牛乳中掺碱残留钠离子检测的研究

采用电感耦合等离子发射光谱法(ICP-AES)对鲜牛乳中掺食用碱(Na2CO3)、小苏打(NaHCO3)后残留钠离子检测方法进行了研究。样品前处理采用微波消解和电热板湿法消解两种方法。优化了仪器条件、考察了基体干扰,确定钠离子谱线为589.592nm,进行了定量分析研究。该方法线性范围为0.0μg/mL～20μg/mL,回归方程为ρ(钠)=76.428 6 D(λ)+0.854 9,r=0.999 9,样品前处理采用微波消解方法定量限为14mg/kg,样品前处理采用电热板湿法消解方法定量限为57 mg/kg,回收率达85%以上,RSD<5.0%,准确度高,精密度好。通过大量实验,摸索出牛乳中钠含量大于750mg/kg时,涉嫌人为掺碱。

Research of sodium ion residues in milk mixed with dietary alkali

In this paper,test method of sodium ion residues in fresh milk mixed with dietary alkali（Na2CO3） and saleratus（NaHCO3）was studied with inductively coupled plasma-atomic emission spectroscopy（ICP-AES）.Sample preparation methods of both microwave digestion and wet digestion were used,Instrumentation Conditions were optimized,matrix interference was inspected,spectrum line of sodium 589.592 nm was determined,quantitative analysis was studied.The linear range is 0.0 μg /mL ～ 20 μg /mL,regression equation is ρ（钠）= 76.428 6 D（λ）＋0.854 9,r = 0.999 9,limit of quantification is 16 mg /kg,recovery rate is more than 85%,RSD is less than 5.0%.The method is high accuracy and good precision.Trough large number of experiments,we came to the conclusion that the behavior of artificially added alkali in milk will be suspected When sodium contents determined were more than 750 mg /kg.