Microextraction with smartphone detection of thiocyanate in saliva of tobacco smokers using paper-based analytical method

This study presents a novel, cost-effective approach involving spectrophotometric and smartphone paper-based (SPB) methods and a distinctive salting-out air-assisted dispersive microextraction procedure to quantify thiocyanate in saliva samples. The method relies on the inhibitory effect of thiocyanate on quinoneimine dye formation during the Emerson reaction with sodium hypochlorite. Spectrophotometry quantifies the extracted dye by monitoring quinoneimine color intensity reduction at 525 nm. In the SPB method, extracted dye is applied to a paper strip, a smartphone captures the colored paper, and an application analyzes red, green, and blue components. All analyte determination and extraction variables were explored. Both methods exhibit good linearity (10-100 μg/L) with a coefficient of determination of 0.9991 and a limit of detection of 7.5 μg/L for the spectrophotometric method, and a coefficient of determination of 0.9988 and a limit of detection of 8.8 μg/L for the SPB method. The calculated values for the enrichment factor and extraction recovery of the developed extraction methodology were 46% and 93%, respectively. The methods detect thiocyanate in saliva samples, producing results comparable to a validated method.

Hyperbranched aromatic polyamide modified magnetic nanoparticles for the extraction of benzoylurea insecticides

Herein, a novel hyperbranched aromatic polyamide-coated magnetic sorbent was prepared by in situ polymerization on the surface of amino-functionalized Fe₃ O₄ nanoparticles. The magnetic sorbent was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, elemental analysis, Brunauer-Emmett-Teller measurement, and X-ray photoelectron spectroscopy, etc. The new magnetic sorbent was used in the magnetic solid-phase extraction for the detection of seven benzoylurea insecticides. Under optimum conditions, low method detection limits (0.56-1.20 ng/mL), acceptable coefficient of determination (0.9967-0.9996), wide linear ranges (2.5-500.0 ng/mL), and good repeatability (intraday: 2.0-7.3%; interday: 1.9-9.2%) were achieved. The magnetic solid-phase extraction method based on the new magnetic sorbent showed good reliability in the analysis of seven benzoylurea insecticides in real water samples, as the relative recoveries were in the range from 80.1 to 116.3% with satisfactory RSDs (0.1-9.8%). By means of density functional theory and semiempirical quantum mechanical, the binding configuration and interaction energy of hyperbranched aromatic polyamide and benzoylurea insecticides were calculated. The result of theoretical calculation revealed that the adsorption of benzoylurea insecticides by hyperbranched aromatic polyamide was derived from hydrogen bonding and π-π stacking. The contribution of π-π stacking was greater than that of hydrogen bond, which was confirmed by energy decomposition analysis.

Polypyrrole coated ZnO nanorods on platinum wire for solid-phase microextraction of amitraz and teflubenzuron pesticides prior to quantitation by GC-MS

The authors describe a new sorbent for amitraz and teflubenzuron pesticides. It consists of a platinum wire coated with polypyrrole-coated ZnO nanorods. The nanocomposite was prepared by a two-step process. In the first step, oriented ZnO nanorods were hydrothermally grown in situ on a platinum wire. Subsequently, oxidative vapor phase polymerization of pyrrole was performed on FeCl₃-impregnated ZnO nanorods to give a porous polypyrrole film. The organic/inorganic nanocomposite synthesized through hydrothermal deposition and chemical vapor deposition polymerization yields material with attractive properties. The coated wire was applied to solid-phase microextraction of amitraz (in the form of 2,4-dimethylaniline resulting from the hydrolysis of amitraz) and teflubenzuron. The effects of extraction temperature, extraction time, sample pH value and salt concentration were optimized. The analytes 2,4-dimethylaniline and teflubenzuron were then quantified by GC-MS. Under optimum conditions, the LODs range between 0.1 and 0.15 ng.mL^-1. Relative standard deviations at two concentration are <8.3% for intraday precision and <10.3% for inter-day precision. In all cases, the fiber to fiber reproducibility is <12.2%. For both analytes the linear dynamic ranges are 0.5-300 ng.mL^-1. The procedure was successfully applied to the analysis of spiked agricultural water samples. Graphical abstract A novel inorganic/organic hybrid nanocomposite was synthesized through in situ hydrothermal deposition of ZnO nanorods and ten placing a thin layer of polypyrrole on them by chemical vapor deposition polymerization. This nanocomposite was applied to fabricate a solid-phase microextraction fiber for the extraction of amitraz and teflubenzuron pesticides residue from agricultural samples prior to their quantitation by GC-MS.

Dispersive micro-solid-phase extraction of benzoylurea insecticides in water samples with hyperbranched polyester composite as sorbent

Hyperbranched polyester was used as efficient and accessible sorbent in the dispersive micro-solid-phase extraction method.

Ionic liquid-modified luffa sponge fibers for dispersive solid-phase extraction of benzoylurea insecticides from water and tea beverage samples

Ionic liquid-modified luffa sponge fibers were used as efficient and environmentally friendly sorbents in the dispersive solid-phase extraction method.

Analytical sonochemistry; developments, applications, and hyphenations of ultrasound in sample preparation and analytical techniques

Ultrasonic assistance is one of the great successes of modern analytical chemistry, which uses this energy for a variety of purposes in relation to sample preparation and development of methods for the analysis of numerous contaminants including organic and inorganic compounds. This review will attempt to provide an overview of more recent applications of ultrasound in different environmental and biological samples such as food, soil and water as well as a brief description of the theoretical understanding of this method. Also, the possibility of coupling ultrasound with other analytical techniques will be discussed.