YSI 2900 - 8.2.10 Lactose

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8.2.10 Lactose
This is a direct reading of lactose in solution at the enzyme sensor. The enzyme Galactose oxidase is immobilized in
the enzyme membrane.
Lactose + O
2 Gal Oxidase
H
2
O
2
+ Galactose Dialdehyde Derivative
System Buffer
YSI 2705
Calibrator Std
YSI 2783
Linearity Std
YSI 2784
Membrane
YSI 2702
Membrane
Color
White
Detection
Range
0.05–25 g/L
Calibration
Point
5.0 g/L
Linearity Check
Point
25.0 g/L
Sample Size
25 µL
End Point
30 sec
Precision
(CV,n=10)
2% or 0.02 g/L,
whichever is
greater
Linearity
±2%
(0.05 to Cal Point)
±5%
(Cal Point to Range
Max)
Typical Working
Life
10 days
Note: See Appendix B – Concentration
Unit Conversion if concentration unit
conversion is required.
Special Considerations:
• If sample dilution is required, use reagent water.
• The sample should be galactose-free. Galactose,
glycerol, and other galactosides such as raffinose and
stachyose are substrates for galactose oxidase. They
may interfere by producing artificially high lactose
readings.
• The enzyme membrane integrity test involving the use of
YSI 2363 Potassium Ferrocyanide solution is not
informative since ferrocyanide exists in the 2705 system
buffer.