催化光度法测定卷烟中的痕量镍

Determination of Trace Nickel in Cigarette by Catalytic Kinetic Spectrophotometry

摘要: 根据在醋酸-醋酸钠缓冲介质中,痕量镍离子对过氧化氢氧化丁基罗丹明B(BRB)褪色反应有催化作用原理,建立了测定卷烟中痕量镍的催化光度法。即将烟丝样品消化液与2.5 mL pH5.0的醋酸-醋酸钠缓冲溶液、2.0 mL 2% Triton X-100溶液、3.5 mL 3%过氧化氢溶液和3.0 mL 0.01% BRB溶液,在75℃水浴中反应8 min,于560 nm波长下检测其吸光度。在0.32~12.0μg/L线性浓度范围内,方法检出限为0.078μg/L,RSD为2.2%~4.2%,回收率为97.3%~102.7%。该法的测定结果与原子吸收光谱法的吻合。

Abstract: A method for determining trace nickel in cigarette by catalytic kinetic spectrophotometry was developed based on that Ni(Ⅱ) has a catalytic effect on the oxidative discoloration of butylrhodamine-B(BRB) with hydrogen peroxide in HAc-NaAc buffer solution.2.0 mL digested tobacco solution was reacted with 2.0 mL 2% Triton X-100,3.5 mL 3% hydrogen peroxide,and 3.0 mL 0.01% BRB in the presence of 2.5 mL pH5.0 HAc-NaAc buffer solution for 8 minutes in a water bath at 75℃ and then detected at the wavelength of 560 nm.The recovery of Ni(Ⅱ) was from 97.3% to 102.7% with RSD of 2.2% to 4.2%,the limit of detection of 0.078 μg/L in the linear concentration range of 0.32 to 12.0 μg/L.The Ni(Ⅱ) content in tobacco determined with this method agreed with the results of atomic absorption spectrophotometry.