The application of Na-Bi MOF as a heterometallic coordination polymer and 2,2-dimethoxypropane as an in-situ-generating ternary solvent for the extraction and preconcentration of some phthalate and adipate esters from tap, well, surface, and river water samples

Abstract

In this study, the first-ever attempt was done to apply a heterometallic metal–organic framework (MOF) called Na-Bi MOF for the extraction and preconcentration of some phthalate and adipate esters. Also for the first time, 2,2-dimethoxypropane was adopted as an efficient in-situ generating ternary solvent for the desorption aim. Diverse real samples including tap, well, surface, and river waters underwent the developed extraction procedure. For performing the process of extraction, only 5 mg of Na-Bi MOF was added into a sodium sulfate-enriched aqueous solution containing the target compounds and vortexed. So, the analytes were adsorbed onto the MOF particles. Centrifugation separated the analyte-loaded MOF from the aqueous solution. The MOF was treated with only 500 µL of 2,2-dimethoxypropane. By centrifugation, the organic phase was separated and subjected to evaporation using a gas splitter device. After the complete evaporation of the organic phase, only 5 µL of 1,2-dibromoethane was applied for the elution of the inner perimeter of the conical bottom glass test tube by vortexing. Eventually, two microliters of the organic phase were injected into a gas chromatograph equipped with flame ionization detection. High enrichment factors (520–800), satisfactory extraction recoveries (52–80 %), low limits of detection and quantification (0.66–1.20 and 2.18–3.97 µg/L, respectively), favorable relative recoveries without dilution (86–117 %), wide linear ranges (3.97–500 µg/L), and high coefficients of determination (0.9903–0.9944) were recorded for the developed method. Low amount use of the MOF and organic solvents, diversity of real samples, no need for dilution, and short chromatographic run (a quarter) are the highlights of the developed method.