Emulsification based dispersive liquid microextraction prior to flame atomic absorption spectrometry for the sensitive determination of Cd(II) in water samples

Application of polysaccharide biopolymers as natural adsorbent in sample preparation

Preparing samples for analyses is perhaps the most important part to analyses. The varied functional groups present on the surface of biopolymers bestow them appropriate adsorption properties. Properties like biocompatibility, biodegradability, presence of different surface functional group, high porosity, considerable absorption capacity for water, the potential for modification, etc. turn biopolymers to promising candidates for varied applications. In addition, one of the most important parts of determination of an analyte in a matrix is sample preparation step and the efficiency of this step in solid phase extraction methods is largely dependent on the type of adsorbent used. Due to the unique properties of biopolymers they are considered an appropriate choice for using as sorbent in sample preparation methods that use from a solid adsorbent. Many review articles have been published on the application of diverse adsorbents in sample preparation methods, however despite the numerous advantages of biopolymers mentioned; review articles in this field are very few. Thus, in this paper we review the reports in different areas of sample preparation that use polysaccharides-based biopolymers as sorbents for extraction and determination of diverse organic and inorganic analytes.

Rapid photodegradation and detection of zolpidem over β-SnWO4 and α-SnWO4 nanoparticles: optimization and mechanism

We reported the tin (II) tungstate nanoparticles as the photocatalyst and sensor modifier that were synthesized via chemical precipitation reaction and optimized thru the Taguchi design method. The method predicted the best synthesis conditions that led to smaller particles and desired morphologies. Different techniques were used to characterize the chemical structure, morphology, and purity of the nanoparticles. The photocatalytic behavior of different crystalline forms of the SnWO₄ nanoparticles (α and β) was considered by photodegradation of methylene orange and zolpidem under UV light irradiation, while the average size of β-SnWO₄ and α-SnWO₄ nanoparticles prepared in optimum conditions is about 17 nm and 20 nm, respectively. Efficiencies of degradation of methyl orange and zolpidem on β-SnWO₄, in the presence of UV irradiation, were 93% and 98% and in the presence of α-SnWO₄ were 73% and 82% after 2100 s, respectively. Voltammetric sensing of zolpidem was designed by modification of carbon paste electrode via β-SnWO₄ nanoparticles and investigated for determination of the drug in aqueous solution.

A novel application of carbon dots for colorimetric determination of fenitrothion insecticide based on the microextraction method

In this work, the intrinsic colorimetric property of carbon dots (CDs) was utilized for the determination of fenitrothion by applying dispersive liquid-liquid microextraction (DLLME) method. Label free CDs are extracted into carbon tetrachloride via assistance of trioctylmethylammonium chloride (Aliquat 336), which also acts as a disperser agent in this technique. The enriched CDs show an absorption signal at 365nm, which increases in the presence of fenitrothion. The absorbance increase of CDs in organic phase was used as an analytical signal for the determination of fenitrothion. The synthesized CDs were characterized by UV-visible, fluorescence, Fourier transform infrared (FT-IR) and transmission electron microscopic (TEM). Under the optimized conditions, beer's law was obeyed in the range of 1.0-250.0ngmL^-1 of fenitrothion with the limit of detection for fenitrothion was 0.2ngmL^-1. The relative standard deviation for eight replicate measurements of fenitrothion at concentrations of 25 and 100ngmL^-1 were calculated to be 1.5 and 3.7%, respectively. The proposed method was successfully applied in the determination of fenitrothion in water samples with satisfactory results.

Comparison study on separation of morin: ultrasound assisted molecularly imprinted polymeric nanoparticles-solid phase extractionversussolidification of floating organic-drop assisted dispersive liquid–liquid microextraction

A comparison study between SPE-MIP-NPs and SFOD-DLLME was presented for separation and preconcentration of morin from aqueous media.

Simultaneous determination of ultra-low traces of lead and cadmium in food and environmental samples using dispersive solid-phase extraction (DSPE) combined with ultrasound-assisted emulsification microextraction based on the solidification of floating organic drop (UAEME-SFO) followed by GFAAS

Dispersive solid-phase extraction (DSPE) combined with ultrasound-assisted emulsification microextraction (UAEME) for determination of lead and cadmium in food and environmental samples prior to GFAAS.

Optimization of Emulsification-based Liquid Phase Microextraction of Chromium in Seawater of Chabahar Bay for its Speciation by High-Performance Liquid Chromatography

After complexation of Cr(III) and Cr(VI) species with diethyldithiocarbamate (0.2 mmol/L), effective parameters of emulsification-based dispersive liquid microextraction procedure was optimized for its preconcentration in artificial seawater. Triton X-305 as the emulsifying disperser and mixture of the chloroform and carbon tetrachloride as the extraction solvents show a better behavior at sample pH of 6.5. The method was applied for extraction and UV detection (λ = 254 nm) of chromium species of the Chabahar Bay seawater prior to high-performance liquid chromatography (conditions: C18, methanol: acetic acid solution 2% v (85:15), flow rate of 0.8 mL min^-1). Characteristics of the method such as enrichment factor (210 and 228), linear range (10-300 µg L^-1), limit of detection (0.017 and 0.597 µg L^-1) and repeatability, (N = 5, concentration of 100 µg L^-1 %relative standard deviation = 2.6% and 0.45%) were evaluated for Cr(III) and Cr(VI), respectively.