SPE and determination by FAAS of heavy metals using a new synthesized polymer resin in various water and dried vegetables samples

Insights into brewed tea waste as a green and low-priced adsorbent for solid-phase extraction of Cd(II) ions: isotherm, kinetic, and artificial neural network approach

In the present research, brewed tea waste (BTW) was utilized as a green, low-priced, and abundant adsorbent for separation/preconcentration of Cd(II) ions through solid-phase extraction method from water and foods for the first time. BTW was applied as a natural adsorbent, without using any chelating agent to bind Cd(II) ions or any chemical reagent for its modification. A three-layer artificial neural network model using backpropagation algorithm was utilized to explicate a prediction model for the extraction performance of Cd(II) ions by selecting the input parameters as solution pH, quantity of BTW, sample volume, eluent concentration and volume, and equilibrium time for desorption. The preconcentration factor, relative standard deviation, and detection limit were attained as 100, 3.03%, and 0.56 µg L−1, respectively. It was decided that the Langmuir isotherm model is acceptable to characterize the retention of Cd(II) ions on BTW. This result pointed out that the active binding sites on the BTW surface are homogeneously distributed. Adsorption capacity of BTW was achieved as 41.5 mg g−1 which is higher than several expensive and difficult-to-prepare adsorbents. Adsorption kinetics was elucidated by pseudo-second order kinetic model. After confirmed the accuracy of the method with spike/recovery studies, it was employed for Cd(II) determination in water (stream and sea water) and food (eggplant, lettuce, parsley, apple, and apricot) samples with high accuracy. The inferences of the study proved that the BTW offers a magnificent application prospect in the extraction of Cd(II) ions.

A synthesized ternary polymer composite and its use for SPE of trace metals in Coffee, tea and legumes

A new synthesized ternary polymer composite, polystyrene/polyacrylonitrile/polyindole (PSt/PAN/PIN), was used as an adsorbent. The structure of synthesized composite was supported by FTIR, BET, X-RD, TGA, SEM and AFM technique. A SPE method with synthesized composite was developed for the preconcentration of chromium, copper, iron, manganese, lead and zinc ions. The adsorption capacity were found in the range of 37.4-56.7 mg g^-1. Under the best conditions, the preconcentration factor of method was found as 100. Relative standard deviation was found at ≤ 3.3% (n = 11). The detection limits of analytes were obtained as: 0.9 μg L^-1 for Cr(III), 1.2 μg L^-1 for Cu(II), 2.0 μg L^-1 for Fe(III), 1.4 μg L^-1 for Mn(II), 0.9 μg L^-1 for Pb(II) and 2.0 µg L^-1 for Zn(II). Firstly, this SPE method was applied to certified reference material, and than coffee, tea, legumes. The trace metals was analyzed by flame atomic absorption spectrometry.

Preconcentration of Lead in Blood and Urine Samples Among Bladder Cancer Patients Using Mesoporous Strontium Titanate Nanoparticles

In this work, mesoporous strontium titanate nanoparticles (SrTiO₃ NPs) were synthesized through a single-step combustion process and were characterized by FT-IR, XRD, SEM-EDX, and TEM. The effects of main parameters that may influence the extraction process (i.e., pH, sorbent amount, time of extraction, eluting agent, and the presence concomitant ions) were investigated. The optimum extraction was achieved at pH 6, 50 mg of sorbent, 20-min shaking time, and 4.0 mL of 0.1 mol L^-1 thiourea as desorption agent. Under these conditions, the maximum adsorption capacity was 155.6 mg g^-1 with a preconcentration factor of 250 (for a 1000 mL sample solution). The calibration graph was linear up to 1000 μg L^-1 and the limit of detection was 1.75 μg L^-1. The precision (as relative standard deviation) was 2.53% (n = 10). The procedure was employed for the preconcentration of Pb²⁺ from blood and urine samples of bladder cancer patients before its determination by FAAS.