Aptamer functionalized magnetic metal-organic framework MIL-101(Cr)-NH2 for specific extraction of acetamiprid from fruit juice and water samples.

An aptamer-functionalized magnetic metal-organic framework (MMIL-Apt) was prepared and used for selective magnetic solid phase extraction (MSPE) of acetamiprid. To examine the morphology of the adsorbent, different techniques such as FT-IR spectrometry, vibrating sample magnetometery, TEM, FE-SEM and EDS were employed. The MMIL-Apt combines the advantages of aptamers and magnetic MMIL-101(Cr)-NH2 such as specific recognition of analyte, good stability and fast separation. To reach high MSPE recovery, various extraction parameters were examined and optimized. The limit of detection (LOD) was reached 0.0018 µg L-1. This method showed perfect linearity (0.006-1800 µg L-1) with a good correlation coefficient (R2 = 0.9993). The relative standard deviations for intra- and inter-day analyses were 3.61% and 8.10%. The extraction recoveries in water samples and fruit juices were obtained from 80.20% to 101.81 %. The results indicated the modified sorbent is practically applicable for the specific extraction of trace amounts of acetamiprid from different matrices.

Metal-organic framework MIL101 (Cr)-NH2 functionalized magnetic graphene oxide for ultrasonic-assisted magnetic solid phase extraction of neonicotinoid insecticides from fruit and water samples.

In this work, a magnetic nanocomposite composed of graphene oxide (GO), silica-coated cobalt ferrite (CoFe2O4@SiO2) nanoparticles and amino-functionalized metal-organic framework (MIL 101 (Cr)-NH2) was fabricated and employed for ultrasonic-assisted magnetic solid phase extraction (UA-MSPE) of neonicotinoid insecticides. Various techniques such as Fourier transform infrared (FT-IR) spectrometry, vibrating sample magnetometry (VSM), energy-dispersive X-ray spectroscopy (EDS) and field emission scanning electron microscope (FE-SEM) measurements were executed to investigate features and morphology of the adsorbent. The magnetic graphene oxide functionalized MIL-101 (Cr)-NH2 (MGO/MIL) combines the advantages of magnetic GO and MIL 101(Cr)-NH2 such as excellent thermal and chemical stability, high surface area, accessible coordinative unsaturated sites, sufficient stability in aqueous solutions and rapid and easy separation from the solution. Some of the important extraction factors such as type and volume of desorption solvent, desorption time, salt concentration, adsorbent amount, pH and extraction time were investigated in detail to achieve high MSPE recovery. In optimal condition, the limits of detection (LODs) for Acetamiprid and Imidacloprid were achieved 0.022 and 0.019 ng mL-1, respectively. Good determination coefficients (R2 more than 0.9990) with satisfactory linearity in the range of 0.064-3500 ng mL-1 were found for this method. The relative standard deviations for intra- and inter-day analyses were in the range of 3.93-4.56% and 7.80-8.50%, respectively. The method was successfully used for analyzing of neonicotinoid insecticides in water and fruit samples and acceptable recoveries from 82.13% to 102.27% were obtained. The results indicated that the nanocomposite is feasible for the adsorption of trace amounts of the target analytes from the fruit and water samples.

Aptamer functionalized magnetic nanoparticles for effective extraction of ultratrace amounts of aflatoxin M1 prior its determination by HPLC.

Aptamers, due to the inherently high selectivity towards target analytes, are promising candidate for surface modification of the nanoparticles. Therefore, aptamer-functionalized magnetic nanoparticles (AMNPs) was prepared and used to develop a magnetic solid-phase extraction procedure for clean-up of milk and dairy products samples before measuring the aflatoxin M1 (AFM1) contents by the high-performance liquid chromatography. The prepared sorbent was characterized by different instrumental methods such as FT-IR, FESEM, TEM, EDX and AGFM. The AMNPs was used in extraction and pre-concentration of ultratrace amounts AFM1 from local milk samples. The amount of sorbent, elution volume, extraction time, and salt addition were optimized. Based on the results, calibration plot is linear over the 0.3 to 1 ng·L-1 and 5 to 50 ng·L-1 AFM1 concentration ranges. The limits of detection of the developed method were obtained 0.2 ng·L-1 which is the smallest value that has been reported up to now. The results show that this new superior sorbent has a large potential to simplify the complex matrix of the samples and can used for detection, preconcentration and accurate determination of ultratrace amounts of the AFM1 from milk and dairy products.

Corrigendum to "Exposure assessment of Bisphenol A intake from polymeric babybottles in formula-fed infants aged less than one year" [Toxicology Reports 2 (2015) 1273-1280].

[This corrects the article DOI: 10.1016/j.toxrep.2015.09.002.].

Exposure assessment of Bisphenol A intake from polymeric baby bottles in formula-fed infants aged less than one year.

BisphenolA (BPA) or 2,2-bis(4-hydroxyphenyl)propanepresent in polycarbonate baby bottles may have harmful effects for formula-fed infants. This study evaluated the risks associated with exposure to BPA among Iranian formula-fed infants in an urban society in Isfahan. New and used baby bottles (n = 7 and 8, respectively) as well as BPA-free marked bottles (n = 2) were collected from a retail outlet, and leaching of BPA was examined by conducting a migration test. Concentrations of BPA released from the new and used baby bottles were in the range of 0.49â¿¿8.58 and 0.63â¿¿2.47 µg/l, respectively. Next, probabilistic exposure estimation was performed. In all, 200 mothers registered with 11 health centres in Isfahan were interviewed. Data on feeding pattern, washing and sterilization practices, bottles types and manufacturers as well as the sex and weight of the infants were collected using a questionnaire. The results showed that majority of the surveyed infants were exposed to 0.1â¿¿0.3 µg/kg body weight (bw)/d of BPA, which corresponded to approximately 2â¿¿7.5% of the defined t-TDI (4 µg/kgbw/d). These results suggested that the risk of the adverse effects caused by exposure to BPA was very low in formula-fed Iranian infants even in the worst-case scenario.

Fractionation of Eremurus spectabilis fructans by ethanol: Box-Behnken design and principal component analysis.

The fructans, inulin and oligofructose, are known to exert many food and pharmaceutical applications and are widely used in functional foods throughout the world for their nutritional and techno-functional properties. In the present study, the Box-Behnken design was used to determine the optimal conditions for fructan precipitation from Eremurus spectabilis root powder (Serish) by adding ethanol that gave the maximum yield. Ethanol-to-syrup (E/S) ratio (2:1-15:1), precipitation temperature (30-60°C) and syrup concentration (10-40°B) were considered variables of fructan precipitation. The most compatible model among mean, linear and quadratic expressions was fitted to each response and the regression coefficients were determined using least square method. There was a good agreement between the experimental data and their predicted counterparts. The optimum conditions for fractionating fructan composition of Serish by ethanol were estimated to be E/S ratio of 8.56, temperature of 23.51°C and initial syrup concentration of 40°B. Precipitation under these optimized conditions achieved the best yield (85.81%), average chain length (12.92) and purity (80.18%). In addition, principal component analysis (PCA) allowed discriminating among precipitated fructan specialties.

Study on solid-phase extraction and flame atomic absorption spectrometry for the selective determination of cadmium in water and plant samples with modified clinoptilolite.

A sensitive, simple separation and solid-phase procedure, which is sorption and desorption of cadmium on modified clinoptilolite zeolite (with surfactant and neothorine), for preconcentration of cadmium prior to analysis by FAAS is described. The sorbent has exhibited good sorption potential for cadmium at pH 5. Cadmium was eluted from the column by nitric acid which resulted in preconcentration factor of 160. Thermodynamic behaviors for the process are investigated and adsorption process is interpreted in term of Freundlich equation. A detection limit of 0.015 ng mL(-1) was obtained and it is shown that calibration curve is linear from 0.01 to 4.0 microg mL(-1) in the final solution. Furthermore, the effects of various parameters such as pH, flow rate of the sample and eluent solution were studied. This method was successfully applied for determination of cadmium in various plant and real water samples.

Determination of trace amounts of zinc by flame atomic absorption spectrometry after preconcentration with modified clinoptilolite zeolite.

Natural clinoptilolite was used as a sorbent material for solid-phase extraction and preconcentration of zinc. Clinoptilolite was first saturated with cadmium (II) and then modified with benzyldimethyltetradecylammonium chloride for increasing adsorption of 3-(2-arsenophenylazo)-4,5-dihydroxy-2,7-naphthalene disulfonic acid (neothorin). Zinc was quantitatively retained on the adsorbent by the column method in the pH range of 3.8-4.2 at a flow rate of 1 mL/min. It was eluted from the column with 5.0 mL 2 M nitric acid solution at a flow rate of 1 mL/min and determined by flame atomic absorption spectrometry at 213.9 nm. Zinc could be concentrated from a 0.03 microg/L solution with a preconcentration factor of 170. Relative standard deviation for 8 replicate determinations of 2.5 microg zinc in the final solution was 0.92%. The interference of a large number of anions and cations was studied in detail to optimize the conditions, and the method was successfully applied for determination of zinc in standard and real water samples.