A robotic magnetic nanoparticle solid phase extraction system coupled to flow-batch analyzer and GFAAS for determination of trace cadmium in edible oils without external pretreatment

Nanoscale Materials Applying for the Detection of Mycotoxins in Foods

Trace amounts of mycotoxins in food matrices have caused a very serious problem of food safety and have attracted widespread attention. Developing accurate, sensitive, rapid mycotoxin detection and control strategies adapted to the complex matrices of food is crucial for in safeguarding public health. With the continuous development of nanotechnology and materials science, various nanoscale materials have been developed for the purification of complex food matrices or for providing response signals to achieve the accurate and rapid detection of various mycotoxins in food products. This article reviews and summarizes recent research (from 2018 to 2023) on new strategies and methods for the accurate or rapid detection of mold toxins in food samples using nanoscale materials. It places particular emphasis on outlining the characteristics of various nanoscale or nanostructural materials and their roles in the process of detecting mycotoxins. The aim of this paper is to promote the in-depth research and application of various nanoscale or structured materials and to provide guidance and reference for the development of strategies for the detection and control of mycotoxin contamination in complex matrices of food.

Potentially Toxic Elements (PTEs) in Refined and Cold-Pressed Vegetable Oils Distributed in Ahvaz, Iran: a Probabilistic Health Risk Assessment

The concentration of potentially toxic elements (PTEs) in vegetable oils using inductively coupled plasma-optical emission spectrometry (ICP-OES) was measured. Probabilistic non-carcinogenic risk in consumers was estimated using the target hazard quotient (THQ) and total target hazard quotient (TTHQ) by Monte Carlo simulation (MCS) method. The highest content of PTEs was found in blend oil for As (0.39 ± 0.07 mg/L), in cold-pressed rapeseed oil for Cd and Cu (0.07 ± 0 and 0.40 ± 0.06 mg/L) respectively, in cold-pressed sunflower oil for Fe (0.15 ± 0.10 mg/L), in refined sesame oil for Ni and Pb (0.44 ± 0.07 and 0.65 ± 0.07 mg/L, respectively), and in cold-pressed sunflower and rapeseed oils for Zn (0.19 ± 0.04 mg/L). THQ in adults and children due to individual vegetable oils (cold-pressed and refined vegetable oil) was lower than 1 value. TTHQ in adults and children due to consumption of cold-pressed vegetable oils was 0.05 and 0.26, and also refined vegetable oil was 0.51 and 0.33, respectively. TTHQ due to consumption of both types of oils was less than 1; therefore, the population is not at risk of non-carcinogenicity.

The selective recognition mechanism of a novel highly hydrophobic ion-imprinted polymer towards Cd(ii) and its application in edible vegetable oil

Edible vegetable oils are easily contaminated by heavy metals, resulting in the oxidative degradation of oils and various health effects on humans. Therefore, it is very important to develop a rapid and efficient method to extract trace heavy metals from vegetable oils. In this work, a highly hydrophobic ion-imprinted polymer (IIP) was synthesized on a novel raspberry (RS)-like particle surface. The synthesized IIP@RS was characterized and used in solid-phase extraction (SPE) for the selective and fast adsorption of Cd(ii) from vegetable oils. The results showed that IIP was successfully coated onto RS particles with a high specific surface area (458.7 m² g⁻¹) and uniform porous structure. The contact angle (θ) value (141.8°) of IIP@RS was close to the critical value of super-hydrophobic materials, which is beneficial to their adsorption in hydrophobic vegetable oils. The IIP@RS also exhibited excellent adsorption ability and selectivity to Cd(ii) with a maximum adsorption capacity of 36.62 mg g⁻¹, imprinting factor of 4.31 and equilibrium adsorption rate of 30 min. According to isothermal titration calorimetry results, the recognition behavior of IIP@RS for Cd(ii) was mainly contributed by Cd(ii)-induced cavities during gel formation and coordination between Cd(ii) and –SH groups in imprinted cavities. Furthermore, the adsorption process driven by entropy and enthalpy was spontaneous at all temperatures. In real vegetable oil samples, IIP@RS-SPE adsorbed approximately 96.5–115.8% of Cd(ii) with a detection limit of 0.62 μg L⁻¹. Therefore, IIP@RS has wide application prospects in enriching and detecting Cd(ii) from vegetable oil.

Edible vegetable oils are easily contaminated by heavy metals, resulting in the oxidative degradation of oils and various health effects on humans.

Surface modified iron magnetic nanoparticles assisted Fenton digestion and extraction method for cadmium determination

This study presents a Fenton digestion method for milk samples based on UV irradiation for cadmium determination using flame atomic absorption spectrometry. The method was developed as an alternative to microwave digesters, using very basic apparatus and easy to acquire chemicals. Fenton digestion process was performed by the help of citric acid coated magnetic nanoparticles. Optimum conditions of the digestion process were applied to milk samples to evaluate analytical performance of the method. Limit of detection and limit of quantification values calculated for cadmium in milk were 0.53 and 1.8 mg/L, respectively. The method was applied to three different milk samples to validate the method's suitability and accuracy. Percent recovery values calculated for the samples spiked at two different concentrations ranged between 86 and 111%. Due to differences in the content of the spiked and control/standard milk samples, exact matrix matching calibration strategy using the same brand of milk sample in the preparation of calibration standard was employed and the accuracy of cadmium quantification was greatly enhanced (≈100%).

A fast, low-cost, sensitive, selective, and non-laborious method based on functionalized magnetic nanoparticles, magnetic solid-phase extraction, and fluorescent carbon dots for the fluorimetric determination of copper in wines without prior sample treatment

A new fluorimetric method for copper(II) determination in wines was developed combining functionalized magnetic nanoparticles (FMNP) and fluorescent carbon dots (FCD). To produce FMNP, Fe₃O₄ was coated with Al₂O₃ forming Fe₃O₄@Al₂O₃ core-shell magnetic nanoparticles and functionalized with PAN and SDS. FCD was synthesized from pineapple juice through hydrothermal carbonization. For copper determination, aliquots of wine, the FMNP dispersion, and Britton-Robinson buffer (pH = 4.0) were mixed under stirring to allow the adsorption of copper by FMNP. Cu-FMNP complex was attracted by a niobium magnet and, after discarding the non-magnetic material, the copper(II) ions were eluted with an FCD dispersion before fluorescence quenching measurements. The proposed method presented a linear range from 0.020 to 0.100 mg L^-1 (r² = 0.9953), RSD (intraday) < 3.0%, and recovery rates from 96 to 105 %. FMNP and FCD properties permitted extraction/preconcentration/determination of copper within 1 min with an enrichment factor of nine and without prior sample treatment.

A 3D-printed robotic system for fully automated multiparameter analysis of drinkable water samples

This work describes a 3D-printed robotic system named RSAWA (robotic system for automatic water analysis) for fully automated water analysis. RSAWA consists of a robotic arm coupled to a syringe pump, temperature and conductivity sensors, a low-cost webcam as colorimetric detector, and a 96-well microplate placed on a 3D-printed platform. The robotic system is controlled by software and it performs all analytical procedures. RSAWA was applied to measure conductivity (CDT), pH, total alkalinity (TA), total hardness (TH), chloride (Cl^-), nitrite (NO₂^-), total dissolved phosphorus (TP), and total iron (TI) in drinkable water samples. A simple circuit was designed for conductivity determinations, while colorimetric pH determinations were carried out using Hue values extracted from digital images and a pH universal indicator. HSV histograms were used to calculate Pearson's correlation coefficients, allowing the construction of accurate titration curves. In addition to achieving sample throughputs of 112 h^-1 for TA and TH determinations and 92 h^-1 for Cl^- determinations, RSAWA produced 99.5% less waste than the corresponding reference methods during titrations. Colorimetric measurements were performed through RGB vector norms calculated from digital images were used as analytical signals. Limits of quantification (μg L^-1) were 6.83, 13.0 and 1.5 mg L^-1 for NO₂^-, TP, and TI determinations, respectively. Sample throughputs (samples h^-1) were 83 for NO₂^- and TP and 72 for TI with a 98.5% reduction in waste generation. Thus, RSAWA is a low-cost, feasible, and environmentally friendly alternative to quickly and accurately determine several chemical and physicochemical parameters in aqueous samples.

Combination of supramolecular solvent-based microextraction and ultrasound-assisted extraction for cadmium determination in flaxseed flour by thermospray flame furnace atomic absorption spectrometry

This study describes the development of a new analytical method for cadmium determination in flaxseed flour based on ultrasound-assisted extraction combined with supramolecular preconcentration followed by thermospray flame furnace atomic absorption spectrometry. Cadmium from flaxseed flour was extracted by ultrasound-assisted radiation in acid medium (1.5 mol L-1HNO3) followed by liquid-liquid microextraction of the acid extractwith dodecanoic acid/THF supramolecular solvent using diethyl dithiophosphate as a chelating agent. The limit of detection and the analytical curve range were found to be 0.10 μg L-1 and 0.35 to 20.0 μg L-1, respectively. The cadmium concentration in the flaxseed flours was ranged from 0.11 ± 0.04 to 0.79 ± 0.03 µg g-1. The proposed methodis considered simpler, faster, low-cost, and environmentally friendly compared to procedures currently used for the determination of cadmium based on acid digestion and using graphite furnace atomic absorption spectrometry and inductively coupled plasma mass spectrometry.

Advanced Methodologies for Trace Elements in Edible Oil Samples: A Review

Advanced methodologies were applied for the detection of some elements at trace levels in edible oils. Trace elements play a role in oil stability, quality of edible oils and fats. In the present study, problems were addressed related to simple, cheap, less time consuming and suitable pretreatment advanced methods for suitable sample introduction and calibrations as well as the strategies and techniques are discussed. The present review is aimed to discuss the significance of simplifying sample treatments are offered for trace elements in oils. The period covered by this review is last twenty years. However, the various applications of advanced methodologies including extraction and microextraction. The scope of spectrometric techniques used for the analysis of trace elements in edible oils was discussed by new instrumental development trends.

Miniaturized analytical methods for determination of environmental contaminants of emerging concern - A review

The determination of contaminants of emerging concern (CECs) in environmental samples has become a challenging and critical issue. The present work focuses on miniaturized analytical strategies reported in the literature for the determination of CECs. The first part of the review provides brief overview of CECs whose monitoring in environmental samples is of particular significance, namely personal care products, pharmaceuticals, endocrine disruptors, UV-filters, newly registered pesticides, illicit drugs, disinfection by-products, surfactants, high technology rare earth elements, and engineered nanomaterials. Besides, an overview of downsized sample preparation approaches reported in the literature for the determination of CECs in environmental samples is provided. Particularly, analytical methodologies involving microextraction approaches used for the enrichment of CECs are discussed. Both solid phase- and liquid phase-based microextraction techniques are highlighted devoting special attention to recently reported approaches. Special emphasis is placed on newly developed materials used for extraction purposes in microextraction techniques. In addition, recent contributions involving miniaturized analytical flow techniques for the determination of CECs are discussed. Besides, the strengths, weaknesses, opportunities and threats of point of need and portable devices have been identified and critically compared with chromatographic methods coupled to mass chromatography. Finally, challenging aspects regarding miniaturized analytical methods for determination of CECs are critically discussed.

Automatic multicommuted flow-batch setup for photometric determination of mercury in drinking water at ppb level

Herein, a multicommuted flow-batch setup and a photometric procedure for the determination of mercury at the ppb level in aqueous samples are described. The setup was designed to implement a versatile solvent extraction and pre-concentration strategy by combining flow-batch and multicommuted flow analysis approaches. The photometric method was based on Hg(II) reaction with dithizone in a chloroform medium, which was also used as the extracting organic solvent. The flow analysis system was composed of a homemade syringe pump module, a set of solenoid valves, two Aquarius mini-pumps, and a flow-batch chamber. The homemade photometer was comprised of a light emitting diode (LED), photodiode, and homemade flow cell (50 mm length). The flow system and photometer were controlled using an Arduino Due board, running custom-written software. After optimizing the operational conditions, the effectiveness of the developed system was evaluated for the determination of the mercury concentration in drinking water. For accuracy assessment, samples were analyzed using a spiking methodology and an independent method, yielding a recovery ranging from 92% to 108%. Other important characteristics of the proposed method were found as follows: linear response range, 0.5-10.0 μg L^-1 (r = 0.9984); limit of detection 0.38 μg L^-1 Hg(II); consumption of dithizone and chloroform, 1.85 μg L^-1 and 0.8 mL per analysis, respectively; coefficient of variation, 2% (n = 10); sampling throughput, 20 determinations per h.

Analytical Methodology for Trace Determination of Propoxur and Fenitrothion Pesticide Residues by Decanoic Acid Modified Magnetic Nanoparticles

A sensitive, rapid, reliable, and easily applicable method based on magnetic solid phase extraction (MSPE) combined with HPLC-PDA was developed for monitoring propoxur (PRO) and fenitrothion (FEN) pesticides in environmental water samples. The effect of major experimental variables on the extraction efficiency of both the pesticides was investigated and optimized systematically. For this purpose, a new magnetic material containing decanoic acid on the surface of particles was synthesized and characterized by XRD, FT-IR, SEM, EDX, and TGA analysis in detail. The simultaneous determination of pesticide molecules was carried out by using a Luna Omega C18 column, isocratic elution of acetonitrile (ACN): Water (70:30 v/v) with a flow rate of 1.2 mL min^-1. After MSPE, the linear range for pesticide molecules (r² > 0.9982) was obtained in the range of 5-800 and 10-800 ng mL^-1, respectively. The limit of detections (LOD) are 1.43 and 4.71 ng mL^-1 for PRO and FEN, respectively while RSDs % are below 3.5%. The applicability of the proposed method in four different environmental samples were also investigated using a standard addition-recovery procedure. Average recoveries at two spiking levels were over the range of 91.3-102.5% with RSD < 5.0% (n = 3). The obtained results show that decanoic acid grafted magnetic particles in MSPE combined with HPLC-PDA is a fast and simple method for the determination of PRO and FEN in environmental water samples.

Magnetic nanoparticles in nanomedicine: a review of recent advances

Nanomaterials, in addition to their small size, possess unique physicochemical properties that differ from bulk materials, making them ideal for a host of novel applications. Magnetic nanoparticles (MNPs) are one important class of nanomaterials that have been widely studied for their potential applications in nanomedicine. Due to the fact that MNPs can be detected and manipulated by remote magnetic fields, it opens a wide opportunity for them to be used in vivo. Nowadays, MNPs have been used for diverse applications including magnetic biosensing (diagnostics), magnetic imaging, magnetic separation, drug and gene delivery, and hyperthermia therapy, etc. Specifically, we reviewed some emerging techniques in magnetic diagnostics such as magnetoresistive (MR) and micro-Hall (μHall) biosensors, as well as the magnetic particle spectroscopy, magnetic relaxation switching and surface enhanced Raman spectroscopy (SERS)-based bioassays. Recent advances in applying MNPs as contrast agents in magnetic resonance imaging and as tracer materials in magnetic particle imaging are reviewed. In addition, the development of high magnetic moment MNPs with proper surface functionalization has progressed exponentially over the past decade. To this end, different MNP synthesis approaches and surface coating strategies are reviewed and the biocompatibility and toxicity of surface functionalized MNP nanocomposites are also discussed. Herein, we are aiming to provide a comprehensive assessment of the state-of-the-art biological and biomedical applications of MNPs. This review is not only to provide in-depth insights into the different synthesis, biofunctionalization, biosensing, imaging, and therapy methods but also to give an overview of limitations and possibilities of each technology.