Development of a Simple Dipstick Assay for Operational Monitoring of DDT
Fig 1
Schematic graph of the dipstick assay for determination of DDT.
The assay operates through the concomitant release of chloride ion (Cl-) during alkaline-catalyzed DDT dehydrochlorination reaction that is measured by chloride Quantab Test Strips as follows: in Step 1 DDT is dissolved in heptane while contaminating ions remain undissolved and removed through transfer of DDT to a new tube. In Step 2 Cl- is released by KOH, neutralized in Step 3 with ~1/10th volume of aqueous acetic acid, which concentrates Cl- into the bottom aqueous phase. In Step 4, Quantab strip measurements of Cl- are taken from the aqueous phase allowing estimation of DDT concentration.