Use of dispersive liquid–liquid microextraction for the determination of carbamates in juice samples by sweeping-micellar electrokinetic chromatography

Abstract

Dispersive liquid-liquid microextraction (DLLME) has been proposed for the extraction and preconcentration of 12 carbamate pesticides in juice samples, followed by their determination by micellar electrokinetic chromatography with diode-array detection. To improve sensitivity, an on-capillary sample concentration method based on sweeping has been developed. Also, separations were performed in an extended light path fused-silica capillary; the separation buffer consisted of 100 mM borate and 50 mM SDS (pH 9.0) with 5% acetonitrile. Samples were introduced by hydrodynamic injection, dissolved in the separation buffer, but free of micelles. Several parameters of the DLLME procedure (such as type and volume of extraction and dispersive solvents, pH, salt addition, and extraction time) were optimized. Recoveries obtained for fortified juice samples (banana, pineapple, and tomato) at three different concentration levels, ranged from 78% to 105%, with relative standard deviations lower than 9%. The limits of detection ranged from 1 to 7 μg l(-1). Moreover, the method is fast, simple, and environmentally friendly.

Ionic liquid based microextraction combined with derivatization for efficient enrichment/determination of asulam and sulfide

“…Compared with the presented asulam determination method, the methods in Table 5 show some disadvantages in the limit of detection, 1,4,5,7,8,12,37 linear dynamic range [3][4][5]10 , and the range of the sample analyzed. [1][2][3][4][5][6][7][8][9][10]12,37 Moreover, the analytical characteristics of the presented sulfide determination method were compared with the others as shown in Table 6. Compared with the presented sulfide enrichment/determination method, the others show some limitations in the limit of detection, 19,20,38−44 linear dynamic range, 20,42 and the range of the sample analyzed.…”

Separation and Preconcentration by Dispersive Liquid–Liquid Microextraction Procedure: Recent Applications

“…Pharmaceutical preparations [27] Separation and Preconcentration by DLLME 653 [68] Separation and Preconcentration by DLLME 655 Tap, lake and river waters [79] Clozapine, chlorpromazine Red wines [104] Separation and Preconcentration by DLLME 657 Table 1 continued Analyte Disperser solvent volume Waters [105] Hexanal and heptanal 50 lL Plants [113] Pesticides and metabolites 418 lL Juice samples [122] technique, an extraction solvent with a low density and low toxicity is employed, which could make the mass transfer as fast as DLLME. Moreover, the melting point (close to or below room temperature) of the extraction solvent makes the floating phase solid, making easier transfer of the floated droplet so that loss of the analytes can be avoided and the precision improved.…”

Salting-out assisted liquid–liquid extraction with the aid of experimental design for determination of benzimidazole fungicides in high salinity samples by high-performance liquid chromatography

“…Four benzimidazole fungicides standards of carbendazim (CBZ), fuberidazole (FBZ), thiophanate-methyl (TPM) and thiophanate (TP), derived from carbamic acid with chemical structure R-O-C(O)-N(CH 3 )-R 0 , where R is an alcohol, an oxime or a phenol, and R 0 is a hydrogen or a methyl group [1], were purchased from Sigma-Aldrich (Shanghai, China), and their chemical structures are shown in Fig. 1.…”

“…Benzimidazole fungicides are used worldwide as broad spectrum pesticides against insects, fungi and weeds on a wide variety of fruits, vegetables and other crops [1,2]. Although many public benefits have been realized by utilizing benzimidazole fungicides, their massive use in the last years has led into their accumulation in the environment, thus contaminating the water streams which cannot be disregarded.…”