Correction: Extraction of diazinon, haloxyfop-R-methyl, hexaconazole, diniconazole, and triticonazole in cheese samples using a ferrofluid based liquid phase extraction method prior to gas chromatography.

Correction for 'Extraction of diazinon, haloxyfop-R-methyl, hexaconazole, diniconazole, and triticonazole in cheese samples using a ferrofluid based liquid phase extraction method prior to gas chromatography' by Mahdi Rouhi et al., Anal. Methods, 2023, 15, 3043-3050, https://doi.org/10.1039/D3AY00160A.

A Simple and Novel Sensor for the Determination of Acetamiprid Based on Its Reducing Effect on the Chemiluminescence of S, N-CQDs in CH3CN-H2O2 System.

A simple and novel method for the determination of acetamiprid in water samples is suggested. The method is based on the reducing effect of acetamiprid on the chemiluminescence intensity of new sulfur and nitrogen co-doped carbon dots (S, N-CQDs) in an acetonitrile-hydrogen peroxide (CH3CN-H2O2) system. The possible mechanism was investigated, and it was found that S, N-CQDs react with (1O2)2*, produced from the CH3CN-H2O2 reaction, leading to excited state S, N-CQDs, which deactivate to the ground state by photon emission. Acetamiprid diminishes the chemiluminescence (CL) intensity by competing with S, N-CQDs. The CL intensity reduction is proportional to the concentration of acetamiprid. S, N-CQDs were easily prepared by a hydrothermal method. Under the optimal conditions, a linear range of 2.5 - 25.0 µg L-1 with a detection limit (3σ) of 0.4 µg L-1 was obtained. This method was successfully applied to the determination of trace amounts of residual pesticides in water samples.

A Highly Efficient Chemiluminescence System Based on an Enhancing Effect of Ag Nanoclusters/Graphene Quantum Dots Mixture for Ultrasensitive Detection of Rabeprazole.

Herein, an efficient chemiluminescence (CL) reaction with a high emission intensity is reported based on a synergistic improving effect of silver nanoclusters (AgNCs) and graphene quantum dots (GQDs). First, the syntheses of AgNCs and GQDs were simply performed by the chemical reducing of AgNO3 and a thermal treatment of glucose, respectively. After the characterization steps, the beneficial behavior of the prepared nanomaterial was investigated in CL systems. The oxidation reaction of KMnO4-rhodamine B produced weak CL emission. However, the presence of AgNCs and GQDs led to a synergetic enhancing effect, and thus higher emission was obtained. A possible mechanism was investigated for this effect using absorption and fluorescence experiments. Furthermore, rabeprazole showed a relatively selective enhancing impact on the CL emission. The CL intensity was linearly increased in the rabeprazole concentration range of 4 - 133 ng mL-1 with a detection limit (3Sb/m) of 1.1 ng mL-1. The developed CL method was utilized for the measurement of Rbp in biological samples with acceptable precision and accuracy.

Ultrasensitive chemiluminescence assay for cimetidine detection based on the synergistic improving effect of Au nanoclusters and graphene quantum dots.

A novel and sensitive chemiluminescence (CL) procedure based on the synergetic catalytic effects of gold nanoclusters (Au NCs) and graphene quantum dots (GQDs) was developed for the reliable measurement of cimetidine (CM). The initial experiments showed that the KMnO4 -based oxidation of alkaline rhodamine B (RhoB) generated a very weak CL emission, which was intensively enhanced in the simultaneous presence of Au NCs and GQDs. CL intermediates can be adsorbed and gathered on the surface of Au NCs, becoming more stable. GQDs participate in the energy transferring processes and facilitate them. These improving effects were simultaneously obtained by adding both Au NCs and GQDs into the RhoB-KMnO4 reaction. Consequently, the increasing effect of the Au NCs/GQDs mixture was more than that of pure Au NCs or GQDs, and a new nano-assisted powerful CL system was achieved. Furthermore, a marked quenching in the emission of the introduced CL system was observed in the presence of CM, so the system was examined to design a sensitive sensor for CM. After optimization of influencing parameters, the linear lessening in CL emission intensity of KMnO4 -RhoB-Au NCs/GQDs was verified for CM concentrations in the range 0.8-200 ng ml-1 . The limit of detection (3Sb /m) was 0.3 ng ml-1 . Despite being a simple CL method, good sensitivity was obtained for CM detection with reliable results for CM determination in human urine samples.

Rhodamine B Chemiluminescence Improved by Mimetic AuCu Alloy Nanoclusters and Ultrasensitive Measurement of H2O2, Glucose and Xanthine.

The less stability and robustness, high-cost preparation and maintenance of natural enzymes, especially horseradish peroxidase (HRP), challenge researchers to introduce effective alternatives for their wide applications. Herein, the peroxidase-like activity of AuCu bimetal nanoclusters (AuCu NCs) was investigated in the rhodamine B-H2O2 chemiluminescence (CL) system. AuCu NCs could effectively catalyzed the CL reaction, and a high intensive emission intensity was obtained. A comprehensive study was implemented to examine the effects of different stabilizing ligands and Au/Cu ratios on the catalytic activity of obtained NCs. Comparison experiments were also expanded to include Au and Cu nanoparticles with different sizes, too. The results verified the superior catalytic activity of penicillamine-stabilized AuCu bimetal NCs containing 50% cu atoms. Finally, the analytical application of the introduced CL system showed great sensitivity for H2O2 detection, with a detection limit of 0.13 nM. Moreover, the developed CL method was able to measure glucose and xanthine over wide concentration ranges of 0.1 - 400 and 0.1 - 200 µM, respectively. The method also indicated satisfactory reliability, confirmed by standard reference materials.

Ag Nanoparticles-enhanced Fluorescence of Terbium-Deferasirox Complexes for the Highly Sensitive Determination of Deferasirox.

We describe the effect of different sized gold and silver nanoparticles on the terbium sensitized fluorescence of deferasirox. It is indicated that silver nanostructures, especially 18 nm Ag nanoparticles (AgNPs), have a remarkable amplifying effect compared to Au nanoparticles. Based on this observation, a highly sensitive and selective method was developed for the determination of deferasirox. Effects of various parameters like AgNPs and Tb(3+) concentration and pH of media were investigated. Under the optimal conditions, a calibration curve was plotted as the fluorescence intensities versus the concentration of deferasirox in the range of 0.1 to 200 nmol L(-1), and detection limit of 0.03 nmol L(-1) was obtained. The method has good linearity, recovery, reproducibility and sensitivity, and was satisfactorily applied for the determination of deferasirox in urine and pharmaceutical samples.

Potassium permanganate-glutaraldehyde chemiluminescence system catalyzed by gold nanoprisms toward selective determination of fluoride.

Gold and silver nanoparticles (NPs) are shown to exert a positive effect on the chemiluminescence (CL) reaction of permanganate aldehydes. Interestingly, between various shapes examined, Au nanoprisms have the highest beneficial effect. This effect is even more notable in the presence of sodium dodecyl sulfate (SDS) surfactant. UV-vis spectra and transmission electron microscopy were used to characterize the NP shapes and sizes. Furthermore, it was observed that iron(III) ions can slightly increase CL emission of this system. This intensification is very effective in the presence of fluoride ions (F(-)). These observations form the basis of the method for the high sensitive determination of F(-) in the 6-1200 nmol L(-1) concentration range, with a detection limit of 2.1 nmol L(-1). The proposed method has good precision and was satisfactorily used in the selective determination of low concentrations of fluoride ion in real samples.

Highly Sensitive Determination of Ethylenediaminetetraacetic Acid Using a Permanganate Chemiluminescence System Catalyzed by Gold Nanoparticles.

A sensitive and selective chemiluminescence method was developed to determine ethylenediaminetetraacetic acid (EDTA) in water samples. It was observed that gold nanoparticles (AuNPs) catalyzed chemiluminescence (CL) reactions of permanganate-aldehydes which underwent an enhancement effect in the presence of iron(III) ions (Fe(3+)). This effect is more remarkable in the presence of EDTA, and a highly intensive CL emission is created in proportion to the EDTA concentration. These observations form the basis of the method for the high sensitive determination of EDTA in the 0.83 - 167 nmol L(-1) concentration range, with a detection limit of 0.25 nmol L(-1). The relative standard deviations for five repeated measurements of 5, 40 and 140 nmol L(-1) EDTA were 1.14, 2.48 and 0.65%, respectively. The method has good selectivity toward EDTA, and there are no interferences from other ions. The offered method has good precision, and was satisfactorily used for the sensitive determination of EDTA in water samples.

Determination of Hg(II) ions in sea food samples after extraction and preconcentration by novel Fe3O 4@SiO 2@polythiophene magnetic nanocomposite.

This work describes a novel Fe3O4@SiO2@polythiophene magnetic nanocomposite and its application in the preconcentration of Hg(II) ions. The parameters affecting the preconcentration procedure were opted by a Box-Behnken design through response surface methodology. Three factors (uptake time, magnetic nanosorbent amount, and pH of sample) were selected as the main factors affecting the sorption step, while four variables (type, volume and concentration of the eluent as well as the elution time) were selected as main factors in the optimization study of the elution step. Following the sorption and elution of Hg(II), it was quantified by cold vapor atomic absorption spectrometry. Under the optimum condition, the limit of detection was 0.02 ng mL(-1) and all the relative standard deviations were less than 9.2 %. The obtained sorption capacity of this new sorbent was 59 mg g(-1). Finally, this nanocomposite was successfully applied to the rapid extraction of trace quantities of Hg(II) ions in sea food samples and satisfactory results were obtained.

Determination of mercury(II) ions in seafood samples after extraction and preconcentration by a novel functionalized magnetic metal-organic framework nanocomposite.

This work describes a novel functionalized magnetic metal-organic framework nanocomposite [(Fe3O4-2,5-dimercapto-1,3,4-thiadiazole)/metal-organic framework] and its application in the preconcentration of Hg(II) ions. The parameters affecting the preconcentration procedure were optimized by a Box-Behnken design through response surface methodology. Three variables (uptake time, magnetic nanosorbent amount, and pH value) were selected as the main factors affecting the sorption step, while four variables (type, volume, and concentration of the eluent; and elution time) were selected as main factors in the optimization study of the elution step. Following the sorption and elution of analytes, the ions were quantified by cold vapor atomic absorption spectrometry. Under the optimum conditions, the limit of detection was 0.01 ng/mL and all the relative standard deviations were less than 10%. The obtained sorption capacity (in mg/g) of this new sorbent was 124. Ultimately, this nanocomposite was successfully applied to the rapid extraction of trace quantities of Hg(II) ions in seafood samples and satisfactory results were obtained.

Determination of heavy metal ions in vegetable samples using a magnetic metal-organic framework nanocomposite sorbent.

This paper describes the synthesis and application of a novel magnetic metal-organic framework (MOF) [(Fe3O4-benzoyl isothiocyanate)/Cu3(benzene-1,3,5-tricarboxylate)2] to pre-concentrate trace amounts of Cd(II), Pb(II), Zn(II) and Cr(III) ions and their determination by flame atomic absorption spectrometry. A Box-Behnken design was used to find the parameters affecting the pre-concentration procedure through response surface methodology. Three factors including uptake time, amount of the magnetic sorbent and pH of the sample were selected as affecting factors in the sorption step, and four factors including type, volume and concentration of the eluent as well as the elution time were selected in the elution step for the optimisation study. The opted values were 30 mg, 10.1 min, 5.9, EDTA, 4.0 ml, 0.57 mol l(-1) EDTA solution and 13.0 min for the amount of the magnetic sorbent, uptake time, pH of the sample, type, volume, concentration of the eluent, and elution time, respectively. The limits of detection (LODs) were 0.12, 0.7, 0.16, and 0.4 ng ml(-1) for Cd(II), Pb(II), Zn(II) and Cr(III) ions, respectively. The relative standard deviations (RSDs) of the method were less than 7.2% for five separate batch experiments for the determination of 30 µg l(-1) of Cd(II), Pb(II), Zn(II) and Cr(III) ions. The sorption capacity of the [(Fe3O4-benzoyl isothiocyanate)/MOF] was 175 mg g(-1) for Cd(II), 168 mg g(-1) for Pb(II), 210 mg g(-1) for Zn(II) and 196 mg g(-1) for Cr(III). It was found that the magnetic MOF nanocomposite demonstrated a higher capacity compared with Fe3O4-benzoyl isothiocyanate. Finally, the magnetic MOF nanocomposite was successfully applied to the rapid extraction of trace amounts of the heavy metal ions from vegetable samples.

Application of 1-(2-pyridylazo)-2-naphthol-modified nanoporous silica as a technique in simultaneous trace monitoring and removal of toxic heavy metals in food and water samples.

Solid-phase extraction is one the most useful and efficient techniques for sample preparation, purification, cleanup, preconcentration, and determination of heavy metals at trace levels. In this paper, functionalized MCM-48 nanoporous silica with 1-(2-pyridylazo)-2-naphthol was applied for trace determination of copper, lead, cadmium, and nickel in water and seafood samples. The experimental conditions such as pH, sample and eluent flow rate, type, concentration and volume of the eluent, breakthrough volume, and effect of coexisting ions were optimized for efficient solid-phase extraction of trace heavy metals in different water and seafood samples. The content of solutions containing the mentioned heavy metals was determined by flame atomic absorption spectrometry (FAAS), and the limits of detection were 0.3, 0.4, 0.6, and 0.9 ng mL(-1) for cadmium, copper, nickel, and lead, respectively. Recoveries and precisions were >98.0 and <4%, respectively. The adsorption capacity of the modified nanoporous silica was 178 mg g(-1) for cadmium, 110 mg g(-1) for copper, 98 mg g(-1) for nickel, and 210 mg g(-1) for lead, respectively. The functionalized MCM-48 nanoporous silica with 1-(2-pyridylazo)-2-naphthol was characterized by thermogravimetry analysis (TGA), differential thermal analysis (DTA), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), elemental analysis (CHN), and N2 adsorption surface area measurement.

Application of mercapto ordered carbohydrate-derived porous carbons for trace detection of cadmium and copper ions in agricultural products.

In this paper, we have introduced nanoporous carbon modified with mercapto groups as a new solid-phase method for extraction of cadmium(II) and copper(II) ions. The modified nanoporous carbon sorbent was characterised by thermogravimetric analysis, differential thermal analysis, transmission electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction, and nitrogen adsorption surface area (BET) measurements. Effects of pH value, flow rates, type, concentration and volume of the eluent, breakthrough volume, and effect of other ions were studied. The experimental results show that simultaneous trace cadmium(II) and copper(II) ions can be quantitatively preconcentrated at pH 6.0 with recoveries >97%. Under optimised conditions, limits of detection are 0.04 and 0.09 ng mL(-1) for the ions of cadmium and copper respectively, and the precision of the method for analysis of cadmium and copper ions (5.0 µg of each target ions, N=8) are 2.4% and 2.1%, respectively. The obtained capacities of mercapto-nanoporous carbon were found to be 145 and 95 mg g(-1) for cadmium and copper ions, respectively. The accuracy of the proposed procedure was verified by analysing standard reference material. Finally, the introduced sorbent was successfully applied for trace determination of cadmium and copper ions in food samples.

A new spectrofluorimetric method for the determination of some tetracyclines based on their interfering effect on resonance fluorescence energy transfer.

A rapid, simple, inexpensive and highly sensitive spectrofluorimetric method was developed for the determination of trace amounts of some tetracyclines (TCs), namely tetracycline hydrochloride (TCH), oxytetracycline hydrochloride (OTCH) and minocycline hydrochloride (MCH). Binding rhodamine B (RhB) to gold nanoparticles (Au NPs) resulted in quenching of the fluorescence of RhB by a resonance energy transfer (FRET) mechanism, with Au NPs as the energy acceptors. The presence of TCs caused the release of RhB molecules and recovered their fluorescence, and this was used as a basis for the quantitative determination of TCs. The reaction was monitored spectrofluorimetrically by measuring the increase in fluorescence of RhB at 572 nm starting 5 min after mixing the reagents in Tris buffer solution (pH 6.5). The effect of various experimental factors such as buffer type, pH, concentrations of the involved reagents and reaction time were studied to optimize the reaction conditions. Under optimum conditions, the calibration graphs were linear within the ranges 2.08 × 10(-9) -1.04 × 10(-6) mol/L, 2.01 × 10(-9) -1.00 × 10(-6) mol/L and 2.02 × 10(-9) -1.01 × 10(-6) mol/L and detection limits (LODs) of 0.61 × 10(-9) , 0.32 × 10(-9) and 0.66 × 10(-9) mol/L were calculated for TCH, OTCH and MCH, respectively, with corresponding percent relative standard deviations (%RSDs) of 1.18, 1.21 and 1.54 (n = 5). The method was successfully applied to the determination of TCs in drinking water, human urine, bovine milk and breast milk samples.

Determination of ethanol using permanganate-CdS quantum dot chemiluminescence system.

A novel and highly sensitive chemiluminescence (CL) method for the determination of ethanol was developed based on the CdS quantum dots (QDs)-permanganate system. It was found that KMnO4 could directly oxidize CdS QDs in acidic media resulting in relatively high CL emission. A possible mechanism was proposed for this reaction based on UV/Vis absorption, fluorescence and the generated CL emission spectra. However, it was observed that ethanol had a remarkable inhibition effect on this system. This effect was exploited in the determination of ethanol within the concentration range 12-300 µg/L, with detection at 4.3 µg/L. In order to evaluate the capability of presented method, it was satisfactorily utilized in the determination of alcohol in real samples.

Potassium permanganate-acridine yellow chemiluminescence system for the determination of fluvoxamine, isoniazid and ceftriaxone.

Based on the oxidation of acridine yellow by permanganate in basic medium, a new chemiluminescence system was developed for the sensitive determination of some important drugs. The remarkable inhibiting effect of fluvoxamine, ceftriaxone and isoniazid on this reaction was applied to their detection. A possible mechanism was proposed for this system based on chemiluminescence emission wavelengths and experimental observations. Under optimum conditions, calibration graphs were obtained for 1 × 10(-9) to 1 × 10(-6) mol/L of fluvoxamine; 2 × 10(-8) to 8 × 10(-6) mol/L of ceftriaxone and 5 × 10(-8) to 4 × 10(-5) mol/L of isoniazid. This proposed method was satisfactorily used in the determination of these drugs in pharmaceutical samples and human urine and serum.