Study On GC-MS/MS Determination Of Illegal Additive Benzoyl Peroxide In Wheat Flour And Its Dynamic Changes

Wheat flour is the staple in northern of China.There are many kinds of food derived from it,and it is an important food raw material.Benzoyl peroxide(BPO)is a agent that has been commonly added wheat flour bleaching in China since the 1980s.It has the functions of whitening,shortening the ripening time,inhibiting mildew,and increasing the flour extraction rate[1].However,in recent years,studies have found that the unresolved benzoyl peroxide remaining in wheat flour produces benzene free radicals due to heating during food preparation,which in turn will form harmful poisons such as benzene,phenol,and biphenyl,which threaten human health;Benzoic acid,as a reduction product of BPO,will increase the burden on the liver.In severe cases,the liver and kidney will have pathological changes,which will affect growth and lifespan.Since May 2011,our country have banned the use of benzoyl peroxide,but a few foreign countries that still continue to use benzoyl peroxide as a food additive,and there is no uniform standard for the amount of addition.Therefore,the correct determination of benzoyl peroxide in commercially available wheat flour is of great significance.In this study,a fast and simple pre-treatment technology was used in combination with gas chromatography-tandem triple quadrupole mass spectrometry to carry out a qualitative and quantitative study on benzoyl peroxide in wheat flour;due to the instability of benzoyl peroxide,the residual amount and dynamic changes of benzoyl peroxide in wheat flour during storage were also studied based on this method.The main research contents and conclusions are as follows:1.A gas chromatography-tandem triple quadrupole mass spectrometry method was established for the determination of benzoyl peroxide that may be illegally added in wheat flour,and optimized the parameters of the method.The results showed that using 35 mL of acid petroleum ether solution as the extraction solvent,ultrasonic extraction for 60 minutes,using GC-MS/MS to quickly detect the residual amount of benzoyl peroxide in wheat flour.The determination effect is good,and the extraction rate is high.2.Methodological verification of the established method,using a standard working solution with a concentration range of 0.1 ?g/mL?100.0 ?g/mL,BA linear equation(forced to cross the origin):Y=8462.631X+174.7072,linear correlation coefficient is r2>0.999.The limit of detection(LOD)of benzoic acid in this method is 0.5 mg/kg,and the limit of quantification(LOQ)is 1.0 mg/kg.The RSD value of BA is 1.1%,and the accuracy deviation is-8.2%.Under the three spiked levels of 1,10,and 20 mg/kg,the recovery rate of BA is measured in the range from 91.3%to 108.9%,and the recovery effect is satisfactory.3.According to this method,the dynamic change of the residual amount of benzoyl peroxide during the storage of the sample was studied.The 3 samples are divided into 3 concentration levels to study the general tendency of changes in the residual amount of benzoyl peroxide through the addition of the total addition of the standard.The standard addition levels of the blank sample are 20,10,and 5 mg/kg.Under the condition of 30 days later,benzoic acid is determined.The overall reduction rates of residues were 25.36%,16.58%,and 13.43%,respectively.In terms of the additive change of the total amount of spiked samples,the concentration of benzoyl peroxide has a tendency to decrease at each stage.At the addition level of 20mg/kg,the change tendency of general-purpose flour,special flour,and high-gluten flour is consistent with the overall trend.Also,the residual amount keeps decreasing over time.4.The measurement uncertainty of the results of benzoyl peroxide from each step of the measurement method was evaluated,the uncertainty of the identified sources,and analyze the influence of the results,when x<0.43 6(x is the content of benzoyl peroxide),K=2,indicating that the sample test result is undetected within the 95%confidence interval,and the result is reliable.When 0.436<x<0.5,k=2,the measurement result exceeds the detection within the 95%confidence interval.If the limit is limited,re-sampling is required;when 0.5<x<0.564,k=2,the detection result may be lower than the detection limit within the 95%confidence interval,resulting in a negative result,and sampling can be performed again to ensure the result When x>0.564,k=2,the detection result cannot be lower than the detection limit within the 95%confidence interval,and the result is judged as unqualified.The established method was used to detect the random samples,and the results showed that the total detection rate was 0%and the detection results of all samples were undetected.