搜索
苎麻化学成分微波快速测定法的重复性和再现性研究文/冷鹃肖爱平程毅廖丽萍田小兰聂晴岚叶春玲摘要：研究了苎麻化学成分微波检测法的重复性和再现性，实验采用苎麻原麻样品在5台不同的微波炉上提取测定脂蜡、水溶物、果胶及半纤维素。采用统计方法分析了测试数据，剔除异常数据后计算了质量水平(m)、重复性限(r)和再现性限(R)，并说明了该方法得到的重复性限和再现性限的应用意义。关键词：微波法；苎麻；化学成分；格拉布斯法；狄克逊法；法科克伦法；重复性限；再现性限RepeatabilityandReproducibilityResearchonMicrowaveRapidTestMethodforRamieChemicalComponentsLENGJuan,XIAOAi-ping,CHENGYi,LIAOLi-ping,TIANXiao-lan,NIEQing-lan,YEChun-lin(InstituteofBastFiberCrops,ChineseAcademyofAgricultureSciences,Changsha410205，China)Abstract:Therepeatabilityandreproducibilityofmicrowavetestingchemicalcompositionoframiewerestudied.Fivemicrowaveovenswereappliedinthisexperimenttotestceride,hydrotrope,pectinandhemicelluloseinrawramiesamples.Statisticalmethodswereusedtoanalyzethetestdataandmasslevel(m),repeatabilitylimit(r)andreproducibilitylimit(R)arecalculatedafterabnormaldatahavebeeneliminated,andapplicationsignificanceofrepeatabilitylimitandreproducibilitylimitobtainedbythismethodwerealsoindicated.keywords:microwave,ramie；chemicalcomponents,Grubbs；Dixon.Corchran；repeatabilitylimit;reproducibilitylimit国内传统的分析测试方法通常采用允许差来衡量分析方法的精密度，近年来为了与国际接轨，新的检测方法与制、修订检测标准逐渐采用重复性和再现性来替代原有的允许差。而现行国家标准方法“苎麻化学成分定量分析方法GB/T5886-1986”中既无允许差的要求，也无重复性和再现性的规定。为此，拟对苎麻脂蜡、水溶物、果胶及半纤维素的微波快速测定法相应的重复性和再现性进行探讨，明确微波法检测苎麻化学成分的精度水平，为实际检测质量控制提供依据。1实验部分1.1仪器设备5台微波炉，品牌/型号分别为美的/KD21C-AN(B)、美的/KD20C-CF(B)、美的/KD21G-B1、格兰仕/GT02011YSL-V1、格兰仕/GT02011YSL-V2，对应仪器编号依次为Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ。1.2实验材料赣苎3号、圆叶青、96-12、0802、NC01、华苎4号、中苎1号和C20601共8个品种的苎麻原麻，对应样品编号依次为1、2、3、4、5、6、7、8号。1.3测试方法[1]实验选取的8个不同品种的苎麻原麻样品，每个样品作为1个水平，共有8个水平。8个样品分别由不同的操作者在5台不同型号的微波炉上提取测试，每个样品重复分析4次，每个检测参数得到4个分析结果。一台仪器所测的分析数据作为一个试验室的分析结果，这样可以认为有5个试验室参加测试。2测试结果和数据处理[2-3]2.1数据整理按照1.3方法进行测试，测试结果略。微波炉Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ分析结果分别作为第1，2，3，4，5个试验室分析结果。将一个试验室测试一个样品的数据作为一个单元，共40个单元，每个单元每个检测参数有4个数据。分别计算各单元的平均值和方差，分别见表1和表2。表1单元数据平均值（yi）参数编号ⅠⅡⅢⅣⅤ脂蜡/%10.330.310.300.340.3620.510.550.490.500.3430.520.510.550.530.4140.390.460.470.440.3450.400.370.380.360.3360.290.230.210.280.1570.550.570.520.530.3980.410.380.360.400.30水溶物/%18.337.318.378.327.9226.665.555.656.165.5137.985.786.127.906.8146.716.786.096.695.4555.485.785.896.405.4765.385.055.085.315.7175.395.856.265.355.4587.217.247.308.096.74果胶/%15.555.355.795.454.8324.294.345.074.264.0634.445.215.344.424.1544.484.685.034.434.7755.494.524.265.454.2264.754.284.454.713.9075.195.164.975.154.8786.285.704.836.235.05半纤维素/%114.3914.1615.0114.3413.99212.1611.9112.2912.1511.53313.2112.2612.8515.2113.21415.4013.7613.8515.4813.92513.2212.3113.1513.3412.95612.3312.6313.2513.0712.44712.6711.6412.0712.6410.93815.9014.9615.0015.9814.13表2单元数据方差(s2i)参数编号ⅠⅡⅢⅣⅤ脂蜡（×10-9）13.8904.9304.89218.3012.3023.8602.8872.80024.9021.9032.6991.6680.6674.0333.03346.7595.7795.7580.4660.96657.6288.6678.6259.6676.69765.2353.2883.2334.1585.13876.5515.5504.55011.1012.1686.6704.2386.26821.8910.71水溶物（×10-6）12.7963.1822.7945.1814.14122.4511.4762.3302.4653.425311.2012.5812.1913.5510.5541.16613.290.11614.2811.0855.0927.0334.0896.0315.03361.38820.660.38417.0812.0870.9901.5250.7150.5281.53887.77211.107.866121.128.150果胶（×10-6）16.155.335.134.905.0122.222.231.210.921.1438.4611.5510.484.545.0447.407.386.401.602.6853.413.332.391.312.3364.213.463.2210.9111.9173.681.690.675.234.1284.892.742.883.032.05半纤维素（×10-5）11.2902.2000.1601.1902.20020.1450.1990.0500.0430.14331.1550.1840.4100.1540.95541.6630.4990.6450.4490.86052.5501.5702.0691.5302.05061.492.460.0011.2501.84070.9691.7800.7190.7690.98980.8831.1650.6300.1611.1652.2异常数据检验2.2.1检查单元内数据采用格拉布斯(Grubbs)法检验各单元内的异常值。即将各单元每个检测参数的4个值按从小到大次序排列，分别记为X1，X2，X3，X4,则Grubbs的统计量Gn为(X-X1)/S与(X4-X)/S中较大者。其中X为单元数据的平均值，S为单元数据的标准差。计算各单元检测参数Gn见表3。查表得测量次数n=4，显著水平α=1%，Gn临界值为1.496，α=5%,Gn临界值为1.481。检查表3发现第Ⅲ实验室6号试样半纤维素第3个检测数据、第Ⅳ实验室的4号试样脂蜡第1个检测数据、6号试样水溶物第1个检测数据与半纤维素第2个检测数据、第Ⅴ实验室2号与3号试样脂蜡的第2个检测数据及5号试样第1个检测数据存在高度异常，删去上述异常数据后，再次采用Grubbs检验不存在异常。表3单元格拉布斯统计量（Gn）参数编号ⅠⅡⅢⅣⅤ脂蜡11.4661.3861.4881.4781.39021.3881.4781.3781.0780.38631.4601.3601.2601.40041.2101.2821.3811.6811.28351.2911.1811.2811.2211.14161.2901.1911.2911.2411.14171.4091.4201.4001.3951.43081.4861.3411.4460.9461.441水溶物11.4631.4631.3621.3061.45321.2461.1451.4451.0881.14531.3231.1231.2231.1341.11341.2131.2131.1130.7111.22351.3371.2561.2361.4041.24661.4291.3241.3281.6401.33071.1481.4461.3461.4371.34581.2601.3511.1501.3081.362果胶11.3221.1201.0881.4291.58821.3831.4741.2901.4841.69031.2531.1531.4261.0531.22641.3021.0321.4371.0001.33851.3961.4751.4501.4951.38061.2871.1681.3911.881.49171.4581.4201.3871.4381.48681.4211.4871.2841.3271.383半纤维素11.3381.2871.2501.2371.15021.2371.3381.3001.4381.33031.4331.3961.3601.3331.46141.1521.2641.3571.2541.45851.21381.1191.5131.6331.41361.1381.1191.5131.6331.41371.2911.3971.2981.3921.39781.1291.3211.2981.4211.3972.2.2检查单元方差采用科克伦(Cochran)检验方法检验在同一水平下单元方差是否存在异常。Cochran的统计量C=S2max/∑S2i，其中S2max为同一水平下的最大方差；分母为同一水平下的各方差之和。计算各水平下的C值，结果见表4。查表可知:测量次数n=4，实验室数P=5，显著水平α=1%,C临界值为0.696；α=5%,C临界值为0.598。检查表4，无异常单元。表4科克伦统计量脂蜡水溶物12345678123456780.4130.4420.3330.3410.2340.2490.3050.4400.2290.2820.2260.3580.2210.3990.2900.280果胶半纤维素12345678123456780.2250.2610.2880.2910.2670.3530.2740.3140.3120.3430.4040.4040.2610.3400.2320.3032.2.3检查