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目的利用英蓝在线渗析技术净化处理经超声直接提取后含大量有机质及高盐的样品,建立各类食品中NO-2、NO3-的电导、紫外联用分析方法。方法样品经切碎匀浆后,超声提取30 min后,用定量滤纸过滤,弃去最初过滤液10ml,中间滤液直接置于样品管中,进样渗析分析,采用Metrosep A Supp 7-250/4.0阴离子交换柱,压力11.0 MPa;柱温45℃,淋洗液为3.8 mmol/L碳酸钠,流速0.8 ml/min,抑制电导法检测样品的NO2-、NO3-,对于高盐样品串联紫外可见光检测器,在波长215 nm下测定NO2-。结果在该色谱条件下,电导检测器在36 min内完成NO2-、NO3-的分析;标准曲线在0.05~0.5 mg/L范围内线性关系良好(r=0.9998和r=0.9999);紫外检测器NO2-在0.05~0.5 mg/L范围内线性关系良好(r=0.9999),两种检测器的样品峰面积RSD(n=7)为1.75%~2.30%;加标回收率为94.8%~107.4%。NO2-和NO3-的电导检测法检出限分别为0.0092 mg/kg和0.017 mg/kg,紫外检测器方法 NO2-检出限为0.0126 mg/kg。结论该方法适用于各类不同含盐量食品中NO2-、NO3-等肮脏样品的超声提取后直接进样渗析法测定。
OBJECTIVE To purify the samples containing large amounts of organic matter and high salt directly after ultrasonic extraction by British blue dialysis technology to establish the method for the conductance and ultraviolet spectrometry of NO-2 and NO3- in various foods. Method After the sample was homogenized and homogenized by ultrasonic extraction for 30 min, it was filtered with quantitative filter paper and the initial filtrate was discarded. The intermediate filtrate was directly placed in the sample tube. The sample was analyzed by dialysis using Metrosep A Supp 7-250 / 4.0 Anion exchange column, pressure 11.0 MPa; the column temperature was 45 ℃, the eluent was 3.8 mmol / L sodium carbonate, the flow rate was 0.8 ml / min, inhibition of NO2-, NO3- by conductivity method, Device, measured at a wavelength of 215nm NO2-. Results Under the chromatographic conditions, the conductivity detector performed NO2- and NO3- analysis within 36 min. The calibration curve showed good linearity (r = 0.9998 and r = 0.9999) in the range of 0.05-0.5 mg / L. The UV detector The linear range of NO2- was in the range of 0.05-0.5 mg / L (r = 0.9999). The peak area RSD (n = 7) was 1.75% ~ 2.30% for both detectors and the recoveries were 94.8% -107.4 %. The detection limits of NO2- and NO3- were 0.0092 mg / kg and 0.017 mg / kg, respectively. The detection limit of NO2- and NO3- by NO2- was 0.0126 mg / kg. Conclusion This method is suitable for the determination of NO2-, NO3- and other dirty samples in different salt content foods by direct injection and dialysis after ultrasonic extraction.