主题：【求助】看看我变色酸法做的甲醛标线有什么问题？

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hxueren

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发表于：2008/12/14 23:05:19 楼主管理分享倒序浏览只看楼主回复私聊

变色酸0.1%，Tube No. Volume, mL
NaHSO3（1%） Solution B（10ug/ml甲醛的1%的NaHSO3）
Std1 4.0ml 0.00ml
Std2 3.9ml 0.10ml
Std3 3.7ml 0.30ml
Std4 3.5ml 0.50ml
Std5 3.3ml 0.70ml
Std6 3.0ml 1.00ml
然后每个加入6.00ml浓硫酸摇匀，2小时后在紫外-可见分光光度计，580nm处以水为参比测试，结果如下;

Report time 2008-12-5 15:28:11
Method E:\formaldehyde in furniture\method\ASTM
D6007-2.MCN
Batch name E:\formaldehyde in furniture\data\20081205.BCN
Application Concentration 3.00(339)
Operator

Instrument Settings
Instrument Cary 300
Instrument version no. 9.00
Wavelength (nm) 580.00
Ordinate Mode Abs
SBW (nm) 1.5
Ave Time (sec) 0.100
Beam mode Double auto select
Beam interchange Normal
Replicates 1
Standard/Sample averaging OFF
Weight and volume corrections OFF
Fit type Linear
Min R2 0.95000
Concentration units ug

Comments:

Zero Report

Read Abs nm
________________________________________________
Zero (-0.0173) 580.00

Calibration
Collection time 2008-12-5 15:29:58

Standard Concentration F Readings(ABS)
ug
________________________________________________
Std 1 0.0000 0.0134
Std 2 1.0000 0.0754
Std 3 3.0000 0.1921
Std 4 5.0000 0.3063
Std 5 7.0000 0.4204
Std 6 10.0000 0.5967

Calibration eqn Abs=0.05805*Conc+0.01586
Correlation Coefficient 0.99993
Calibration time 2008-12-5 15:35:47

Analysis
Collection time 2008-12-5 15:35:47

Sample Concentration F Readings
mg/L
________________________________________________
MB-1 -0.0041 0.0156
MB-2 -0.0229 0.0145
MB-3 -0.0229 0.0145
MB-4 -0.0190 0.0148
MB-5 -0.0414 0.0135
MB-6 -0.0265 0.0143
MB-7 -0.0286 0.0142
MB-8 -0.0267 0.0143
MB-9 0.0150 0.0167
MB-10 -0.0244 0.0144
MB-11 -0.0134 0.0151
MB-12 -0.0360 0.0138
MB-13 -0.0252 0.0144
MB-14 -0.0257 0.0144
MB-15 -0.0088 0.0153
MB-16 -0.0159 0.0149
MB-17 -0.0143 0.0150
MB-18 -0.0179 0.0148
MB-19 0.0198 0.0170
MB-20 -0.0252 0.0144
MB-21 -0.0277 0.0142
MB-22 -0.0402 0.0135
Std 2 1.0273 0.0755
Std 2 1.0268 0.0755
Std 2 1.0303 0.0757
Std 2 1.0290 0.0756
Std 2 1.0284 0.0756
Std 3 3.0373 0.1922
Std 3 3.0223 0.1913
Std 3 3.0250 0.1915
Std 3 3.0220 0.1913
Std 3 3.0203 0.1912
Std 4 4.9840 0.3052
Std 4 4.9859 0.3053
Std 4 4.9881 0.3054
Std 4 4.9838 0.3052
Std 4 4.9864 0.3053
Std 5 6.9923 0.4217
Std 5 6.9751 0.4207
Std 5 6.9704 0.4205
Std 5 6.9635 0.4201
Std 5 6.9640 0.4201
Std 6 9.9910 0.5958
Std 6 9.9862 0.5955
Std 6 9.9862 0.5955
Std 6 9.9311 0.5923
Std 6 9.9328 0.5924

这些点又重新测了，怎么误差那么大啊，从吸光度看都差不多，但是从等式算出来就不一样了，差别还比较大的？尤其是空白吸光度0.0145 ，算出来却是-0.0229，而Std 1 0.0000 0.0134； 0.0145比0.0134还大怎么是负值？
另外根据这些能不能算检出限?怎么算？我算的怎么比空白还小很多啊？