Determination of vitamin B1 and B2 in infant milk powder by HPLC fluorescencedetector.

Objective To develop a method for the determination of low content vitamin B1 and B2 in infant formula milk powder.Methods 0.5% acetic acid was used as the protein precipitator in infant formula,RP-HPLC,35% methanol and 65% 0.05 mol/L NaAc solution(pH=4.5) was used as the mobile phase,flow rate was 1 ml/min,Zorbax SB-Aq 100% water soluble separate column was used,the temperature was at room temperature,vitamin B1 was determined by fluorescencedetector(λex =375 nm,λem=435 nm),0.25 g/L hexacyanoferrate(Ⅲ)as the post column derivation;vitamin B2 was determined by fluorescencedetector(λex =462 nm,λem=522 nm),vitamin B1 and B2 were analyzed by external calibration method.Results The linear range for vitamin B1 and vitamin B2 were 10-1 000 μg/L,the linear coefficients were 0.999 9,and the detection limits for quantification were 5.1 and 4.7 μg/L,the detection limits for method were 1.5 and 1.4 μg/L,the recoveries were between 86.5%-98.1%,the relative standard deviations were less than 5%.Conclusion This method is simple,rapid,sensitive and is applicable to the fast determination of low content vitamin B1 and B2 in infant formula milk powder.