Study On Analytical Methods Of N-nitrosamine Compounds In Cured And Smoked Meat Products

Nitrosamine compounds in cured and smoked meat products have the characteristics of low concentration and high risk.They can bring out serious toxicity to the human body,and excessive intake them will cause cancer.The methods for detecting N-nitrosamine compounds in food samples are often interfered by the characteristics of the food matrix itself.There are large differences in molecular weight and volatility of N-nitrosamine compounds.As the result,detecting volatile nitrosamines and non-volatile nitrosamines simultaneous is very hard.Now,development of an effective analytical method for detection of volatile nitrosamines and non-volatile nitrosamines in cured and smoked meat products at the same time is extremely important for food safety control.This study established an ultrasonic extraction-solid phase extraction method combined with high performance liquid chromatography-tandem mass spectrometry for detecting 13N-nitrosamine compounds in cured bacon products based on isotope internal standard method to quantify.According to the regulatory requirements of methodology verification,the linear relationship,precision,recovery rate,detection limit,quantification limit and matrix effect was investigated respectively.The conclusions are as follows:(1)An ultrasonic extraction-solid phase extraction method combined with a high performance liquid chromatography-mass spectrometer was used to determine 13 N-nitrosamine compounds in cured meat products.The optimum detection process was selected.It is found that the sample can be ultrasonically extracted with 10 m L of acetonitrile for 10 minutes,then frozen and degreased by n-hexane,purified by a neutral alumina solid phase extraction cartridge,then concentrated by a rotary evaporator at 40°C,and filtered by a PTFE ACRODISC CR13 filter membrane.Subsequently,gradient elution was carried out with 0.1%methanol aqueous solution-methanol as the mobile phase.The target product was separated by ACE Excel C18-AR chromatographic column.APCI~+combined with ESI~+was analyzed and monitored by the selected multiple reaction monitoring(MRM)mode.Finally,the internal standard method was used for quantification.(2)The methodological investigation of the method established above shows that the 13optimized N-nitrosamine compounds exhibit a good linear relationship during the linear range of1-20 ng/m L.The correlation coefficient R of the linear equation is greater than or equal to 0.9990.Limit of detection(LOD)is 0.0008-0.1200?g/kg.And the limit of quantification is 0.0020-0.4000?g/kg,which are all meet the actual requirements for the detection of N-nitrosamine compounds.The standard addition recovery rate of developed method at the three levels of 0.40?g/kg,2.0?g/kg and 8.0?g/kg is from 66%to 130%,and the relative standard deviation(RSD)is from 1.0%to 12.4%.The developed method reveals many advantages,such as simple and fast,high sensitivity,good precision,suitable for determining the content of 13 N-nitrosamine compounds in cured and smoked meat products.(3)The isotope internal standard method was used to investigate the influence of matrix effect on the quantification of 13 N-nitrosamine compounds.After comparison,it is found that each nitrosamine is subject to different degrees of matrix enhancement or matrix inhibition effects.It is indicated that the matrix matching calibration solution can be used for the accurate quantification of 13 kinds of nitrosamine compounds in pickled and smoked foods by the combination of isotope internal standard method and high performance liquid chromatography/mass spectrometry.