苎麻化学成分微波快速测定法的重复性和再现性研究

1、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Repeatability and Reproducibility Research on Microwave Rapid Test Met

2、hod for Ramie Chemical Components LENG Juan, XIAO Ai-ping, CHENG Yi , LIAO Li-ping , TIAN Xiao-lan , NIE Qing-lan, YE Chun-lin(Institute of Bast Fiber Crops,Chinese Academy of Agriculture Sciences ,Changsha 410205，China)Abstract:The repeatability and reproducibility of microwave testing chemical com

3、position of ramie were studied. Five microwave ovens were applied in this experiment to test ceride, hydrotrope, pectin and hemicellulose in raw ramie samples . Statistical methods were used to analyze the test data and mass level (m), repeatability limit (r) and reproducibility limit(R) are calcula

4、ted after abnormal data have been eliminated,and application significance of repeatability limit and reproducibility limit obtained by this method were also indicated.keywords:microwave,ramie；chemicalcomponents,Grubbs；Dixon.Corchran；repeatability limit;reproducibility limit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

5、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/T 5886-1986”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

6、号依次为、。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2-32.1 数据整理按照 1.3方法进行测试，测试结果略。微波炉、分析结果分别作为第1，2，3，4，5个

7、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.

8、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/%15.555.355.795.454.8324.294.345.074.264.0634.445.215.344.424.1544.484.685.034.434.7755.494.524.265.454.2264.754.284.454.713.9075.195.164.975.154.8786.285.70

9、4.836.235.05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)参数编号脂蜡（10-9）13.8904.9304.89218.3012.3023.8602.8872.80024.902

10、1.9032.6991.6680.6674.0333.03346.7595.7795.7580.4660.96657.6288.6678.6259.6676.69765.2353.2883.2334.1585.13876.5515.5504.55011.1012.1686.6704.2386.26821.8910.71水溶物（10-6）12.7963.1822.7945.1814.14122.4511.4762.3302.4653.425311.2012.5812.1913.5510.5541.16613.290.11614.2811.0855.0927.0334.0896.0315.0336

11、1.38820.660.38417.0812.0870.9901.5250.7150.5281.53887.77211.107.866121.128.150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）11.2902.2000.1601.1902.20020.145

12、0.1990.0500.0430.14331.1550.1840.4100.1540.95541.6630.4990.6450.4490.86052.5501.5702.0691.5302.05061.492.460.0011.2501.84070.9691.7800.7190.7690.98980.8831.1650.6300.1611.1652.2 异常数据检验 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

13、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=1%，Gn临界值为1.496，=5%, Gn临界值为1.481。检查表3发现第实验室6号试样半纤维素第3个检测数据、第实验室的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）参数编号脂蜡11.4661.3861.4881.4781.39021.3881.4781.3781.0780.38631

14、.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.

15、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11.3381.2871.2501.2371.1502

16、1.2371.3381.3001.4381.33031.4331.3961.3601.3331.46141.1521.2641.3571.2541.45851.21381.1191.5131.6331.41361.1381.1191.5131.6331.41371.2911.3971.2981.3921.39781.1291.3211.2981.4211.397 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。

17、查表可知 :测量次数n=4，实验室数P=5，显著水平=1%,C临界值为0.696；=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12345678123456780.2250.2610.2880.2910.2670.3530.2740.3140.3120.3430.4040.4040.2610.3400.2320.303 检查单元平均值采用格拉布斯(Grubb

18、s)法检验同一水平下单元均值是否存在异常，按方法计算得到表5的Gn数据。查表可知 :实验室数p=5，显著性水平P=1%，Gn临界值为1.764；P=5%，Gn临界值为1.715。检查表5，无异常数据。表5 均值格拉布斯统计量（Gn）脂蜡水溶物12345678123456781.2571.7401.6471.4301.5451.4101.4091.6061.6361.5141.1351.5571.5791.5421.0261.582果胶半纤维素12345678123456781.7541.4921.1921.4501.1051.4951.4241.1901.0081.5981.6741.1401

19、.6381.3081.4501.386采用狄克逊(Dixon)法检验同一水平下单元均值是否存在异常。将每个水平下5个实验室均值按从小到大次序排列，分别记为X1，X2，X3，X4，X5，则统计量D10为(X2-X1)/(Xn-X1)与(Xn-1)/(Xn-X1)的较大值，按上面公式计算得到D10数据，见表6。查表可知:实验室数p=5，显著性水平=1%，D10临界值为0.821；=5%，D10临界值为0.710。检查表6未发现异常数据。表6 均值狄克逊统计量脂蜡水溶物12345678123456780.3330.7140.7860.4090.4260.4290.2860.5450.5750.435

20、0.1550.4810.6130.4720.4510.585果胶半纤维素12345678123456780.7880.5240.2270.4330.3150.4470.3130.1520.6080.5000.7080.0520.5730.2170.4080.4492.3 总平均值(m)和重复性限(r)及再现性限(R)的计算通过2.2的异常数据检验，剔除异常数据后，整理数据得到表7。表7 经异常数据剔除后的统计数据参数脂蜡编号123 456780.333.8900.513.8600.522.6990.396.5790.407.6280.295.2350.556.5510.416.6700.314

21、.9300.552.8870.511.6680.465.7790.378.6670.233.2880.575.5500.384.2380.304.8920.492.8000.550.6670.475.7580.388.6250.213.2330.524.5500.366.2680.3418.300.5024.900.534.0330.440.4660.369.6670.284.1580.5311.100.4021.890.3612.300.3421.900.413.0330.340.9660.336.6970.155.1380.5912.160.3010.71参数 水溶物编号123 45678

22、8.332.7696.662.4517.9811.206.711.1665.485.0925.381.3885.390.9907.217.7727.313.1825.551.4765.7812.586.7813.295.787.0335.0520.665.851.5257.2411.108.372.7945.652.3306.1212.196.090.1165.894.0895.080.3846.260.7517.307.8668.325.1816.162.4657.9013.556.6914.286.406.0315.3117.085.350.5288.09121.127.924.1415.

23、513.4256.8110.555.4511.085.475.0335.7112.085.451.5386.748.150参数果胶编号123 456785.556.154.292.224.448.464.487.405.493.414.754.215.193.686.284.895.355.334.342.235.2111.554.687.384.523.334.283.465.161.695.702.745.795.135.071.215.3410.485.036.404.262.394.453.224.970.674.832.885.454.904.260.924.424.544.431.

24、605.451.314.7110.915.155.236.233.034.835.014.061.144.155.044.772.684.222.333.9011.914.874.125.052.05参数 半纤维素编号123 4567814.391.29012.160.14513.211.15515.401.66313.222.55012.331.49012.670.96915.900.88314.162.20011.910.19912.260.18413.760.49912.311.57012.632.46011.641.78014.961.16515.010.16012.290.05012

25、.850.41013.850.64513.152.06913.250.00112.070.71915.000.63014.341.19012.150.04315.210.15415.480.44913.341.53013.071.25012.640.76915.980.16113.992.20011.530.14313.210.95513.920.86012.952.05012.441.84010.930.989143.130.165注: 第实验室的4号试样脂蜡，第实验室6号试样水溶物，第实验室6号试样与第实验室5号试样半纤维素的（检测数据）为3，其余均为4；均值yi /10-2 , 方差脂蜡

26、si2/10-9，水溶物与果胶si2/10-6，半纤维素si2/10-5。根据GB/T 6379.22004中和的定义： (1) (2) (3) (4) (5) (6) (7)sR2=sL2+sr2 (8) (9) (10) 其中：p为实验室数，T为总和，yi为测试结果，ni为重复次数，m为测试特性总平均值或质量水平，sr2、sr分别为重复性方差与标准差，sR2、sR分别为再现性方差与标准差。按照以上的公式，对应表7数据，可得到各水平下的m,r,R，结果见表8。对表8进行观察，看不出m与r及m与R之间的明显的依赖关系，因而表中的r与R的平均值可以作为微波快速测定法测定苎麻脂蜡、水溶物、果胶及半纤维素的重复性限(r)和再现性限(R)。表8 各水平下的m,r,R参数脂蜡(%) 水溶物(%) 编号1234567812345678m0.330.480.500.420.370.230.550.378.055.916.926.345.804.095.667.32r0.030.030.010.020.030.020.030.030.530.440.970.790.650.880.290.86R0