原子荧光法测定并比较4种金枪鱼背部肉中硒的含量

目的：建立金枪鱼背部肉中硒含量的原子荧光光度测定方法，测定并比较4种金枪鱼背部肉中硒含量。方法：样品加酸经过微波消化后，用硼氢化钠作还原剂，还原成硒化氢（H₂Se），由载气带入原子化器中进行原子化，在硒特制空心阴极灯照射下，基态硒原子被激发至高能态，在去活化回到基态时，发射出特征波长的荧光，其荧光强度与硒含量成正比。选择体系：硒灯电流60 mA；负高压300 V；硼氢化钠浓度1.5%；载气流量400 mL·min^-1；屏蔽气流速600 mL·min^-1。结果：硒的浓度在3.0~30.0 ng·mL^-1之间线性关系良好（r=0.999 7），检出限为0.16 μg·L^-1，回收率在92.6%~101.8%之间。蓝鳍金枪鱼，长鳍金枪鱼，黄鳍金枪鱼和大眼金枪鱼背部肉中硒的含量分别为1.48、0.904、0.909和1.23 mg·kg^-1。结论：该方法能准确检测金枪鱼背部肉中硒的含量，为人们选择富硒食品提供了参考。

Objective: To establish a determination method of selenium contents in tuna back meat by atomic fluorescence spectrometry and compare the selenium contents in four kinds of tuna back meat.Methods: Sample was added with acid and then digested by microwave,hydrogen selenide (H₂Se) was generated by using sodium borohydride as the reducer and was introduced with the carrier into the atomizer for atomization.Ground state selenium atoms were excited to high-energy state under irradiation of a hollow cathode lamp of selenium,and emitted fluorescence at characteristic wavelength when returning to the ground state after deactivation.The fluorescence intensity was positively proportional to the content of selenium.System: lamp current 60 mA; negative pressure 300 V; reducing agent NaBH₄ concentration 1.5%; carrier gas flow rate 400 mL·min^-1; shielding gas flow rate 600 mL·min^-1. Results: Good linearity was presented within the selenium concentration range of 3.0 ng·mL^-1-30.0 ng·mL^-1(r=0.999 7). The detection limit was 0.16 μg·L^-1. Recoveries were within 92.6%-101.8%. The selenium contents of T. thynnus; T. alalunga; T. albacares; T. obesus tuna back meat were 1.48 mg·kg^-1,0.904 mg·kg^-1,0.909 mg·kg^-1,1.23 mg·kg^-1,respectively. Conclusion: The method could accurately determine the selenium content of tuna back meat,which provided a reference for people choosing selenium enriched food.