Application electrochemical sensor based on nanosheets G-C3N4/CPE by square-wave anodic stripping voltammetric for measure amounts of toxic tartrazine color residual in different drink and foodstuffs.

The present work describes a method (SWASV) techniques for measure of tartrazine color a harmful compound present in real samples, and the extremely harmful to humans and animals even at low concentrations using G-C3N4 nanosheets sensor. Here, we report the use of an electrochemical approach for analytical determination of toxic tartrazine that takes 150 s. The calibration curve was linear in range of the (0.02-18.0 µmol L-1). The current response was linearly proportional to the tartrazine concentration with a R2∼ 0.999. We demonstrated a sensitivity a limit of detection of (0.022 µmol L-1). Finally, sensor nanosheets G-C3N4/CPE introduced to measure toxic tartrazine in different drink and foodstuff samples was used and the chemical nanosheets G-C3N4/CPE sensor made it possible as an excellent sensor with reproducibility for determination other samples.

Enhanced fluorescent sensing probe via PbS quantum dots functionalized with gelatin for sensitive determination of toxic bentazon in water samples.

Fluorescent chemical sensors to detect materials, by increasing fluorescence emission and absorption or by shutting down, because they are nondestructive, the ability to show decomposed concentrations, fast response, high accuracy have been considered and used. In this research, a chemical sensor was synthesized PbS functionalized with gelatin quantum dots for the determination of toxic bentazon (BTZN) one of the most problematic pesticides polluting in water samples, and extremely harmful to humans and animals even at low concentrations. The calibration curve was linear in the range of (0.05 to 200.0 ng mL-1). The current response was linearly proportional to the BTZN concentration with a R2∼ 0.999. The standard deviation of less than (3%), and detection limits (3S/m) of the method (0.5 ng mL-1, in time 50 s, 325 nm) were obtained for sensor level response PbS Quantum Dot-Gelatin nanocomposites sensor with (99%) which is below the U.S. Health Advisory level. The observed outcomes confirmed the suitability recovery and a very low detection limit for measuring the BTZN. The method fluorometric introduced to measure BTZN in water samples was used and can be used for in different intricate matrices, the chemical PbS Quantum Dot-Gelatin nanocomposites sensor made it possible as an excellent sensor with good reproducibility.

Resonance Rayleigh scattering method for determination of 2-mercaptobenzothiazole using gold nanoparticles probe.

A sensitive, simple and novel method was developed to determine 2-mercaptobenzothiazole (2MBT) in water samples. This method was based on the interaction between gold nanoparticles (AuNPs) and 2MBT followed by increasing of the resonance Rayleigh scattering (RRS) intensity of nanoparticles. The change in RRS intensity (ΔIRRS) was linearly correlated to the concentration of 2MBT over the ranges of 5.0-100.0 and 100.0-300.0 µg L(-1). 2MBT can be measured in a short time (5 min) without any complicated or time-consuming sample pretreatment process. Parameters that affect the RRS intensities such as pH, concentration of AuNPs, standing time, electrolyte concentration, and coexisting substances were systematically investigated and optimized. Interference tests showed that the developed method has a very good selectivity and could be used conveniently for determination of 2MBT. The limit of detection (LOD) and limit of quantification (LOQ) were 1.0 and 3.0 µg L(-1), respectively. Relative standard deviations (RSD) for 20.0 and 80.0 µg L(-1) of 2MBT were 1.1 and 2.3, respectively. Possible mechanisms for the RRS changes of AuNPs in the presence of 2MBT were discussed and the method was successfully applied for the analysis of real water samples.

Determination of thiram using gold nanoparticles and Resonance Rayleigh scattering method.

A sensitive, simple and novel method was developed to determine thiram fungicide in water and plant samples. This method was based on the interaction between gold nanoparticles (AuNPs) and thiram fungicide followed by increasing of the Resonance Rayleigh scattering (RRS) intensity of nanoparticles. The change in RRS intensity (∆IRRS) was linearly correlated to the concentration of thiram over the range of 1.0-200.0µgL(-1). Thiram can be measured in a short time (4min) without any complicated or time-consuming sample pretreatment process. Parameters that affect the RRS intensities such as pH, concentration of AuNPs, standing time, electrolyte concentration, and coexisting substances were systematically investigated and optimized. Interference tests showed that the developed method has a very good selectivity and could be used conveniently for the determination of thiram. The limit of detection (LOD) and limit of quantification (LOQ) were 0.3 and 1.0µg L(-1), respectively. Relative standard deviations (RSD) for 20.0 and 80.0µg L(-1) of thiram were 3.0 and 1.1, respectively. Possible mechanisms for the RRS changes of AuNPs in the presence of thiram were discussed and the method was successfully applied for the analysis of spiked real water samples and fresh plant samples such as tomato and cucumber.

Sodium dodecyl sulfate coated poly (vinyl) chloride: an alternative support for solid phase extraction of some transition and heavy metals.

A simple and relatively fast approach for developing a solid phase extraction has been described and used for determination of trace quantities of some heavy and transition metal ions with sodium dodecyl sulfate (SDS)-coated poly vinyl chloride (PVC) modified with bis(2-hydroxyacetophenone)-1,4-butanediimine (BHABDI) ligand. The adsorbed ions were stripped from the solid phase by 10 mL of 3M nitric acid as eluent. The eluting solution was analyzed for metals content (cadmium, chromium, cobalt, copper, lead and zinc) by flame atomic absorption spectrometry (FAAS). The main factors such as pH, amount of ligand and PVC, amount and type of surfactant, and condition of eluting solutions on the sorption recovery of metal ions have been investigated in detail. The relative standard deviation was found in the range of 1.0-3.2% for 0.2 microg mL(-1)of metals ions. After optimization of the extraction condition and the instrumental parameters, a detection limit was found to be in the range of 1.2-3.1 microg L(-1), with enrichment factor of 50 was achieved. The method was successfully applied for the determination of these metals contents in real samples with satisfactory results.