Development, validation, and application of an acetylcholinesterase-biosensor test for the direct detection of insecticide residues in infant food

Abstract

A highly sensitive and rapid food-screening test based on disposable screen-printed biosensors was developed, which is suitable for monitoring infant food. The exposure of infants and children to neurotoxic organophosphates and carbamates is of particular concern because of their higher susceptibility to adverse effects. The European Union has therefore set a very low limit for pesticides in infant food which must not contain concentrations exceeding 10 µg/kg for any given pesticide. The maximum residue limit (MRL) has been set to be near the determination threshold that is typically achieved for pesticides with traditional analytical methods. The biosensor method could detect levels lower than 5 µg/kg and thus clearly fulfills the demands of the EU. To substantiate these measurements, recovery rates were determined and amounted on average to 104 % in food.

Biosensors based on cholinesterase inhibition for insecticides, nerve agents and aflatoxin B1 detection (review)

“…As reported in literature, the optimum pH for the free enzyme is pH= 8 while the pH can be shifted when the enzyme is immobilised to pH=7 as in the case of AChE immobilised onto Ca-alginate gel beads [157]. However the acid pH should be avoided, in fact in the case of insecticide detection during wine fermentation [118] or in orange juice [158] it is necessary to adjust the pH towards neutral value.…”

“…The analytical system was successfully validated and applied to 26 fruit and vegetable samples and 23 samples of processed infant food [158]. The organophosphorus and carbammic insecticides were also measured in extract of sheep wool [183], potable, river and lake water samples [47, 133,184], milk [185], grape and vine leaf samples [186,187], wheat and durum wheat [188][189][190], apple skin [191], orange juice [165], garlic [192], lettuce, rice, onion [193,194], in samples of fruit, vegetable and dairy product [48,195] and directly in tomato [196].…”

Utilização de técnicas eletroanalíticas na determinação de pesticidas em alimentos

“…Os estudos são baseados no efeito da inibição da enzima pela presença do pesticida organofosforado. A técnica aplicada quando estes tipos de eletrodos são utilizados, geralmente, é a detecção potenciométrica, que possibilita a quantificação de uma ampla variedade de pesticidas organofosforados em alimentos 56,57 e bebidas 58,59 , devido à sua alta eficiência e seletividade.…”

Cholinesterase-based biosensors

“…In the export and import of food materials portable biosensors with quick response are convenient for fast detection 151 . Biosensors based on cholinesterase were used for determination of pesticides in food 40,44,66,137,139,[176][177][178][179] , water 34,38,40,177,180 and soil 52 . The most studied pesticides are paraoxon, carbofuran, aldicarb, dichlorvos and diazinon.…”