Potentiometric perchlorate determination at nanomolar concentrations in vegetables. (15th July 2017)

• Record Type: Journal Article
• Authors: Leoterio, Dilmo M.S.; Paim, Ana Paula S.; Belian, Mônica F.; Galembeck, André; Lavorante, André F.; Pinto, Edgar; Amorim, Célia G.; Araújo, Alberto N.; Montenegro, Maria C.B.S.M.
• Is Part Of: Food chemistry. Volume 227(2017)
• Page Start: 166
• Page End: 172
• Publication Date: 2017-07-15
• Subjects: Perchlorate -- Pre-concentration -- Vegetable samples -- Potentiometric sensor -- Continuous flow-system; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2017.01.088
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Polysiloxane crown ether column for the analysis of trace perchlorate in vegetables. Multi-commutated flow-analysis concept with potentiometric detection. Nanomolar perchlorate determination. Perchlorate as an environmental contaminant effectively monitored. Abstract: In this work, an expeditious method based on the multi-commutated flow-analysis concept with potentiometric detection is proposed to perform determinations of the emergent contaminant perchlorate in vegetable matrices down to nanomolar concentration. To accomplish the task, a tubular shaped potentiometric sensor selective to perchlorate ion was constructed with a PVC membrane containing 12 mmol/kg of the polyamine bisnaphthalimidopropyl-4, 4′-diaminodiphenylmethane and 2-nitrophenyl phenyl ether 68% (w/w) as plasticizer casted on a conductive epoxy resin. Under optimal flow conditions, the sensor responded linearly in the concentration range of 6.3 × 10 −7 –1.0 × 10 −3 mol/L perchlorate. In order to extend the determinations to lower concentrations (4.6(±1.3) × 10 −10 mol/L perchlorate), a column packed with 70 mg of sodium 2, 5, 8, 11, 14-pentaoxa-1-silacyclotetradecane-polymer was coupled to the flow-system thus enabling prior pre-concentration of the perchlorate. The proposed procedure provides a simpler alternative for the determination of perchlorate in foods, nowadays only allowed by sophisticated and expensive equipment and laborious methods.