AOAC-RI ERP Book - FAOM METHOD.pdf

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HALL & KEULER: JOURNAL OF AOAC INTERNATIONAL VOL. 92, NO. 1, 2009 51
Table 1. Effect of delayed reading on sample absorbance values and percentage change in absorbance relative to
no time delaya
Time delay to reading, min
Incubation condition Glucose, g/mL 0 15 30 45 60
Standard solution:GOPODk reagent (0.5:2.5) Absorbance at 505 nm
35 C for 45 min 0 0.000 0.001 0.001 0.002 0.003
40 0.239 0.238 0.237 0.234 0.236
60 0.359 0.357 0.354 0.352 0.351
100 0.594 0.586 0.582 0.579 0.579
(Absorbance/0 time delay absorbance) 100
40 99.7% 99.1% 98.1% 98.8%
60 99.2% 98.6% 97.9% 97.8%
100 98.7% 98.0% 97.5% 97.5%
Absorbance at 505 nm
50 C for 20 min 0 0.000 0.001 0.003 0.003 0.003
40 0.238 0.240 0.242 0.237 0.235
60 0.358 0.357 0.356 0.353 0.351
100 0.589 0.582 0.580 0.577 0.570
(Absorbance/0 time delay absorbance) 100
40 100.5% 101.4% 99.6% 98.7%
60 99.9% 99.4% 98.7% 98.0%
100 98.8% 98.6% 98.0% 96.9%
Time delay to reading, min
0 10 20 30 40
Standard solution:GOPODk reagent (0.1:3.0) Absorbance at 505 nm
50 C for 20 min 0 0.000 0.002 0.004 0.000 0.001
400 0.455 0.453 0.452 0.445 0.444
600 0.674 0.671 0.671 0.662 0.656
1000 1.114 1.107 1.098 1.087 1.079
(Absorbance/0 time delay absorbance) 100
400 99.6% 99.3% 97.8% 97.5%
600 99.5% 99.5% 98.1% 97.3%
1000 99.4% 98.6% 97.6% 96.9%
a Values presented as least-squares means and calculated percentages.