5 7 Vol. 5 No. 7 2014 7 Journal of Food Safety and Quality Jul., 2014 胡彩霞 *, 李红, 刘美霞, 任丽, 李秋琴, 王佳, 马文丽, 宋晓东 (, 011517) 摘要 : 目的 方法,,,,, 结果 80%~110%, 90%~110%, 10% 结论,, 关键词 : ; ; ; ; ; ; ; Determination of nitrate and nitrite content in milk and dairy products using ion chromatography HU Cai-Xia *, LI Hong, LIU Mei-Xia, REN Li, LI Qiu-Qin, WANG Jia, MA Wen-Li, SONG Xiao-Dong (Inner Mongolia Mengniu Dairy Group Co. Ltd., Hohhot 011517) ABSTRACT: Objective To improve the pretreatment method of national standard to detect nitrate and nitrite in Milk and dairy products. Methods Samples were extracted by acetonitrile, and after protein and fat precipitation, the extract was purified by anion exchange column, potassium hydroxide solution as leached solution. Nitrate and nitrite were detected by conductivity detector. Results The recoveries of nitrate and nitrite were 80%~110% and 90%~110% respectively, and the precision of the method were within 10%. Conclusion This method can improve the detection accuracy and reduce the detection error, and is suitable for the quantitative detection of nitrate and nitrite in milk and dairy products. KEY WORDS: nitrate; nitrite; ion chromatography; pre-treatment; improvement; acetonitrile; milk; dairy products 1 引言,,,, 0.2~0.5 g,,, C E,,, GB5009.33-2010,,,, * 通讯作者 :,, E-mail: mnwlp88@163.com *Corresponding author: HU Cai-Xia, Researcher, Inner Mongolia Mengniu Dairy Group Co., Ltd., Hohhot 011517. E-mail: mnwlp88@163.com
2236 5,,,,,,,,,, 2 材料与方法 2.1 材料与试剂 : 18.2 Ω cm MILLIPORE : () : () : (NO 2- )(1000 mg/l, ) (NO 3- )(1000 mg/l, ) : ( NO 2-, )( NO 3-, ) : (NO 2- ) (NO 3- ) 1.0 ml 10 ml 100 ml,, NO 2- NO 3-10.0 mg/l 100.0 mg/l 2.2 仪器与设备 ():,,, 100 µl ( ) IKA IKA EImasonic : 0.1 mg Sartorius : 10000 r/min, 30 ml 50 ml 0.22 µm / : 2.5 ml 5.0 ml : C 18 2.3 实验方法 2.3.1 测定步骤 (1) 10.0000 g(, 2 g,, 0.1 mg) 30 ml 50 ml, 5 ml, 5~10 min, 15 ml, 5 min, 10000 r/min 10 min, 5 ml, 20 ml (4 ) : 4, (2) 15 ml, 0.22 μm IC-RP, 3 ml/min, 6 ml, (IC-RP ) (3) : 1 : IonPac AS11-HC, 4 250 mm ; IonPac AG11-HC, 4 50 mm( ), ; 2 : ; : KOH, 0~48 min, 3 mmol/l; 48~48.1 min, 3~50 mmol/l; 48.1~56 min, 50 mmol/l; 1.30 ml/min; 40 3 1.30 ml/min; 4 : 40 ; 5 : ; 6 : ; : 100 µl 2.3.2 测定 (1),,, 0.00 0.02 0.05 0.10 0.15 0.20 mg/l; 0.00 0.20 0.50 1.00 1.50 2.00 mg/l,, (2) 100 µl,,,, (μs) 2.3.3 结果计算 ( NO - 2 )( NO - 3 ) :
7, : 2237 C V f 1000 X= -------------------- M 1000 : X ; C (mg/l); V (ml); f ; M (g) : 1.5, ( ) ; 1.37, ( ) [1] 2.3.4 精密度 10% 2.3.5 检出限 0.2 mg/kg 0.4 mg/kg 3 结果与讨论,, 0.01~0.1 mg/kg 0.02~0.2 mg/kg 0.05~0.5 mg/kg 0.1~1.0 mg/kg 0.15~ 1.5 mg/kg 0.2~2.0 mg/kg, R 2 3 9, 1 2 7,,, 0.22 µm,,, 3 3.1 回收率能达到实验既定要求,,, 1 3.2 改进前处理方法与原国标方法沉淀剂不同处 3%, 2 ml,,,,,,,, 3.3 提高了检测效率, 缩短了前处理时间 30 min,,, ;,,, 20~25 min 1 Fig. 1 Nitrite standard curve pattern
2238 食品安全质量检测学报 第5卷 图 2 硝酸盐标准曲线图谱 Fig. 2 Nitrate standard curve chart patterns Fig. 3 图 3 样品测定硝酸盐和亚硝酸盐色谱图谱 Chromatogram of determination of nitrate and nitrite in the sample 本方法亚硝酸盐加标回收率为 86.8% 109.1%; 果见表 2 硝 酸 盐 加 标 回 收 率 为 95.9% 107.8%, 依 据 GB/ 精密度检测均在 10%以内 T27404-2008,被测组分含量在 0.1 1 mg/kg 时, 回收 取奶粉依据 GB5009.33-2010 第一法样品前处理 率在 80% 110%, 改进后方法回收率能满足此规定 3.4 方法重复性实验 取纯牛奶依据本方法进行精密度试验, 检测结 方法进行精密度试验, 检测结果见表 3 GB5009.33-2010 第一法中, 前处理方法检测样 品重复性均超出 10%的范围内
7, : 2239 Table 1 表 1 以纯牛奶为本底, 依据 GB/T27404 推荐加标量按照以上方法测定结果 Pure milk as substrate, the measurement results according to the above method based on GB/T27404 recommend adding scalar (g) NO 2 - % NO 3 - % 1 11.1193 0.0071 / 0.2055 / 0.091 3.165 10.4582 0.0035 / 0.1353 / + 5 10.5498 0.0872 1.55 102.6 0.2733 4.436 97.9 + 5 10.5985 0.0896 1.59 105.9 0.2809 4.539 106.3 2 10.018 0.0145 / 0.1356 / 0.33 2.351 10.0582 0.0171 / 0.1400 / + 5 10.2103 0.1006 1.85 98.3 0.2169 3.638 95.9 + 5 10.0276 0.1032 1.93 107 0.2189 3.738 101.5 + 5 10.0961 0.0874 1.62 86.8 0.2217 3.760 103.8 + 10 10.3586 0.1836 3.32 103 0.3136 5.184 107.1 + 10 10.0335 0.1869 3.49 105.6 0.3102 5.294 107.8 + 10 10.1006 0.1923 3.57 109.1 0.3089 5.237 106.4 Table 2 表 2 乳样重复性检测结果 Reproducible test results of milk samples m(g) C(mol/L) % 1 2 10.7686 0.3201 5.573 10.5549 0.3151 5.112 10.8634 0.0372 0.642 10.0356 0.0339 0.633 8.63 1.41 3 10.4315 0.1666 2.735 8.42 10.4281 0.1398 2.514 Table 3 表 3 乳样重复性检测结果 Reproducible test results of milk samples m(g) C(mol/L) % 1 2 1.2645 0.0386 4.48 1.2657 0.0474 5.59 1.2644 0.0341 3.91 1.2622 0.0385 4.49 22.05 13.80 3 1.2888 0.0452 5.22 20.16 1.2511 0.0532 6.39 4 结论 :, :,,
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