Fig. 5

a Relationship between depth of colour (log-transformed) produced, using the colorimetric Test Kit, and the deltamethrin concentration (mg/m²), determined using HPLC–DAD, for 20 LLINs; and b depth of colour range exhibited using the colorimetric Test Kit across a range of deltamethrin concentrations from 0 to 80 mg/m². In Fig. a, the orange line (dark and light) indicates nets that fell into the “Fail” category of the colorimetric test (< 15 mg/m²), while the green line (light and dark) indicates nets that fell into the “Pass” category