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Assessment of analytical methods to determine pyrethroids content of bednets
Castellarnau, Marc Ramón-Azcón, Javier Gonzalez-Quinteiro, Yolanda López, Jordi F. Grimalt, Joan O. Marco, María-Pilar Nieuwenhuijsen, Mark Picado, Albert
Castellarnau, Marc
Ramón-Azcón, Javier
Gonzalez-Quinteiro, Yolanda
López, Jordi F.
Grimalt, Joan O.
Marco, María-Pilar
Nieuwenhuijsen, Mark
Picado, Albert
Abstract
Objective To present and evaluate simple, cost‐effective tests to determine the amount of insecticide on treated materials. Methods We developed and evaluated a competitive immunoassay on two different platforms: a label‐free impedimetric biosensor (EIS biosensor) and a lateral flow. Both approaches were validated by gas chromatography (GC) and ELISA, gold standards for analytical methods and immunoassays, respectively. Finally, commercially available pyrethroid‐treated ITN samples were analysed. Different extraction methods were evaluated. Results Insecticide extraction by direct infusion of the ITN samples with dichloromethane and dioxane showed recovery efficiencies around 100% for insecticide‐coated bednets, and > 70% for insecticide‐incorporated bednets. These results were comparable to those obtained with standard sonication methods. The competitive immunoassay characterisation with ELISA presented a dynamic range between 12 nm and 1.5 μm (coefficient of variation (CV) below 5%), with an IC50 at 138 nm, and a limit of detection (LOD) of 3.2 nm. EIS biosensor had a linear range between 1.7 nm and 61 nm (CV around 14%), with an IC50 at 10.4 nm, and a LOD of 0.6 nm. Finally, the lateral flow approach showed a dynamic range between 150 nm and 1.5 μm, an IC50 at 505 nm and a LOD of 67 nm. Conclusions ELISA can replace chromatography as an accurate laboratory technique to determine insecticide concentration in bednets. The lateral flow approach developed can be used to estimate ITN insecticide concentration in the field. This new technology, coupled to the new extraction methods, should provide reliable guidelines for ITN use and replacement in the field.
Keywords
Date
2017
Type
Journal article
Journal
Tropical Medicine and International Health
Book
Volume
22
Issue
1
Page Range
41-51
Article Number
ACU Department
Mary MacKillop Institute for Health Research
Faculty of Health Sciences
Faculty of Health Sciences
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Open Access Status
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Controlled