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In the present study, a novel method based on fluconazole-functionalized magnetic silica nanoparticles as the adsorbent is introduced for the extraction of malachite green and crystal violet. The synthesized nanoparticles were characterized using SEM, EDX, XRD, FT-IR, and BET methods. The adsorbent were added to the sample solution containing 100.0 ng mL−1of each dye (pH 5.0); then, the mixture was agitated at room temperature for 20.0 min. The supernatant was poured, and then, the isolated nanoparticles were eluted with methanol to desorb the adsorbed dyes. Different parameters were investigated and optimized to achieve effective extraction and preconcentration of the target dyes. Limits of detection and limits of quantification for malachite green and crystal violet under optimum conditions changed in the range of 2.82–3.27 ng mL−1and 9.42–10.91 ng mL−1, respectively. Preconcentration factor and relative standard deviation for five repetitions of each dye were computed to be 188 and 4.77–4.17%, respectively. Finally, the mentioned dyes were extracted and determined using the proposed method from environmental aqueous samples. The recoveries range for malachite green and crystal violet were in 88–96%.

In this study, a new method based on electromembrane extraction (EME) followed by corona discharge ion mobility spectrometry (CD-IMS) was used for preconcentration and quantification of malachite green in water samples. In the EME procedure, the charged malachite green migrated into the supported liquid membrane (SLM) under an applied potential. The extraction efficiency of malachite green was assessed based on two phase EME under effective parameters including applied voltage, extraction time, pH of the sample solution, stirring rate, and salt addition in the sample solution. The analytical performance of the developed EME method was studied under the optimum extraction condition. The dynamic linear range and low limit of detection of the EME method were 5–250 ng mL−1and 1.5 ng mL−1, respectively. The preconcentration factor of 150 and the RSD% of 3.8–7.6% were also achieved using EME method. Finally, the proposed method was successfully tested for the extraction and analysis of malachite green in different water samples.

A dispersive solid-phase extraction procedure using molybdenum disulfide as an adsorbent was developed for pretreatment and preconcentration of low quantity of ibuprofen in natural samples prior to enantioseparation. The chiral separation was carried out by vancomycin-mediated capillary electrophoresis coupled with UV detector. The effect of the main factors on the extraction recovery and enantioselective resolution was investigated using a central composite design. The best enantioseparation of ibuprofen was achieved on an uncoated capillary at 20 °C using phosphate buffer (pH 6.5) containing 1 mM vancomycin and 20 kV applied voltage. The optimum condition of the dispersive solid-phase extraction was obtained at the sample solution with pH 4.0 containing 1.4 M NaCl, 0.12 g adsorbent, 10 min adsorption time, 25 °C adsorption temperature, 1 mL the elution solvent (acetone-0.25 M NaOH (aq) (2:1 (v v−1)), 5 min desorption time, 50 °C desorption temperature, and the stirring speed of 900 rpm for adsorption and desorption steps. Good values of linearity range (0.125–5 µg mL−1, R2= 0.999), preconcentration factor (33.4), precision (less than 2.3%), and recovery (93.2%) were achieved. The limit of detection and quantification of, respectively, 0.025 and 0.070 μg mL−1was provided, which enabled a satisfactory trace determination of ibuprofen in urban water and human urine samples.

In this paper, a novel solid phase microextraction fiber based on Co3O4quantum dot incorporated polyacrylamide-co-ethylene glycol dimethacrylate followed by corona discharge ion mobility spectrometry is presented for the trace determination of organophosphorus pesticides in environmental water samples. Ion mobility spectrometry is a comparatively inexpensive, well-known, robust, and easy to operate analytical instrument. This combination would provide a low-cost, fast, selective, and sensitive quantitative system for detection of organophosphorus pesticides. In order to obtain the best extraction efficiency, the optimization of parameters affecting this method was carried out. After optimization, a solution pH of 7.0, extraction temperature of 60 °C, adsorption temperature of 260 °C, extraction time of 30 min, stirring speed of 750 rpm, and ionic strength of 10% w/w were obtained. Consequently, the presented method showed low limits of detection (0.3–0.6 ng mL−1), excellent enrichment factors (PF = 221–263), good linearity (R2> 0.995), and repeatabilities (intra-day: 3.4 to 4.8%) and (inter-day: 4.7 to 6.1%). The reproducibility (RSD% of fiber to fiber) was also investigated by analyzing three as-prepared fibers under the same conditions and was found to be less than 7.6%. Finally, the developed fiber was used for determination of organophosphorus pesticides in the field samples.