Recovery Values Research Articles

A Reliable and Straightforward Combination of vortex-assisted Dispersive Magnetic solid-phase Extraction with Direct Sorbent Sampling for Highly Sensitive Silver Determination in Water Samples Using Flame and Metal Furnace AAS.

In the present paper, the assessment of vortex-assisted dispersive magnetic solid-phase extraction using amino-functionalized mesoporous combined with direct magnetic sorbent sampling (DMSS) in flame or furnace atomic absorption spectrometry (FAAS or FF-AAS) was demonstrated for highly sensitive silver determination in water samples. The developed method showed significant enrichment factors compared to conventional pneumatic nebulization by FAAS, 607 for DMSS-FF-AAS and 114 for DMSS-FAAS. The analytical curve showed linearity in the range from 5.0 to 70.0µg L- 1 and 1.0 to 15.0µg L- 1 and limits of detection of 0.59 and 0.09µg L- 1 for DMSS-FAAS and DMSS-FF-AAS, respectively. The intra and inter-day precision evaluated as a percentage of the relative standard deviation (RSD,%) ranged from 1.89 to 4.71% for levels of 25.0 and 65.0µg L- 1. The method was applied in different kinds of water samples without matrix effects, yielding recovery values from 90 to 110%.

Lab-on-a-chip paper-based electrochemically assisted solid-phase microextraction and ion selective sensor for determination of naproxen in biological fluid samples

BackgroundThe integration of paper-based analytical devices with lab-on-a-chip technology has opened up new possibilities for miniaturized, rapid, low cost and portable diagnostic testing in resource limited settings. This work introduces an integrated lab-on-a-chip platform coupling paper-based analytical devices (LOC-PADs) for dual usage: electrochemically controlled solid-phase microextraction (EC-SPME) and determination of naproxen (NAP) by potentiometric ion-selective electrode (ISE) in biological samples. ResultsConductive papers were successfully fabricated by a chemical procedure. Thereupon, a conducting molecularly imprinted polymer (CMIP) film based on PPy and an anionic model drug (NAP) as a template were applied to the conductive paper substrate via electrochemical methods. A microfluidic chip device was employed to assess the analytical performance of the fabricated paper-based CMIP. The designed chip is divided into two parts with a microfluidic channel between them. The first chamber is an extraction zone for EC-SPME of NAP by using the CMIP paper as a selective sorbent. The second chamber is the detection zone and consists of a paper-based NAP ion selective sensor for potentiometric detection of drug. The analytical process was investigated and optimized for each chamber. Remarkable selectivity towards NAP was achieved in the concentration range from 4.0 × 10−7 to 1.0 × 10−2 mol L−1 with determination coefficient (R2 = 0.99) and the limit of detection (LOD) was 2.0 × 10−7 mol L−1. Anionic Nernstian compliance was gained −58.5 ± 0.5 mV decade−1, and response time in the detection step was 7s for ISE. Satisfactory spiking recovery values within the acceptable range of 90–110 % with RSDs ≤7 % were achieved for the analysis of real samples with fully portable LOC device. SignificanceThe LOC-PADs were favorably used for selective extraction and determination of NAP in serum and saliva samples, respectively. EC-SPME caused sample clean-up, reduced or eliminated different interferences and enhanced selective response of ISE as detection zone of device. Integration of EC-SPME and ISE in a single chip enabled easy and fast determination of trace amounts of NAP in limited real sample volumes, and fully portable advantages.

Fluorescence-based determination of tobramycin using a portable smartphone-based device

The study presents the development of a robust portable smartphone-based device for determining tobramycin in drugs and urine by a fluorescence-based method. As existing analytical methods for the determination of tobramycin often require complex equipment and time-consuming procedures, the proposed approach offers simplicity, portability and real-time monitoring capabilities. The spectrofluorimetric method is based on the reaction of tobramycin and fluorescamine in an alkaline medium. The measurement of analytical signals was enabled with a specially designed device integrating a 3D printed adapter, LEDs, a macro lens, an Arduino-based microcontroller, and asmartphone. The traditional spectrofluorimetry was used as a reference method. Preliminary and optimisation studies were conducted to select the most suitable experimental conditions (e.g. reagent concentration and reaction time) as well as instrumental parameters (e.g. selection of the appropriate RGB model component, ISO, and white balance). The performance of the method was validated, and then verified against conventional spectrofluorimetry, showing comparable accuracy and precision. The method implemented in a smartphone-based device showed a linear range of 0.10–1.00 mgL-1 with a detection limit of 0.03 mgL-1. Synthetic samples were tested to verify analytical usability, followed by analysis of pharmaceutical and urine samples. The method showed good precision (CV<3.4 %) and recovery values (92.3–114.1 %), consistent with spectrofluorimetric results (CV<5.9 %, recovery 92.3–119.8 %). Comparison with other methods highlighted the simplicity and efficiency of the developed approach. The research reveals that it is competitive with existing well-established methods. The proposed device offers reliable results with low reagent and sample consumption, making itsuitable for on-the-go analysis in non-laboratory conditions.

Evaluation of the presence of emerging contaminants in wastewater and seawater using automated solid-phase extraction and ultra-high-performance liquid chromatography coupled to tandem mass spectrometry

The presence of emerging contaminants in water constitutes one of the main ways of human exposure to them, which can cause severe effects on health. In this sense, their adequate elimination through appropriate treatments plays a fundamental role, being necessary to monitor the effluents from wastewater treatment plants, as well as the areas close to their discharge. The aim of the present work has been the development and validation of an analytical methodology to determine 15 organic contaminants of emerging concern in wastewater as well as in seawater samples using an automated solid-phase extraction system and an ultra-high-performance liquid chromatography coupled to tandem mass spectrometry instrument. Matrix-matched calibration showed good linearity with determination coefficients ≥ 0.990. Likewise, matrix effect assessment showed a significant signal suppression in almost all the analytes demonstrating the need to consider such effect for a proper quantification of the analytes. Recovery values ranged from 74.7 to 109% with relative standard deviation values ≤ 20.5% for most analytes. Regarding seawater and wastewater samples, 11 of the target analytes were detected in, at least, one sample at concentrations from below limit of quantification of the method to 217 ± 92 ng l-1 in seawater and up to 2340 ± 107 ng l-1 in wastewater samples.

Systematic investigation on bastnaesite flotation in the presence of dissolved calcium ions using organic acids as chelating agents

This study systematically investigated the potential of organic acids as Ca2+ ions chelating agents in bastnaesite flotation. Naturally, bastnaesite is associated with calcium-bearing gangue minerals, such as calcite (CaCO3) and fluorite (CaF2). The flotation beneficiation of bastnaesite in the presence of calcium-bearing minerals (e.g., calcite) is exceptionally complex due to the release of Ca2+ ions into the flotation pulp which changes the solution chemistry and bastnaesite surface properties. This study seeks to address the challenge of dissolved Ca2+ ions on bastnaesite flotation using organic acids, namely lactic, succinic, and citric acids. Systematic micro-flotation experiments were followed by electro-kinetic tests, solution chemistry studies, and XPS characterization. The results of this study showed that the elevated concentration of Ca2+ ions dramatically decreased bastnaesite flotation recovery values. However, organic acids formed soluble chelates with Ca2+ ions, effectively eliminating the detrimental impact of dissolved Ca2+ ions on bastnaesite flotation.

Spectrophotometric Determination of Cobalt(II) by Natural Deep Eutectic Solvent (NADES) Air-Assisted Dispersive Liquid-Liquid Microextraction (AA-DLLME)

Cobalt is beneficial for human activity but has adverse effects when discharged in large quantities. Therefore, its precise and accurate quantification in samples is of importance. Here, a natural deep eutectic solvent (NADES), composed of camphor (H-bond acceptor) and menthol (H-bond donor), has been used for the preconcentration of Co(II) from water samples before determination by a spectrophotometer at 398 nm. The 8-hydroxyquinoline-Co(II) complex was transferred to the NADES using air-assisted dispersive liquid-liquid microextraction (AA-DLLME). The extraction efficiency was enhanced through fine tuning of various parameters, including pH, NADES volume, and quantity of dispersant. Similarly, the centrifugation rate and time, quantity of the complexing agent, matrix effects, and salt concentration were also evaluated. Under the optimized conditions, an enrichment factor of 37.5 and a preconcentration factor of 37.5 were obtained. The limits of detection (LOD) and quantification (LOQ) were 0.44 µg/L and 1.47 µg/L, respectively. For seven replicates of 50 µg/L Co(II), the relative standard deviation was 3.2%. The developed method was employed for the determination of Co(II) in water samples, with quantitative recovery values from 94.5 to 98.5%.

Synthesis of Ultralow-Density Polyethylene Elastomers Using Triarylnaphthyl Iminopyridyl Ni(II) Catalysts.

Recently, the chain-walking ethylene polymerization strategy has garnered widespread attention as an efficient and straightforward method for preparing polyolefin elastomers. In this study, a series of 2,4,8-triarylnaphthyl iminopyridyl nickel catalysts were synthesized and used in ethylene polymerization. These catalysts demonstrated moderate catalytic activity (105 g mol-1 h-1), producing high-molecular-weight (up to 145.5 kg/mol) polyethylene materials with high branching degrees (75-95/1000C) and correspondingly low melting points. Detailed analysis using 13C NMR spectroscopy revealed that the polyethylenes primarily featured methyl and long-chain branches. Mechanical testing of the polyethylene samples obtained from catalysts Ni1-Ni3 exhibited moderate stress at break (4.64-6.97 MPa) coupled with a very high strain at break (1650-3752%), indicating their very good ductility. Furthermore, these polyethylenes showcased great elastic recovery abilities, with strain recovery values ranging from 72% to 85%. In contrast, the polyethylene produced by Ni4 displayed notably inferior tensile strength (0.16 MPa) and tensile recovery (43%). To the best of our knowledge, this study represents the inaugural utilization of a nickel iminopyridyl catalyst in the preparation of a polyethylene thermoplastic elastomer.

Electrochemical sensor for the analysis of 5-hydroxymethylcytosine in the presence of cytosine using pencil graphite electrode

In recent years, important efforts have been made to elucidate the mechanisms of epigenetic regulation, and one of the most studied epigenetic modifications was DNA methylation/demethylation. In this study, the voltammetric behaviour of 5-hydroxymethylcytosine was studied in the pH range of 2.00–11.00 using pencil graphite electrodes by differential pulse and square wave voltammetry. The effect of buffer solutions, scan rate, square wave voltammetry parameters, and stripping conditions on the voltammetric responses of 5-hydroxymethylcytosine were performed. The electrochemical oxidation process of 5-hydroxymethylcytosine on the pencil graphite electrode was realized under adsorption control. In human urine, by square wave stripping voltammetry, 5-hydroxymethylcytosine was quantified in a concentration range of 1.00 × 10−5 M-2.00 × 10−4 M. The proposed method was tested in the presence of cytosine in human urine. The recovery value of 5-hydroxymethylcytosine was found to be 99.57 %.

Fast screening of Milk for Deoxynivalenol

A 2D platform was designed and validated for fast screening of milk for deoxynivalenol. The qualitative and quantitative assay of deoxynivalenol in the milk samples was done using a 2D stochastic sensor based on single walled carbon nanotubes modified with [N-(pyridine-4-yl-methyl)]octadec-9-enamide. The working concentration range was between 10−15 and 10−6 g mL−1, with a sensitivity of 5.48 × 105 s−1g−1mL, and a limit of determination of 1 fg mL−1. Recovery values higher than 99.00 % with RSD values lower than 1.00 % were recorded for the determination of deoxynivalenol in cow's and in the vegetarian (coconut milk, soy milk, almond milk) milk.

Sensitive analysis of some detrimental volatile organic compounds in fabric, carpet and air freshener using solid phase extraction and gas chromatography–mass spectrometry

Benzene, toluene, ethylbenzene and xylene are known to be lethal environmental contaminants that have carcinogenic and mutagenic influences in human being while styrene and benzaldehyde have a neurotoxic effect. In other hand, the constituents of air freshener considered as a probable source of volatile organic compound. In the present work, a solid phase extraction and gas chromatography–mass spectrometry (GC-MS) technique has been optimized and applied to the fabric, carpet and air freshener samples to determine the trace amounts of benzene, toluene, ethylbenzene, xylene, styrene and benzaldehyde. The SupelcleanTM ENVITM - 18 cartridge with dichloromethane extracting solvent were found to be the optimal procedures. The system presented excellent performance in terms of limit of detection (0.08-0.61 ng/mL), coefficient of determination (0.994-0.997), precision with the relative standard deviation values ranging from 0.05-2.57%. According to the results, the concentration of benzene, toluene, ethylbenzene, xylene, styrene and benzaldehyde in fresheners’ samples was found in the range 0.03-53.27, 0.03-7.12, 0.02-6.51, 0.05-96.44, 0.04-7.06 and 0.22-23.02, respectively. The excellent recovery values were also obtained up to 99.93%. The SupelcleanTM ENVITM - 18 GC-MS system was found to appropriate for the monitoring of analytes in fabric, carpet, air freshener samples, and other samples of the similar constituents. KEY WORDS: BTEX, Styrene, Benzaldehyde, Air freshener, Solid phase extraction, Gas chromatography–mass spectrometry Bull. Chem. Soc. Ethiop. 2024, 38(6), 1543-1556. DOI: https://dx.doi.org/10.4314/bcse.v38i6.4

A novel green synthesis of silver nanoparticles from Anisosciadium seeds extract as sensitive fluorescent nanosensors for determination of esomeprazole and lansoprazole in dosage forms and human plasma

This study introduces a novel and eco-friendly method for the spectrofluorimetric determination of two important anti-GERD drugs, esomeprazole and lansoprazole. The study depends on synthesis of silver nanoparticles from Anisosciadium seeds extract as a reducing agent, for the first time. The synthesized silver nanoparticles were characterized by applying various microscopic and spectroscopic methods, including Fourier Transform Infrared, High Resolution Transmission Electron Microscopy, Energy-Dispersive X-Ray Analysis, Dynamic Light Scattering technique, Ultraviolet–Visible spectrophotometry, and spectrofluorimetry. The produced silver nanoparticles demonstrated an emission band at 311 nm if excited at 222 nm, and showed powerful blue fluorescence when exposed to UV light. The obtained silver nanoparticles were employed as fluorescent nanoprobes for the determination of esomeprazole and lansoprazole spectrofluorimetrically, depending on their quenching of the native fluorescence of silver nanoparticles quantitatively. This study is the first spectrofluorimetric strategy for the determination of the investigated medications with the use of silver nanoparticles without the requirement for any pre-derivatization stages or large volumes of organic solvents. As investigated medications don’t display native fluorescent characteristics; the importance of the presented method increases. The suggested study demonstrated excellent linearity over the ranges of 1.0–10.0 μg/mL and 0.1–1.0 μg/mL with detection limits of 0.17 μg/mL and 0.015 μg/mL for esomeprazole and lansoprazole, respectively. The presented study was employed for the determination of esomeprazole and lansoprazole in human plasma samples and dosage forms with low % relative standard deviation and high % recoveries values. Greenness profile of the suggested method was assessed utilizing two various metrics, including Green Analytical Procedure Index (GAPI) and Analytical GREENNESS metric approach (AGREE), verifying lower environmental impact of the method and excellent eco-friendliness. The proposed strategy was validated in accordance with International Council for Harmonization(ICH) Q2 (R2) guidelines.

A cost-effective method for the sensitive detection of levofloxacin using a 3D composite electrode composed of nail polish, graphite and aluminium oxide.

The potential impact on human health and the environment has spurred significant interest in detecting and quantifying pharmaceutical compounds across various matrices, from environmental to biological samples. Here, we present an electrochemical approach for determining levofloxacin in drug, synthetic urine, water, and breast milk samples. An affordable sensor was constructed using 3D printing and composite material based on nail polish, graphite, and aluminum oxide. The conductive composite material was characterized spectroscopically, electrochemically, and by imaging techniques. Subsequently, an electrochemical method based on square wave voltammetry was optimized and applied. The method exhibited good sensitivity (5.11 ± 0.0912 μA L μmol-1 cm-2) and enhanced stability (RSD = 7.2%), with electrochemical responses correlating with the concentration of levofloxacin in the samples tested, yielding recovery values in the range of 98 to 111%. The developed method demonstrated a robust linear working range from 2 to 100 μmol L-1 and a nanomolar detection limit of 128 nmol L-1, rendering it suitable for quantitative analysis. The sensor also shows promise as a platform for the sensitive detection of pharmaceutical compounds, contributing to greater safety and sustainability in these domains.

A novel nanovoltammetric sensor design for the sensitive determination of caffeic acid in Turkish coffee

Caffeic acid has anti-inflammatory, antibacterial, anticarcinogenic and immunomodulatory properties as well as antioxidant properties. Therefore, precise determination of the quantity of this acid is important for analytical and therapeutic interests as well as for the safety and quality of food samples. This study aims to determine the amount of caffeic acid in Turkish coffee by using the square wave voltammetry technique. This method has been successfully applied for the precise determination of caffeic acid with a platform in which the glassy carbon electrode is constructed with a modifier obtained based on the synergistic effect of functionalized multi-walled carbon nanotubes with boron oxide nanoparticles. The proposed platform and method gave a quantification limit of 0.04 nM in a dynamic range of 1.0 nM ˗ 40 μM for caffeic acid and was successfully used in the Turkish coffee sample to determine caffeic acid. In addition, the results are found in line with the results obtained by UV-Vis spectrophotometry method, and the good recovery values also imply the feasibility of the platform for practical application.

Sustainable Recovery of Polyphenols and Carotenoids from Horned Melon Peel via Cloud Point Extraction.

Using natural plant extracts as food additives is a promising approach for improving food products' quality, nutritional value, and safety, offering advantages for both consumers and the environment. Therefore, the main goal of this study was to develop a sustainable method for extracting polyphenols and carotenoids from horned melon peel using the cloud point extraction (CPE) technique, intending to utilize it as a natural food additive. CPE is novel promising extraction method for separation and pre-concentration of different compounds while being simple, inexpensive, and low-toxic. Three parameters within the CPE approach, i.e., pH, equilibrium temperature, and equilibrium time, were investigated as independent variables through the implementation of Box-Behnken design and statistical analyses. The optimized conditions for the maximum recovery of both polyphenols and carotenoids, reaching 236.14 mg GAE/100 g and 13.80 mg β carotene/100 g, respectively, were a pH value of 7.32, an equilibrium temperature of 55 °C, and an equilibrium time of 43.03 min. The obtained bioactives' recovery values under the optimized conditions corresponded to the predicted ones, indicating the suitability of the employed RSM model. These results highlight the effectiveness of CPE in extracting bioactive compounds with varying polarities from agricultural by-products, underscoring its potential for enhancing the value of food waste and advancing sustainable practices in food processing. According to microbiological food safety parameters, the optimal CPE extract is suitable for food applications, while its storage under refrigerated and dark conditions is particularly beneficial. The CPE extract's enhanced stability under these conditions makes it a more viable option for long-term storage, preserving both safety and quality.

Versatile and reliable extraction of phytosterols employing sonochemical synthesized molecularly imprinted polymer

Phytosterols (PSs) are bioactive compounds in the sterol family, present in numerous complex food and plant matrices in free and conjugated forms. The interest in these compounds arises for phytotherapeutic purposes, particularly for their action on cholesterol metabolism and impact on cardiovascular diseases. There is a need to develop approaches that can selectively extract target analytes and accurately identify and quantify them with high precision. This work proposed the synthesis of molecularly imprinted polymers (MIPs) for PSs with a sonochemical approach, enabling a rapid polymerization step (5 min). This proposed MIP was able to extract 8 PSs (brassicasterol, stigmastanol, campesterol, campestanol, stigmasterol, β-sitosterol, Δ5-avenasterol, α-spinasterol) from a wide range of plant and food matrices belonging to different classes (Brassicaceae, dried fruits and Leguminosae) and was coupled to ultra-high liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS). MIP based on dispersed solid phase extraction (dSPE-MIP) and targeted analysis has proven to be particularly effective in addressing the challenges associated with the complexity of plant-derived matrices, minimising interferences. This was demonstrated by the excellent control of the matrix effect, which was within ±15 %, ensuring the robustness and reliability of the method. The identification and quantification of 8 different PSs was successfully achieved with satisfactory recovery values ranging from 65 % to 100 %. The proposed strategy offers an affordable alternative to classical methods, providing enhanced sensitivity, selectivity and overall performance.

Chromogenic probes featuring hydroxyethyl acetate as metal ion binding site: Selective dual-mode response and quantitative analysis of Ag+ at micellar interface

This study presents the design and synthesis of Charge Transfer-based chromogenic probes utilizing hydroxyethyl acetate (HEA) as a metal ion chelating site, and anthraimidazoldione (1) and bisindolyl methane (2) as signalling moieties. Both compounds demonstrated pH-sensitive nanoaggregate formation in aqueous solutions, as confirmed by various spectroscopic studies, dynamic light scattering (DLS) analysis, and field emission scanning electron microscopy (FESEM) imaging. Despite containing the HEA unit, compound 1 displayed no interaction with metal ions either in water or acetonitrile medium. However, in Brij-58 micelles, compound 1 exhibited a selective color-changing response to Ag+ ions accompanied by fluorescence enhancement. Mechanistic investigations revealed that Ag+ ions bound to the HEA unit, altering the charge transfer state of the probe. Compound 2, with bisindolyl methane as signalling moiety, demonstrated a superior response to Ag+ ions, attributed to differences in the pKa values of coordinating tertiary nitrogen centers and aggregation behavior. The developed sensory system was applied for silver ion estimation in Silverex ionic gel and diluted human urine samples, demonstrating high recovery values (~100 %) with low standard deviation (<5 %). These results suggest suitability of the present method for quantitative analysis of real-life samples.

Development of Analytical Strategy for the Determination of Cadmium by Flame Atomic Absorption Spectrometry After Dithizone/Deep Eutectic Solvent Probe Based Liquid Phase Microextraction

Liquid phase microextraction (LPME) with a dithizone/deep eutectic solvent (DTZ-DES)-based probe was employed for the determination of trace cadmium by flame atomic absorption spectrometry (FAAS). All extraction parameters were univariately optimized to achieve the highest efficiency and the limits of detection and quantification were 3.5 and 11.8 ng mL−1. Good linearity was obtained from 10 to 200 ng mL−1 with a regression coefficient (R2) of 0.9979. The sensitivity of FAAS system was improved 26.9-fold by the microextraction procedure. The accuracy and applicability of the method were investigated with recovery experiments carried out using corn silk tea extracts. The recovery values with matrix matching calibration were from 81.3 to 114.3%, demonstrating that this environmentally friendly method is applicable for determination of cadmium in tea samples with good accuracy.

Mechanochemically synthesized flower-like bismuth oxyhalides: An electrochemical platform for diclofenac detection

The emerging drug diclofenac (DICF) has been found to penetrates aquatic systems at alarming concentrations and poses serious and irreversible ecotoxicological threats around the world. In this work, we present the solid-state mechanochemical synthesis of 3D flower-like bismuth oxyhalides (BiOX, where X = Cl, Br, and I) as electrode materials for electrochemical detection of DICF. The characteristics of the flower-like BiOX are systematically investigated using spectroscopic and microscopic techniques. The BiOI-modified glassy carbon electrode (GCE) exhibits superior electrochemical performance for DICF detection compared to the pristine GCE, BiOCl/GCE, and BiOBr/GCE. The 3D flower-like architecture of BiOI facilitates favorable electrocatalytic activities due to its abundant electroactive sites, good conductivity, large surface area, and fast ion diffusion. Notably, the BiOI/GCE displays wide linear ranges (0.5–11.3 & 11.3−76), a low limit of detection (0.11 μM), high sensitivity (1.33 μA μM–1 cm–2), excellent repeatability (2.91 %), good reproducibility (2.88 %), and anti-interfering ability (<±5 %). To validate the practicality of the fabricated BiOI/GCE, the quantitative detection of DICF in human urine and river water is demonstrated and achieves acceptable recovery values. This study introduces an innovative approach to design and produce electrode materials with distinct properties, enabling enhanced electrocatalysis for various electrochemical sensing applications.

Determination of Some Element’s Migrants in Aqueous Simulant from Plastic Food Contact Products by Inductively Coupled Plasma Mass Spectrometer

Various chemicals present at different stages in the food supply chain can lead to the leaching of heavy metals. These metals can accumulate in the human body through the consumption of contaminated food. Consequently, it is necessary to validate an analytical technique for the quantification chemical that could contaminate food. This study presents a rapid, straightforward, and efficient analytical method for the direct quantification of some potentially toxic elements in aqueous simulants from plastic food contact products using an inductively coupled mass spectrometer (ICP-MS). The method’s validation encompassed the study of the estimated detection limits, practical quantification limits, linearity, accuracy, and measurement uncertainty of aluminium (Al), antimony (Sb), arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni), and zinc (Zn) under optimized ICP-MS conditions. The estimated detection limits ranged from 7.5 × 10−4 to 0.074 mg/kg, while practical quantification limits spanned from 0.02 to 0.8 mg/kg. The average recoveries ± standard deviations at different spiking levels were varied between 85.7 ± 1.51 and 115.6 ± 0.88% with coefficients of variation between 0.42 and 5.85%. The method trueness was verified by using references materials (test material in aqueous acetic acid) purchased from Food Chemistry Proficiency Testing and Analysis (FAPAS) yielding satisfactory results within acceptable recovery and Z-score values. The method precision, in terms of relative standard deviation (RSD), was being below 4.22%. The method uncertainty expressed as expanded uncertainty of all validated elements was found to be ≤ 21.9%. Validated method was employed to determine specific elements in aqueous simulants of thirty commercial plastic food packaging samples, representing three distinct types of plastic polymers. The results showed that the mean concentrations, in mg/kg, were as follows: 2.04 (Al), 0.02 (As), 0.02 (Cd), 0.02 (Co), 0.06 (Cr), 0.41 (Cu), 1.55 (Fe), 0.09 (Mn), 0.15 (Ni), 0.07 (Pb), 0.05 (Sb), and 0.81 (Zn). Furthermore, 30% of analyzed samples exceeding the maximum permissible limits of Al for plastic materials and articles intended to come into contact with food.

A Smartphone Operated Intelligent Stochastic Miniplatform for On-Site Screening of Milk for Fast Determination of Ochratoxin A

Ochratoxine A is a very stable mycotoxin which cannot be destroyed below 250°C. Found in grains, coffee, grapes, wine, milk, and meat, it can produce kidney damage and cancer. Therefore, a smartphone operated intellingent stochastic miniplatform was designed, characterised, and validated for the on-site screening of milk for fast determination of ochratoxine A. (Z)-N-[2-(4-hydroxyphenyl) ethyl]octadec-9-enamide was used as modifier of a gold matrix for a screen printed stochastic sensor used as sensing tool in the design of the miniplatform. A wide linear concentration range (1.0 × 10−15 − 1.0 × 10−7 mol l‒1) and a low limit of quantification of 1 fmol l‒1 were achieved for the assay of ochratoxin A. Recovery values higher than 99.00% were obtained for ochratoxine A, when the miniplatform was used for the screening of cow’s milk and vegetarian milk.