Solid-phase Extraction System Research Articles

Restricted-Access Media Column Switching Online Solid-Phase Extraction UHPLC-MS/MS for the Determination of Seven Type B Trichothecenes in Whole-Grain Preprocessed Foods and Human Exposure Risk Assessment.

With increasing health awareness and the accelerating pace of life, whole-grain prepared foods have gained popularity due to their health benefits and convenience. However, the potential risk of type B trichothecene toxins has also increased, and these mycotoxins in such foods are rarely regulated. In this study, a quantitative method combining a single-valve dual-column automatic online solid-phase extraction system with ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed for the first time using restricted-access media columns. This method can simultaneously determine trace residues of seven type B trichothecenes within 15 min. The method is convenient, sensitive (limit of detection and quantification of 0.05-0.6 μg/kg and 0.15-2 μg/kg, respectively), accurate (recovery rates of 90.3%-106.6%, relative standard deviation < 4.3%), and robust (>1000 times). The established method was applied to 160 prepared food samples of eight categories sold in China. At least one toxin was detected in 70% of the samples. Whole-wheat dumpling wrappers had the highest contamination rate (95%) and the highest total content of type B trichothecenes in a single sample (2077.3 μg/kg). Exposure risk assessment indicated that the contamination of whole-grain prepared foods has been underestimated. The total health risk index of whole-wheat dumpling wrappers, which are susceptible to deoxynivalenol, reached 136.41%, posing a significant threat to human health. Effective measures urgently need to be taken to control this risk.

New fabric phase sorptive extraction for nondestructive analysis of heritage textile samples

Several types of pesticides used in museum collections over time become dangerous for people who may handle textile articles treated with such substances. In the case of the analysis of ancient, modern, and contemporary textile materials, it is particularly important to keep the artifacts intact, as they cannot be replaced. The need to use micro- or nondestructive techniques led to the development of methods such as solid-phase microextraction (SPME), liquid‒liquid dispersive microextraction (DLLME), and single-droplet microextraction (SDME). In this paper is described an optimized extraction method of three pesticides (malathion, methoxychlor, and permethrin) by creating a non-destructive solid phase extraction system on a textile support, abbreviated FPSE – 100 % cotton fabric coated with a sol-gel solution prepared from a polymer (PEG or PDMS). To obtain a suitable FPSE, the following parameters were evaluated: polymer selection (individual or mixture of polymers), acid catalyst (trifluoroacetic acid, acetic acid and hydrochloride acid), amount of polymer (1.0 g, 2.5 g or 5.0 g), polymerization time (30 min, 120 min and 240 min), ultrasonic bath temperature (40 °C and 70 °C), and type of bath to obtain the sol-gel (ultrasonic bath, water bath with stirring and mechanical stirrer). To complete the FPSE optimization, the influence of pesticide extraction time on FPSE and desorption from FPSE in ethyl acetate was also assessed.The pesticides extraction yields obtained for the laboratory textile samples are in the range of 52.7 %–128.0 %. The technique proposed in the manuscript proved to be effective as a nondestructive tool for evaluating and quantifying the presence of pesticides in textile museum collections. The approach described here reduces heritage object damage due to sampling compared to methods commonly employed and may represent a starting point for future research.

Preparation and optimization of dummy molecularly imprinted polymer-based solid-phase extraction system for selective enrichment of p-toluene sulfonate esters genotoxic impurities

Sulfonate esters, one class of genotoxic impurities (GTIs), have gained significant attention in recent years due to their potential to cause genetic mutations and cancer. In the current study, we employed the dummy template molecular imprinting technology with a dummy template molecule replacing the target molecule to establish a pretreatment method for samples containing p-toluene sulfonate esters. Through computer simulation and ultraviolet–visible spectroscopy analysis, the optimal functional monomer acrylamide and polymerization solvent chloroform were selected. Subsequently, a dummy template molecularly imprinted polymer (DMIP) was prepared by the precipitation polymerization method, and the polymer was characterized in morphology, particle size, and composition. The results of the adsorption and enrichment study demonstrated that the DMIP has high adsorption capability (Q = 7.88 mg/g) and favorable imprinting effects (IF = 1.37); Further, it could simultaneously adsorb three p-toluene sulfonate esters. The optimal adsorption conditions were obtained by conditional optimization of solid-phase extraction (SPE). A pH 7 solution was selected as the loading condition, the methanol/1% phosphoric acid solution (20:80, v/v) was selected as the washing solution, and acetonitrile containing 10% acetic acid in 6 mL was selected as the elution solvent. Finally, we determined methyl p-toluene sulfonate alkyl esters, ethyl p-toluene sulfonate alkyl esters, and isopropyl p-toluene sulfonate alkyl esters in tosufloxacin toluene sulfonate and capecitabine at the 10ppm level (relative to 1 mg/mL active pharmaceutical ingredient (API) samples) by using DMIP-based SPE coupled with HPLC. This approach facilitated the selective enrichment of p-toluene sulfonate esters GTIs from complex API samples.

Development of a High-Throughput Analytical Method for Antimicrobials in Wastewater Using an Automated Pipetting and Solid-Phase Extraction System.

Antimicrobial resistance (AMR) has emerged and spread globally. Recent studies have also reported the presence of antimicrobials in a wide variety of aquatic environments. Conducting a nationwide monitoring survey of AMR in the environment to elucidate its status and to assess its impact on ecosystems and human health is of social importance. In this study, we developed a novel high-throughput analysis (HTA) system based on a 96-well plate solid-phase extraction (SPE), using automated pipetting and an SPE pre-treatment system. The effectiveness of the system as an HTA for antimicrobials in environmental water was verified by comparing it with a conventional manual analytical system in a domestic hospital over a period of two years and four months. The results of the manual analysis and HTA using a combination of automated pipetting and SPE systems were generally consistent, and no statistically significant difference was observed (p > 0.05) between the two systems. The agreement ratios between the measured concentrations based on the conventional and HTA methods were positively correlated with a correlation coefficient of r = 0.99. These results indicate that HTA, which combines automated pipetting and an SPE pre-treatment system for rapid, high-volume analysis, can be used as an effective approach for understanding the environmental contamination of antimicrobials at multiple sites. To the best of our knowledge, this is the first report to present the accuracy and agreement between concentrations based on a manual analysis and those measured using HTA in hospital wastewater. These findings contribute to a comprehensive understanding of antimicrobials in aquatic environments and assess the ecological and human health risks associated with antimicrobials and antimicrobial-resistant bacteria to maintain the safety of aquatic environments.

Capillary electrophoresis tandem mass spectrometry to determine multiclass cyanotoxins in reservoir water and spinach samples

Cyanotoxins constitute a group of toxic secondary metabolites, the presence of which in any water body poses a major health risk. Moreover, advanced organisms such as edible plants exposed to these toxins, are a possible pathway for human exposure. Green analytical chemistry is demanding environmentally friendly analytical techniques. In this sense, we propose the use of capillary electrophoresis coupled to tandem mass spectrometry (CE-MS/MS) to determine a mixture of eight cyanotoxins belonging to three different classes: cyclic peptides (microcystin-LR, microcystin-RR and nodularin), alkaloids (cylindrospermopsin and anatoxin-a) and three isomeric non-protein amino acids (β-methylamino-l-alanine, 2,4-diaminobutyric acid and N-(2-aminoethyl)glycine). Separation was achieved by using an acidic background electrolyte consisting of 2 M formic acid and 20% acetonitrile in water. Parameters affecting MS/MS detection and the sheath-liquid interface were also studied. Finally, a combination of pH-junction, field-amplified sample stacking (FASS) and acid barrage as online preconcentration strategies, was employed to improve sensitivity and efficiency. The online preconcentration applied, in combination with a dual cartridge solid-phase extraction (SPE) system, allows to obtain limits of detection in the very low range of µg·L−1 for these multiclass cyanotoxins in reservoir water samples (from 0.005 to 0.10 µg·L−1). Furthermore, for the first time cyanotoxins are analysed in spinach samples through CE-MS/MS using the same SPE procedure, following lyophilisation and solid-liquid extraction with 6 mL 80 % aqueous MeOH.

Caffeine quantification in dietary supplements using high-throughput on-line solid phase extraction coupled to Venturi easy ambient sonic-spray ionization mass spectrometry.

Caffeine is present in a large number of beverages and is an additive used in dietary supplements. Therefore, the concern about its quality and safety for consumers has been increasing and hence requires faster and simpler analytical methods to determine the caffeine amount. The high-throughput analysis is an appropriate solution to pharmaceuticals, bioanalysis, forensic and food laboratory routines. In this sense, Venturi easy ambient sonic-spray ionization mass spectrometry (V-EASI-MS), a specific ambient ionization source, is suitable to enable direct analysis of sample solutions in real time and is appropriate to be coupled to liquid chromatography (LC). The development of an on-line solid phase extraction system coupled to V-EASI-MS optimizes the advantages of LC-MS hyphenation by enhancing the figures of merit of the analytical method according to AOAC guidelines and simultaneously minimizing the runtime analysis to 1.5 min per sample, as well as sample preparation steps and solvent consumption, which is currently a challenge for quantitative applications of ambient ionization MS.

Evaluation of organo-vermiculites as sorbent phases for solid-phase extraction of ibuprofen from water.

The study of ibuprofen (IBU) preconcentration was carried out making use of a homemade column for solid-phase extraction (SPE), using vermiculite (VT) or organo-vermiculites (OVTs) as sorbent phases. Aqueous samples (50.0 mL) percolated the column and IBU was sorbed onto the VT or OVT and then desorbed using acetonitrile. Employing this SPE system and OVT, calibration curves were generated for IBU, by spectrophotometric quantification using the α-naphthylamine method. R2 values higher than 0.9950 and LOD between 12 and 18 μg L-1 were observed, for real enrichment factors of 21 and 31, by using OVTs. The analytical protocol was applied to three water samples, which were spiked with IBU solutions to evaluate the precision and accuracy of the method. Recoveries between 77 and 110% at three different IBU concentrations and RSD lower than 18% were observed, even by using the spectrophotometric method. The protocol developed in this study demonstrated that the OVT was appropriate to work as a preconcentration phase for IBU determination in water samples.

A Novel and Fast Online-SPE-LC-MS/MS Method to Quantify Thyroid Hormone Metabolites in Rat Plasma.

Since the focus in regulatory toxicology has drifted toward the identification of endocrine disruptors, the improvement in determination of alterations in the thyroid hormone system has become more important. THs are involved in several molecular processes important for a proper pre- and postnatal development so that disturbances can inter alia lead to incorrect brain maturation and/or disturbed metabolic processes (thermogenesis or lipolysis). In this publication, a new automated online solid-phase extraction (SPE)-liquid chromatography (LC)-tandem mass spectrometry (MS/MS, xLC-MS/MS) is introduced which simultaneously analyzes total T4, T3, rT3, T2, and T1. Method validation parameters are presented, and the method was positively verified by analyzing control and PTU-treated rat plasma samples (time points day 7, 14, and 28) for their total TH content. The obtained results were compared to published results by using a radioimmunoassay method. The automated SPE system ensures a consistent unified sample preparation, and this method overall showed sufficient specificity and accuracy to detect the given analytes in rat plasma. For the preparation of 50 μL of rat plasma, the following LOQs were established: 0.020 nM for T1, 0.029 nM for T2, 0.023 nM for rT3 and T3, and 3.22 nM for T4. This method is suitable to assess the identification of mechanisms leading to adverse effects, such as disturbed TH metabolism and regulation.

Analytical quality by design using a D-optimal design and parallel factor analysis in an automatic solid phase extraction system coupled to liquid chromatography. Determination of nine PAHs in coffee samples

Optimizing a multi-residue analysis when using an automatic SPE (solid phase extraction) system and complex matrices becomes a difficult problem because of the large number of experimental factors that can influence the recovery of the analytes. Furthermore, in most cases, the conditions of the factors that enhance the response of one analyte are in conflict with those suitable for some others.In this work, AQbD (Analytical Quality by Design) is applied to the development of an analytical procedure based on automatic SPE coupled to HPLC-FLD in the determination of nine polycyclic aromatic hydrocarbons (PAHs) in coffee samples.Focussing on the SPE, the elution volume, the dry time, and volume in the wash stage, and the organic solvent (at two, three, three, and four levels, respectively) were considered.The first problem is to handle these four factors (control method parameters, CMPs) at different levels to optimize responses (critical quality attributes, CQAs). This task has been carried out using a D-optimal design that, starting from a full factorial design of four factors with 72 experiments, reduced this number to 19, maintaining the precision of the estimates, saving time and costs in the laboratory.The second problem is related to the choice of CQAs to apply the AQbD methodology. A complex matrix such as coffee contains impurities that interferes with the target analytes and may even coelute in the chromatographic determination. A PARAFAC decomposition allows avoiding this problem and uses the “second order advantage” to unequivocally identify each analyte. Then, the obtained sample loadings were used as responses. Specifically, each CQA is the difference between spiked and blank coffee samples. All these CQAs must be maximized.Once the experimental data were obtained, two alternatives were posed: on the one hand, the classical optimization based on the estimation of the effects of CMPs on the CQAs, and on the other hand, applying the AQbD methodology to construct the design space that allows to increase the knowledge of the automatic SPE system.Because the experimental domain of CMPs is discrete and the SPE system performs differently for each analyte, it is not possible to obtain the maximum of all CQAs at the same factor levels. Therefore, the design space of the CMPs is obtaining through the Pareto front of the non-dominated values of CQAs.The nine PAHs selected were phenanthrene (PHE), anthracene (ANT), fluoranthene (FLN), pyrene (PYR), chrysene (CHR), benzo[a]anthracene (BaA), perylene (PER), benzo[b]fluoranthene (BbF) and benzo[a]pyrene (BaP). European regulations amending foodstuff set maximum levels for BaP and the sum of the content of four compounds (PAH4): BaP, BaA, BbF and CHR.

Thiourea resole polymers for recovery of noble element

The recovery of noble elements from secondary source, industrial effluent, which are classified as high concentrated noble elements solution are very essential. Liquid-solid extraction systems are an attractive process used for the separation and purification of noble elements. For this purpose, a solid-phase extraction system was investigated for the recovery of noble metals (Au(III), Pd(II), and Rh(III)). Chelating resins were synthesized by a polycondensation reaction between phenolic thiourea monomers and formaldehyde under alkaline conditions. The resulting polymers were characterized and evaluated for their chelating properties with regard to noble metal sorption. Also, the selectivity of sorption of noble elements was studied in the presence of competitive elements that can be present in effluent waste, such as Zn, Cu, Ni, Fe, and Al. Here, we present a promising materials based on formo-phenolic thiourea resins as a potential candidate for high-capacity (> 350 mg/g for Au; > 50 mg/g for Pd; > 30 mg/g for Rh) and high-selectivity solid-liquid sorption of noble elements, particularly for Au.

Determination of Parabens and Phenolic Compounds in Dairy Products through the Use of a Two-Step Continuous SPE System Including an Enhanced Matrix Removal Sorbent in Combination with UHPLC-MS/MS.

Dairy products can be contaminated by parabens and phenolic compounds from a vast variety of sources, such as packaging and manufacturing processes, or livestock through feed and environmental water. A two-step continuous solid-phase extraction (SPE) and purification methodology was developed here for the determination of both types of compounds. In the first step, a sample extract is passed in sequence through an EMR-lipid sorbent and an Oasis PRiME HBL sorbent to remove fat and preconcentrate the analytes for subsequent detection and quantification by UHPLC-MS/MS. This method enabled the determination of 28 parabens and phenolic contaminant with excellent recovery (91-105%) thanks to the SPE sorbent combination used. The proposed method was validated through the determination of the target compounds, and was found to provide low detection limits (1-20 ng/kg) with only slight matrix effects (0-10%). It was used to analyse 32 different samples of dairy products with different packaging materials. Bisphenol A and bisphenol Z were the two phenolic compounds quantified in the largest number of samples, at concentrations over the range of 24-580 ng/kg, which did not exceed the limit set by European regulations. On the other hand, ethylparaben was the paraben found at the highest levels (33-470 ng/kg).

Biohybrid adsorbent for the preconcentration of lead and its determination in fruit juices by electrothermal atomic absorption spectrometry.

Fruit juices are one of the most non-alcoholic beverages consumed in the world. Essential elements and other nutrients present in fruit juices play an important role in human well-being. However, fruit juices may also contain potentially toxic elements at trace levels, causing health risks. The objective of this work was to develop an analytical methodology based on the preconcentration of lead using a new biodegradable hybrid material composed of Rhodococcus erythropolis AW3 bacteria and Brassica napus hairy roots. The biodegradable hybrid material was implemented in an online solid phase extraction system for the determination of lead in fruit juices by electrothermal atomic absorption spectrometry. Effects of critical parameters on lead retention were studied. Under optimal experimental conditions, extraction efficiency higher than 99.9% and an enrichment factor of 62.5 were achieved. The dynamic capacity of the biodegradable hybrid material was 36 mg/g, which favored the reuse of the column to at least 8 biosorption-desorption cycles. The limit of detection and quantification for preconcentration of 5 mL of sample were 5.0 and 16.5 ng/L lead, respectively. The relative standard deviation was 4.8% (at 1 µg/L lead and n = 10). The developed method was suitable to be applied for lead determination in different types of fruit juices.

On-line determination of the trace amount of cobalt(II) in real samples by flame atomic absorption spectrometry method after pre-concentration by modified polyvinyl chloride

This work reports a simple and sensitive on-line solid-phase extraction system for the pre-concentration and determination of a trace amount of Co(II (ions by flame atomic absorption spectrometry (FAAS). This method is based on the on-line retention of cobalt ions with polyvinyl chloride modified by 3-(2-thiazolylazo)-2,6-diaminopyridine in a mini-column system. The retained Co(II) ions were eluted with 1.0 mol L−1 HCl, and direct aspiration to flame atomic absorption spectrometry (FAAS) for an accurate determination of it. The important experimental parameters such as the solution pH, length of column (adsorbent mass), sample flow rate, solvent eluent, type and concentration of the eluent, and co-existing ion effects were investigated in detail and optimized. Under the optimum conditions, the calibration graph was linear over the concentration range of 2–150 µg L−1 for pre-concentration of 10.0 mL of the sample solution. The interassay precession (n = 6) was in the range of 1.8–5.2% at the concentration levels of 10.0, 50.0, 100.0, and 140.0 µg L−1. The limit of detection and enhancement factor were 1.3 µg L−1 and 40, respectively. The method was applied for determination of trace levels of Co(II) ions in different real samples such as tap water, waste water, vegetable, fruit, and drug with satisfactory results.

A sensitive, robust and high-throughput isotope dilution LC-MS/MS method for quantifying three folate forms in serum.

This study aimed to establish an isotope dilution LC-MS/MS method for the determination of folic acid, 5-formyltetrahydrofolate and 5-methyltetrahydrofolate in human serum. This method was then used to quantify these three folate forms in the healthy adult population and supplement users. A stable 96-well solid-phase extraction system was used to prepare serum samples. The highly sensitive method was established using a Shimadzu LCMS-8060NX. The linearity was good in the range of 0.1-10nmol/l for folic acid and 5-formyltetrahydrofolate and 1.0-100nmol/l for 5-methyltetrahydrofolate. The accuracy and precision were good. The method was sensitive, robust and high-throughput and could be used for the routine clinical monitoring of these three folate forms in the Chinese population.

Online micro solid phase extraction coupled with ultra-performance liquid chromatography-tandem mass spectrometry for trace analysis of endogenous plant hormones in Ulva linza.

Ulva linza (L.) is a species of green algae widely distributed in China. We aimed to establish a sensitive online analytical method for quantification of endogenous phytohormones in fresh minute seaweed samples. The method for quantification of endogenous plant hormones in fresh minute samples was developed based on a homemade online micro solid phase extraction (m-SPE) system coupled with an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) platform. The online m-SPE instrument injected the eluent of m-SPE directly onto the LC separation column, improving the utilization of samples and saving time. The m-SPE column, of which the effective size was 9.6 × 2mm i.d., was filled with 19 mg of C18 (10μm). Under optimized conditions, the limits of detection were 0.002-0.060 ng ml-1 for five plant hormones. The actual sample recoveries of phytohormones were 76.4-103.4% and the coefficients of variance were below 14.1%. The temporal distribution of these endogenous plant hormones of U. linza during different growth periods is described. The proposed online m-SPE method was successfully applied to quantification of endogenous acidic and alkaline plant hormones in U. linza. It provides important information for the further study of the physiological and ecological effects of plant hormones in lower algal species.

Automated rapid solid-phase extraction system for separation and preconcentration of trace elements using carboxymethylated polyethyleneimine-type chelating resin.

An automated system for the rapid separation and preconcentration of trace elements was developed. Carboxymethylated polyethyleneimine 600 (CM-PEI600), which is a partially carboxymethylated polyethyleneimine with a molecular weight of 600Da, was used as a chelating resin to quantitatively recover trace elements under high-flow-rate conditions. For accurately and precisely determining trace elements, even with a rough control of the sample and eluent flow volumes, an internal standardization technique was employed for the solid-phase extraction and separation. A recovery test of the deionized water-based sample solution was conducted using this system, and good results, with a recovery of 92% or higher, were obtained for 11 elements (Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, Ti, V, and Zn). Eight elements present in certified groundwater and wastewater reference materials (ES-L-1 and EU-L) were separated and preconcentrated using this system. Almost all the determined values were within their tolerance intervals, and no significant differences were observed between the determined and certified values, demonstrating the validity of this method. The time required for the separation and preconcentration using approximately 100mL of the sample solution was approximately 6.5min, and theoretically, the system could be used to preconcentrate 17 samples in an hour because extraction and elution could be conducted simultaneously using two cartridges packed with the chelating resin. Using this system equipped with cartridges packed with CM-PEI600 resin, solid-phase extraction and the separation of multiple elements were performed simultaneously, automatically, and rapidly, enabling the accurate and precise determination of trace elements in environmental water and inorganic salts even by rapidly flowing the sample solutions using peristaltic pumps. Compared to NOBIAS Chelate PA-1, a commercially available chelating resin, the CM-PEI600 resin can recover trace elements even under an extremely high flow rate of approximately 50mLmin-1.

Novel amino-functionalized magnetic metal-organic framework/layered double hydroxide adsorbent for microfluidic solid phase extraction: Application for vitamin D3

Vitamin D deficiency is highly prevalent worldwide, especially with limited sun exposure and sun avoidance. Thus, reliable monitoring of vitamin D levels in food and biological samples is vital for medicinal diagnosis. Herein, a potent method for the extraction and determination of vitamin D3 is presented using a microchip-based solid-phase extraction (SPE) device followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) detection. A new magnetic adsorbent based on Fe3O4 magnetic nanoparticles (MNPs) modified ZnFe layered double hydroxide (LDH)/2-aminoterephthalic acid-Zn2+ metal-organic framework (IRMOF-3) composite (IRMOF-3@MLDH) was successfully synthesized and fixed inside a rectangular micro-column (4 × 2 × 12 mm). The porous structure and high surface area of IRMOF-3@MLDH provide abundant adsorbing sites and make it a potent SPE adsorbent, with an exceptional ability to retain vitamin D3. The adsorption isotherm showed that the composite was highly efficient at extracting vitamin D3 with an extraction capacity of 126 mg g−1. The designed extraction microchip simplified the SPE process, paving the way for automated SPE systems. The developed method presented a broad linear range of 5–2000 ng mL−1, with a detection limit of 1.4 ng mL−1. In comparison to conventional silica-based adsorbents, a higher sensitivity was obtained in the determination of vitamin D3 using the IRMOF-3@MLDH adsorbent. The selectivity of the method was also satisfactory, enabling the measurement of vitamin D3 in food and blood samples with high recovery values in the range from 95.2 to 101%. Thus, the newly developed adsorbent and method offer an efficient alternative to the commonly used C18-based approach.

Study of degradation of norfloxacin antibiotic and their intermediates by natural solar photolysis.

In this work, the photolysis of the antibiotic norfloxacin (NOR) and the formation of its photodegradation products were studied using UV and solar radiation. Their extraction was also assessed in Milli-Q water and secondary effluents from a wastewater treatment plant. The photolysis of NOR was chromatographically monitored. The structure of each degradation product is related to the reaction of NOR with reactive oxygen species (ROS), as confirmed using radical quenchers and mass spectrometry. Additionally, the feasibility of extracting NOR and its degradation products was assessed using a commercial solid phase extraction system. Photolysis results showed the formation of five degradation products, generated under exposure to both types of radiation. The decays in NOR concentrations for the solar and UV treatments were adjusted to pseudo first-order kinetics with apparent constant values of ksolar = 1.19 × 10-3s-1 and kUV = 3.84 × 10-5s-1. Furthermore, the superoxide radical was the main participant species in the formation of the degradation products P3, P4, and P5. Species P1 and P2 do not need this radical for their formation. The presence of NOR in water opens the possibility of its photolysis by solar radiation. This work contributes to the understanding of the mechanisms that mediate its photodegradation, in addition to studying potential options for its determination and its photodegradation products in the sample treatment.

Automated and Rapid Easy-to-Use Magnetic Solid-Phase Extraction System for Five Heavy Metals in Cereals and Feeds.

A rapid, accurate, and ecofriendly pretreatment plays an extremely important role prior to ICP-MS for heavy metal analysis. In order to improve the pretreatment efficiency, a high-throughput and automatic magnetic solid-phase extraction of five heavy metals (Cd, Pb, Mn, Cu, and Zn) was carried out by a magnet-controlled pretreatment system with an ecofriendly diluted acid as an extracting agent and carboxyl-functionalized magnetic beads as a pretreatment material. Key conditions, including the pH, adsorption time, and eluent solution, were optimized. The time for purification and enrichment was only 8 min. The adsorption capacities of the carboxyl-functionalized magnetic beads were in the range of 152~426 mg g-1. The preconcentration factor of Cu was 40, and others were 200. In the optimal conditions, the limits of detection for Mn, Zn, Cd, Cu, and Pb by ICP-MS were 3.84, 2.71, 0.16, 11.54, and 6.01 ng L-1, respectively. The percentage recoveries were in the range of 80~110%, and the relative standard deviations were less than 3%. The developed method was in good agreement with traditional standard microwave digestion. Additionally, the designed system could simultaneously process up to 24 samples within 22 min, reducing the time to less than 1 min/sample. Thus, the proposed auto-MSPE-ICP-MS method was successfully applied to analyze five heavy metals in cereals and feeds with a simple operation and high precision, safety, and reliability.

Simultaneous Determination of Benzo(a)pyrene, Benzo(a)anthracene, Benzo( b)fluoranthene, and Chrysene in Tocotrienol Concentrates Using Dual Solid-phase Extraction and Gas Chromatography-Mass Spectrometry

Background: Polyaromatic hydrocarbons (PAHs) are a class of toxic compounds commonly found in edible vegetable oils as a result of contamination through food processing. Among the wide variety of PAHs existing in edible oils, benzo(a)pyrene (BAP), benzo(a)anthracene (BAA), benzo( b)fluoranthene (BBF), and chrysene (CHR) are commonly monitored due to their toxicity, carcinogenic and teratogenic properties. Materials and Methods: In this context, we described a combination of liquid-liquid extraction and dual cartridge solid-phase extraction (dSPE) system for the extraction of BAP, BAA, BBF, and CHR in palm oil derived tocotrienol rich fraction (T3RF), followed by their analysis using GC-MS operating in selected ion monitoring mode (SIM). Results: The separation was effected using a DB-5HT column (30 m × 0.25 mm × 0.25 μm) that can operate at a high temperature limit of 400 °C, which enables the separation of the PAHs in &lt; 28 min. The calibration curves were correlated within the range of 1.5-25 μg/ L, with detection limits (S/N: 3.3) of 0.48-1.35 μg/L, and relative standard deviations of ≤ 0.07% and ≤ 6.85% were achieved for intra-day retention times and peak areas. Conclusion: The proposed sample preparation and GC-SIM workflow greatly reduces interference caused by tocotrienol homologues and enables the quantitative determination of BAP, BAA, BBF, and CHR in T3RF and palm fatty acid distillates.