Explain4 marksStandard
A student uses glucose test strips to estimate the concentration of glucose in urine samples. The strips contain glucose oxidase, peroxidase, and a chromogen. After adding the urine, the strip is left for 30 seconds, then the colour is compared to a colour chart. The chart shows the following colours for known glucose concentrations:
| Glucose concentration (mmol dm⁻³) | Colour |
|---|---|
| 0 | White |
| 2 | Pale blue |
| 5 | Medium blue |
| 10 | Dark blue |
| 20 | Very dark blue |
Explain how the test strip enables the concentration of glucose to be estimated.