研究了以纳米Fe3O4为固相吸附剂对痕量无机砷形态的吸附与分离富集,建立了无需洗脱分离的悬浮进样-氢化物发生-原子荧光法测定砷形态的方法。选择的反应体系为0.64 g/L Fe3O4悬浮液-1.0%(m/V)NaBH4溶液-5.0%(V/V)HCl(pH 8),进样5.0 mL时,得到本方法的检出限为13.5 ng/L;As(Ⅲ)浓度在0.05～3.5μg/L范围内呈良好的线性关系;测定0.5μg/L As(Ⅲ)的精密度RSD=3.4%。用国家标准物质GBW10010(大米)验证了本方法测定砷的准确性,测定结果(0.101±0.010μg/g)与标准值(0.102±0.008μg/g)吻合。采用本方法测定了近海海水和雪水样品中的无机砷形态,并进行了加标回收实验。对As(Ⅲ)和As(Ⅴ)的加标回收率在95%～110%之间,结果令人满意。 The adsorption and separation and enrichment of trace inorganic arsenic species with nano-Fe3O4 as solid phase adsorbent were studied. A method for the determination of arsenic species by suspension injection-hydride generation-atomic fluorescence without elution and separation was established. The reaction system was selected as 0.64 g / L Fe3O4 suspension -1.0% (m / V) NaBH4 solution -5.0% (V / V) HCl (pH 8) 13.5 ng / L. As (Ⅲ) concentration was in the range of 0.05-3.5 μg / L. The RSD of 0.5 μg / L As (Ⅲ) was 3.4%. The accuracy of this method for the determination of arsenic was verified by the national standard GBW10010 (rice). The measured results (0.101 ± 0.010μg / g) were in good agreement with the standard values ​​(0.102 ± 0.008μg / g). The inorganic arsenic speciation in offshore seawater and snow water samples was determined by this method and spiked recovery experiments were carried out. The recoveries of As (Ⅲ) and As (Ⅴ) were between 95% and 110% with satisfactory results.