Determination of the insecticide imidacloprid in fruit juices using micellar high-performance liquid chromatography

A simple and reliable HPLC method was developed to determine imidacloprid, a chloronicotinyl insecticide that has a highly specific affinity to the nicotinic acetylcholine receptor of insects, above its permissible limit of consumption in fruit juices (orange, apple, and a mixture of pineapple and pear). Samples were injected directly into a Kromasil C18 column, without any pretreatment step, using the micellar mobile phase 0.10 M sodium dodecyl sulfate and 2.5% (v/v) propanol buffered at pH 7 and UV detection at 210 nm. Under these conditions, imidacloprid was eluted in < 4 min with no interference by the endogenous compounds of the juice fruits. The analytical parameters' linearity (r > 0.9998) and intraday and interday precision (RSD 0.1-2.8 and 0.07-7%, respectively) were obtained in the method validation. LOD and LOQ were calculated to be 0.4 and 1.5 ng/mL, respectively. Recoveries were in the 98-103% range. The simplicity of the method makes it a good candidate for application in routine analysis in the area of food control and quality evaluation.