银，制备了平均粒径为30 nm的（Au）核（Ag）壳纳米微粒，用高速离心纯化除去过量的柠檬酸三钠获得了较纯的（Au）核（Ag）壳纳米微粒。在pH 3.8的HAc-NaAc缓冲溶液中，Fe2＋催化H2O2反应产生的羟基自由基可氧化（Au）核（Ag）壳纳米微粒生成银离子。离心后，离心液中的银离子可用火焰原子吸收光谱法在328.1 nm波长处测量。随着H2O2浓度增大，离心液中银离子浓度增加，其吸光度值增加。H2O2浓度在2.64～42.24 μmol·L-1范围内与上清液中银离子的原子吸收值ΔA呈良好的线性关系，回归方程为ΔA=0.014c-0.013 1, 相关系数为0.998 4，检出限为0.81 μmol·L-1 H2O2。当用于水样中H2O2的测定，获得了满意的结果。

Flame Atomic Absorption Spectrometric Determination of H_2O_2 Using(Au)_(core)(Ag)_(shell )Nanoparticles

The 10 nm gold nanoparticles were prepared by Frens procedure. Using tri-sodium citrate as reducer of AgNO3, and 10 nm gold nanoparticles as seed, the (Au)core(Ag)shell nanoparticles the size of about 30 nm were prepared at 90 ℃ for 10 min. Then it was separated by centrifuge at 10000 r·min-1 for 15 min to obtain pure (Au)core(Ag)shell nanoparticles. In pH 3.8 sodium acetate-acetic acid buffer solution, hydroxyl free radical from Fenton reaction between Fe(Ⅱ)-H2O2 oxidized (Au)core(Ag)shell nanoparticles to form silver ions. The silver ions in the centrifugal solutions can be measured by flame atomic absorption spectrometry at 328.1 nm. The silver ions in the centrifugal solutions increased with the H2O2 concentration increasing, and the absorption value at 328.1 nm was enhanced linearly. The influence factors such as pH value, buffer solution volume, concentration of (Au)core(Ag)shell and Fe(Ⅱ), reaction temperature and time, and centrifuging velocity and time were considered, respectively. Under the conditions of 0.20 mL pH 3.8 sodium acetate-acetic acid buffer solution, 50 μL of 2.0 mmol·L-1 FeSO4, 60 μL of 2.94×10-4 mol·L-1 (Au)core(Ag)shell nanoparticle solution, reaction time of 20 min at 60 ℃, and centrifugalization at 14 000 rpm for 10 min, the increased value ΔA is proportional to the H2O2 concentration (ｃ) from 2.64 to 42.24 μmol·L-1, with a detection limit of 0.81 μmol·L-1. The regress equation was ΔA=0.014ｃ-0.013 1, with a coefficient of 0.998 4. The effect of foreign substances such as 100-times glucose, Cu2+, Mg2＋, Ca2+，50-times urea, bovine serum albumin, Mn2+, Pb2+, and 30-times Cr3+ on the determination of 13.2 μmol·L-1 H2O2 was examined respectively, with a relative error of ±10％. Results showed that there was no interference. This assay showed high sensitivity and good selectivity for quantitative determination of H2O2 in waste water samples, with satisfactory results. The analytical results were in agreement with that of the reference results.