Mg Of Sorbent Research Articles

CLASSIFICATION OF COLORECTAL CANCER PATIENTS BASED ON SERUM MICRONUTRIENTS: AN EXPLORATORY INVESTIGATION

Abstract Introduction/Objective Colorectal cancer (CRC) is a growing global health challenge with a multifactorial etiology encompassing genetic susceptibility, nutrition, and inflammation in the bowel. To examine micronutrient status in CRC patients undergoing CRC resection. Methods/Case Report We performed a pilot case-control study including 13 consecutive CRC patients and 10 healthy controls (CTRL) comparing the serum levels of 29 micronutrients, namely Copper, Zinc, Selenium, Chromium, Manganese, Carnitine, Choline, Inositol, Methylmalonic acid (MMA), Vitamin (Vit) B1, Vit B2, Vit B3, Vit B5, Vit B6, Vit C, Vit A, Vit D3, Vit E, Vit K1, Vit K2 and the amino acids Serine, Valine, Leucine, Isoleucine, Asparagine, Glutamine, Arginine, Citrulline and Cysteine. The analysis of trace metals (copper, zinc, selenium, chromium, manganese) in serum was done using the Inductively coupled plasma mass spectrometry (ICP-MS) methodology using the Agilent 8900 QQQ instrument. The analysis of serum water-soluble and fat-soluble vitamins and amino acids was conducted using the LC/MS (Xevo-TQ-XS) mass spectrometer (WBA0127). Elution of the fat-soluble vitamins was performed using a solid-phase extraction system with an OASIS Prime HLB plate containing 10 mg of sorbent per well, in a Waters vacuum manifold equipped with a waste collection plate. Comparison among continuous biological variables was carried out by multivariate ANOVA model (MANOVA), accounting for the effect of sex and age Results (if a Case Study enter NA) After considering the effect of age and sex, copper, arginine, and cysteine were increased, while zinc, selenium, chromium, Vit B1, Vit K1, and Vit A were decreased in CRC patients in comparison with CTRL. Zinc levels perfectly predicted the diagnosis of CRC, and was associated with lymph nodes (pN), of the pTNM staging. Copper levels in serum was strongly associated with the pathological pTNM staging of CRC. Conclusion Though this is a preliminary study which needs confirmation with a larger longitudinal cohort, our results show that serum micronutrients are linked to tumor growth, likely caused by increased demand from tumor tissue associated with an aberrant cell proliferation and changes in the antioxidant function.

An ultrasound assisted dispersive micro solid-phase extraction and a composite ionic liquid-metal organic framework for sixteen polycyclic aromatic hydrocarbons analysis in fruit juice and environmental water samples

Aluminum-based metal organic framework composite containing ionic liquid was prepared and used as sorbent for extraction of sixteen polycyclic aromatic hydrocarbons in list of priority pollutants of United States Environmental Protection Agency before their analysis by gas chromatography/mass spectrometry. The dispersive micro solid-phase extraction method, known as a simple and fast method, was preferred as the extraction method. The optimized parameter conditions were 5 mL of sample solution, 10 min sonication by ultrasonic bath, 30 mg of sorbent, 30 °C extraction temperature, 0.1 mL of hexane as elution solvent with 5 min elution time. The suggested method presented that limit of detection and limit of quantification were in the range of 0.01–0.10 μg l-1, and 0.04–0.33 μg L-1, respectively. The intra-day and inter-day repeatability were within the ranges of 1.18–4.88 % and 1.02–5.06 %, respectively. The recoveries for polycyclic aromatic hydrocarbons in peach juice, cherry juice, tap water and rain water samples were obtained in the range of 84.9–99.9 % for spiked 5, 50 and 100 μg l-1 standard polycyclic aromatic hydrocarbons solution.

A fungal hyphae-derived biomass carbon for magnetic solid-phase extraction of the organochlorine pesticides in water samples, tea beverages, and Chinese traditional medicines before gas chromatography-tandem mass spectrometry determination

A magnetic biochar nanomaterial derived from fungal hyphae was introduced into the sample preparation field. The magnetic fungal hyphae-derived biomass carbon (MFHBC) could be produced by a controllable hydrothermal method. In order to obtain the best sorbent for magnetic solid-phase extraction (MSPE), the reaction conditions containing temperature, time and the consumption of fungal hyphae were investigated. A series of MFHBC materials were characterized by vibrating sample magnetometers, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. A material with a satisfactory saturation magnetization (21.58 emu g-1) and largest surface area (88.06 m2 g-1) was selected as the sorbent to extract ten typical organochlorine pesticides (OCPs). The extraction conditions were optimized as 20 mL of sample solution with 70 mg of sorbent and 2.0 g of NaCl oscillated at 50 °C for 5.0 min. And the optimum desorption was performed by oscillating sorbent in 1.0 mL acetonitrile for 5.0 min. Then, the MFHBC-based MSPE-GC–MS/MS methods were established for different samples including water samples, tea beverages, and Chinese traditional medicines. The linearities were 10–2500 ng L−1 or 100–25,000 ng kg−1, and the limits of detection were 0.3–13.9 ng L−1 for water sample, 0.1–9.7 ng L−1 for tea beverage samples, 0.1–21.4 ng L−1 for Shenqi Fuzheng injection samples, and 7.2–278.3 ng kg−1 for Astragali Radix decoction pieces. Except for satisfactory repeatability (RSDs ≤13.8%) in intra-day and inter-day tests (n = 3), the reproducibility (RSDs ≤13.5%, n = 3) of MFHBC was acceptable. The methods were applied in the determination of OCPs from above real samples, with the recoveries of 80.5–117.2% and the RSDs (n = 3) <8.9%. The methods were suitable in the sensitive determination of OCPs from simple to complex matrix samples.

Activated carbon from avocado seed as sorbent phase for microextraction technologies: activation, characterization, and analytical performance.

According to green analytical chemistry principles, the use of agricultural byproducts as sorbent phases is an interesting topic due to their lignocellulosic origin, as they are biodegradable and inexpensive. To the best of our knowledge, this is the first study in which avocado seed and avocado seed activated carbon are proposed as sustainable sorbents for solid-phase microextraction technologies, which were used to assess the proof of concept. Rotating disk sorptive extraction (RDSE) was used as a model technology and ibuprofen (Ibu) and 1-hydroxy-ibuprofen (1-OH-Ibu) as representative analytes. It was found that activated carbon (AC) prepared at 600°C with an impregnation ratio (raw material/activating agent (ZnCl2), w/w) of 1:1.2 had better extraction efficiency than other ACs obtained at different temperatures, impregnation ratios, and activating agents (K2CO3). Characterization revealed several differences between natural avocado seed, biochar prepared at 600°C, and selected AC since the typical functional groups of the natural starting material begin to disappear with pyrolysis and increasing the surface area and pore volume, suggesting that the main interactions between analytes and the sorbent material are pore filling and π-π stacking. By using this AC as the sorbent phase, the optimal extraction conditions in RDSE were as follows: the use of 50mg of sorbent in the disk, 30mL of sample volume, pH 4, 90min of extraction time at a rotation velocity of the disk of 2000rpm, and methanol as the elution solvent. The extracts were analyzed via gas chromatography coupled to mass spectrometry (GC-MS). The method provided limits of detection of 0.23 and 0.07µg L-1 and recoveries of 81% and 91% for Ibu and 1-OH-Ibu, respectively. When comparing the extraction efficiency of the selected activated carbon with those provided by Oasis® HLB and C18 in RDSE, nonsignificant differences were observed, indicating that avocado seed activated carbon is a suitable alternative to these commercial materials.

Bioinspired composite packed in blunt needles, integrated microextraction and determination of oxycodone and naloxone in saliva by substrate spray mass spectrometry

BackgroundOpioids are effective painkillers used for medical purposes. Their prolonged ingestion can provoke some side effects (including overdose or constipation) that are minimized by using opioid antagonists (e.g., naloxone). The rapid determination of opioids and their antagonists in biosamples is essential for an effective medical treatment. The direct combination of sample preparation and mass spectrometry (MS) fits well in this scenario. It can speed up the analysis achieving a good selectivity, which relies on the sample preparation and MS, and sensitivity levels. ResultsThis article presents a novel substrate-spray mass spectrometry interface based on a polydopamine-cotton (PDA-Cel) composite hosted inside the inner diameter of a 14-gauge blunt needle to determine oxycodone and naloxone in saliva samples. The needle is used as a microextraction device and a substrate for mass spectrometric analysis. The lack of sharpness of the 14-gauge (14G) blunt needles challenges the formation of the electrospray (ESI), and a commercial 10 μL pipette tip is proposed as a simple solution to this shortcoming. Under the optimum parameters, the proposed method was validated, obtaining limits of detection lower than 0.6 μg L−1, linear range up to 200 μg L−1, and linearity better than 0.9915. Relative standard deviation (RSD) and relative recoveries (RR) were studied at three different concentration levels (2, 40, and 200 μg L−1). RSD values were better than 20.7 %, and RR ranged from 90 to 114 %. Finally, a positive sample from a patient under medical treatment was analyzed. Significance and novelty14G blunt needles have been demonstrated as effective extraction devices due to their low price (<0.15 € per extraction unit), their better safety (avoiding finger pricking), and their higher hosting capacity (up to 8 mg of sorbent). The conductivity of stainless steel permits their use as electrospray emitters, making their direct combination to MS easier. The large variety of fibrous sorbents makes this approach versatile enough to be adapted to other analytical problems.

Microextraction experimental and forcefield theoretical modelling study on exploring a silica-enriched oil palm frond biomass for the determination of polycyclic aromatic hydrocarbons in Psidium guajava

In this study, a dispersive micro-solid phase extraction (D-µ-SPE) based on oil palm frond-based silica (OPF-SiO2) sorbent was investigated for the determination of four polycyclic aromatic hydrocarbons (PAHs) in Psidium guajava integrated with high-performance liquid chromatography (HPLC-DAD). The physicochemical characterization of the acid-treated and thermally extracted OPF-SiO2 by FTIR showed peaks at 806 cm−1 and 446 cm−1 allotted to siloxane stretching vibrations and siloxane terminating vibrations, while the FESEM spectrum of EDX analysis corroborated the presence of silicon in OPF-SiO2. Likewise, the XRD diffractograms displayed prominent peaks at 2θ = 24°, indicating a predominantly amorphous silica structure. The XRF analysis further corroborated this result, which revealed that silica constituted 78 % of the major elemental composition. The established optimized condition of D-µ-SPE extraction of PAHs required 60 mg of sorbent, an extraction time of 15 min using acetonitrile as the elution solvent, and a 5 min desorption time. The prepared sorbents exhibited a high affinity for PAHs through van der Waals and hydrogen bonding. The D-µ-SPE was linear between 50 and 5000 µg kg−1 for naphthalene, fluorene, anthracene, and pyrene (R2 = 0.9921–––0.9997). The RSDs were acceptable for intraday (0.65–1.52 %, n = 3) and interday (0.60–1.92 %) analyses, coupled with low detection limits (2.33–4.90 µg kg−1) and satisfactory relative recovery (95.05–108.88 %). The experimental results supported the subsequent forcefield theory calculations for the PAHs and the OPF-SiO2 composite’s interactions. Analytical GREEnness (AGREE) with a metric score 0.60 indicates that the developed approach is green.

Efficient extraction and analysis of precious metals with a conducting polymer modified magnetic sorbent material

Polymerization of pyrrole-1-carbodithioic acid on silica coated Fe3O4 nanoparticles created the magnetic sorbent, PPy-CS2@SiO2@Fe3O4, for extraction and analysis of precious metals. PPy-CS2@SiO2@Fe3O4 is an air stable, granular composite readily dispersible in water and suitable for magnetic solid-phase extraction of Ru, Rh, Ir, Pd, Pt and Au. Maximum sorption and recovery was achieved at pH 6, 15 mg of sorbent and a 15 min extraction time, and a 4 mL desorption solution consisting of 2 M HNO3 and 0.5 M thiourea. Limits of detection (0.02 to 0.08 µg L−1), linear dynamic ranges (0.5 to 1000 µg L−1) and relative standard deviations (1.3 to 5.2%) were determined. Extraction with PPy-CS2@SiO2@Fe3O4 was not affected by a 400-fold excess of co-existing metals, allowing extraction from a complex chemical reaction mixture and produced water. Bulk sorption capacities for Pd2+ and Au3+ were 163.0 and 132.7 mg g−1, respectively, indicating larger scale extractions are possible.

Determination of Aflatoxins in Milk by PS-MWCNT/OH Composite Nanofibers Solid-Phase Extraction Coupled with HPLC-FLD.

In this work, a sensitive analytical method based on packed-nanofiber solid-phase extraction (PFSPE), after derivatization with trichloroacetic acid and high-performance liquid chromatography with a fluorescence detector (HPLC-FLD), has been established for the determination of aflatoxins (AFs) in milk. Polystyrene polymeric multi-walled carbon nanotube (PS-MWCNT/OH) composite nanofibers were fabricated by electrospinning and used to prepare homemade extraction columns. The extraction efficiency of the HPLC-FLD analysis method was sufficiently investigated and validated. After the implementation of optimal conditions, all of the analytes were separated efficiently and the components of the milk matrix did not disturb the determination. The obtained linear ranges of the calibration curves were 0.2-20 ng/mL for AFTB1 and AFTG2, 0.1-10 ng/mL for AFTB2, and 0.4-40 ng/mL for AFTG1. The recoveries ranged between 80.22% and 96.21%. The relative standard deviations (RSDs) for the intra-day and inter-day results ranged from 2.81-6.43% to 3.42-7.75%, respectively. Generally, 11 mg of sorbent and 200 μL of elution solvent were used to directly extract all of the AFs from the milk matrix. Reported herein is the first utilization of PS-MWCNT/OH-PFSPE HPLC-FLD to simultaneously analyze the occurrence of aflatoxins in milk.

Determination of selected pesticides by GC-FID after CNO/MOF nanocomposites-based dispersive solid phase extraction coupled with liquid microextraction

A nanocomposite based on carbon nano onion and ZIF67 metal-organic framework has been synthesized and was characterized by X-ray diffraction spectroscopy, scanning electron microscopy, and Furrier-transformed infrared spectroscopy. The extraction performance of organochlorine and organophosphorus pesticides by the synthesized nanocomposite was evaluated. The prepared sorbent was used as a sorbent in the dispersive solid-phase extraction method, and then dispersive liquid-liquid microextraction was contacted for more cleanup and preconcentration. The final extracted analytes were analyzed by gas chromatography. In this combined method, the analytes were extracted with only 10 mg of sorbent and 20 μL of tetrachloride carbon as extraction solvent. The affecting parameters on the extraction efficiency were thoroughly investigated by one parameter at a time approach. The precision of the method was measured through intra-day and inter-day (n = 5) repetitive experiments that showed RSD values lower than 6.9 %. The combination of the optimized dispersive solid-phase extraction with dispersive liquid-liquid microextraction followed by gas chromatography provided a powerful procedure for pesticide analysis.

Modified Polysulfone Nanofibers for the Extraction and Preconcentration of Lead from Aqueous Solutions.

Since lead is a highly toxic metal, it is necessary to detect its presence in different samples; unfortunately, analysis can be complicated if the samples contain concentrations below the detection limit of conventional analytical techniques. Solid phase extraction is a technique that allows the carrying out of a pre-concentration process and thus makes it easy to quantify analytes. This work studied the efficiency of sorption and preconcentration of lead utilizing polysulfone (PSf) fibers grafted with acrylic acid (AA). The best conditions for Pb(II) extraction were: pH 5, 0.1 mol L-1 of ionic strength, and 40 mg of sorbent (70% of removal). The sorbed Pb(II) was pre-concentrated by using an HNO3 solution and quantified using flame atomic absorption spectrometry. The described procedure was used to obtain a correlation curve between initial concentrations and those obtained after the preconcentration process. This curve and the developed methodology were applied to the determination of Pb(II) concentration in a water sample contained in a handmade glazed clay vessel. With the implementation of the developed method, it was possible to pre-concentrate and determine a leached Pb(II) concentration of 258 µg L-1.

Green synthesis of bio-functionalised copper nanoparticles using cinnamon extract and its application as a fast and high-efficiency sorbent for the removal of Janus Green B

ABSTRACT In this study, a biocompatible sorbent based on copper nanoparticles was synthesised from the extract of cinnamon. The sorbent was characterised by X-ray diffraction, field emission electron microscopy, and Fourier transform infrared spectroscopy. Then, the capability of the prepared sorbent was evaluated for the removal of the Janus Green B (JGB) azo dye from the aqueous media. Initially, the sorbent showed a very fast sorption rate that gradually became slower. Thus, with an initial dye concentration of 200 mg L−1, pH of 6.0, and 10 mg of sorbent, about 84% of the dye is removed in 2 minutes, and the maximum removal efficiency is achieved after 15 minutes (>95%). The sorption data were best fitted with the Langmuir isotherm model with a maximum sorption capacity of 193.62 mg g−1. A pseudo-second-order kinetic model was suitable for explaining the JGB dye sorption rate on the sorbent.

Preparation of Fe3O4-Reduced Graphene-Activated Carbon from Wastepaper in the Dispersive Solid-Phase Extraction and UHPLC-PDA Determination of Antibiotics in Human Plasma

In this work, a sorbent was prepared from wastepaper samples enriched with iron oxide particles and graphene oxide and used in the solid phase extraction of antibiotics. The precursor underwent a carbothermal reduction to promote the formation of paramagnetic phases useful for the recovery of the sorbent during the analysis, and to disperse and fix graphene and the iron oxide in a durable way throughout the cellulose structure. Characterizations were carried out to evaluate the composition (Raman, XRD and EDX) and the morphological structure (SEM) of the material. A UHPLC-PDA method was developed for the simultaneous determination of antibiotics from different drug families (carbapenems, fluoroquinolones, β-lactams) using a 120 SB-C 18 poroshell column (50 × 2.1 mm I.D., 2.7 um particle size) and a mobile phase consisting of 10 mM acetate buffer at pH 5 (Line A) and acetonitrile (Line B) both containing 0.1% of triethylamine. A gradient elution was used for the separation of the analytes, while for the quantitative analysis each analyte was determined at its maximum wavelength. Several experiments were carried out to evaluate the influence of different parameters involving the dispersive magnetic solid phase extraction of these analytes. Samples were extracted using 25 mg of sorbent at pH 5 and desorbed in 5 min using methanol. We report herein on some of the outstanding advantages of using carbon-based sorbent, such as lower toxicity, scalability, improved absorption capacity, target selectivity and stability in acidic medium. Moreover, from the results obtained it is evident that, despite the use of some recycled materials, the performances obtained were comparable or even superior to the methods reported in the literature.

Senzor na bazi mezoporozne silike za kolorimetrijsko određivanje boje Basic Yellow 28 u vodenim rastvorima

The textile industry is one of the largest water-consuming industries in the world. The wastewater generated by the textile industry is a major source of pollution, containing mostly dyes, but also detergents, and heavy metals. Since dyes can have a negative impact on the environment, human and aquatic life, it is really important to find proper solutions for removal of these pollutants from wastewater. In addition, special attention is given to the discovery of new and fast "in situ" methods for identification and quantification of pollutants from wastewater. In this paper, SBA-15, mesoporous silica material, was used as sorbent for removal of Basic Yellow 28 from aqueous solutions. In addition, colored SBA-15 after sorption process was subjected to image analysis, to evaluate if it was possible to quantify sorbed dye on sorbent based on intensity of SBA-15 coloration. The obtained results revealed that SBA-15 could remove 99% of dye within 5 min. The highest efficiency of dye removal was at pH8, using 200 mg of sorbent. According to the Langmuir isotherm model, the theoretical maximum sorption capacity was 909 mg/g. Image-Pro software confirmed that it would be possible to quantify sorbed dye onto SBA-15 with accuracy of 0.98. Overall, SBA-15 demonstrated to be efficient sorbent in removal of Basic Yellow 28 from water, but also to be potential carrier as a sensor for detection of colored pollutants in water.

Selective solid-phase extraction of atrazine from agricultural environmental water samples using high permeability nanoporous carbon derived from melamine-based polybenzoxazine followed by HPLC-UV

ABSTRACT For the first time, a highly permeable nanoporous carbon derived from melamine-based polybenzoxazine (NPC-PBZ-m) was used as the solid-phase extraction sorbent for trace analysis of atrazine (ATZ) herbicide in environmental water samples as a pre-treatment to enhance detection for high-performance liquid chromatography. Extraction performance was investigated using an agricultural field matrix-water sample. The parameters affecting the solid-phase extraction efficiency were carefully investigated. The optimisation conditions were determined as 200.0 mg of sorbent with an adsorption flow rate of 10.0 mL min−1, an elution flow rate of 1.0 mL min−1, and an elution volume of 3.0 mL. Moreover, it was not necessary to adjust the pH of the sample. Under these optimised extraction conditions, good linearity between 5.00 and 30.0 µg L−1 was achieved along with a limit of detection (LOD) of 1.25 µg L−1 and a limit of quantification (LOQ) of 3.79 µg L−1. Furthermore, the reusability of the NPC-PBZ-m column was found up to 8 cycles making it a new cost-effective material for herbicide enrichment. Finally, this developed method was successfully applied to analyse ATZ in water samples from rice fields, fish farms, and natural canal water, with 98–117% relative recoveries. These results indicate that NPC-PBZ-m with our proposed method is feasible and demonstrates its potential application as an effective adsorbent for herbicide enrichment.

Green methodology based on active air sampling followed by solid phase microextraction and gas chromatography-tandem mass spectrometry analysis to determine hazardous substances in different environments related to tire rubber

A fast, efficient, and simple air sampling methodology was developed to study a high number of volatile and semivolatile organic compounds in air above tire rubber materials and surfaces made of recycled tire rubber. The proposed method, based on active sampling (solid-phase extraction, SPE) using a small quantity of sorbent material (25 mg) followed by solid-phase microextraction (SPME) and gas chromatography-tandem mass spectrometry analysis, was developed with the aim of determining 40 organics substances including polycyclic aromatic hydrocarbons (PAHs), plasticizers, antioxidants, and vulcanization agents. An experimental design was carried out to study the influence of main factors such as type of SPME fibre, solvent addition, headspace volume, stirring, as well as the factor interactions. Method performance showed good linearity in a broad concentration range (0.05 to 200 ng m−3, for most compounds), with coefficients of determination (R2) higher than 0.9900. Whole method precision (≤ 16 %) and accuracy were also satisfactory, obtaining quantitative recoveries (mean values between 80 and 110 % in most cases). Limits of detection and quantification have also been calculated, yielding values of sub ng m−3 for most compounds. The validated method was applied to outdoor and indoor air environments including playgrounds, football pitches and warehouses showing the presence of most target compounds in the samples achieving high levels for some PAHs (concentrations up to 51 ng m−3), benzothiazole (BTZ), diisobutyl- dibutyl- and di-(2-ethylhexyl)- phthalate, among others, reaching concentrations up to hundreds of ng m−3 (BTZ). This is the first time that the combination of techniques SPE and SPME is applied for these families of chemicals, and it is also the first time that this approach is proposed for the simultaneous multiclass compound extraction of substances of different chemical families. The whole sampling and extraction procedure is performed in a short period of time (61 min) allowing high throughput. The elimination of the use of organic solvents and waste generation by using only 25 mg of sorbent and a SPME fibre than are both reused makes the method sustainable and in consonance with the principles of the green chemistry. The method can be implemented in any routine lab and easily automated using a SPME autosampler.

Sludge-based activated carbon and its application in the removal of perfluoroalkyl substances: A feasible approach towards a circular economy

This study explores the recovery of resources and energy from sewage sludge through the production of sludge-based activated carbon (SBAC) considering circular economy principles. The SBAC production costs were estimated under three scenarios considering various sludge dewatering/drying schemes to determine the production feasibility and its role in the circular economy. SBAC was tested in the removal of a mixture of nine commonly detected poly- and perfluoroalkyl substances (PFASs) in environmentally relevant concentrations of ∽50 μg/L in comparison to commercially available activated carbon (AC) using 5 mg of sorbent and 5 mL of a nine-PFAS mixture in deionised water. SBAC can be produced at approximately 1.2 US $/kg, which is substantially lower than the average production cost of commercial AC of >3 US $/kg. A net revenue ranging from 2 to 7 US $/kg SBAC was estimated by recycling the produced non-condensable gases and bio-oil to produce energy and selling the SBAC. Batch adsorption tests showed that the PFASs removal of SBAC was superior to that of granular AC and similar to that of powdered AC, reaching >91% to below the detection limit. The kinetics tests revealed that adsorption by SBAC and AC occurred within 15 min. The overall results demonstrate the potential of SBAC as an effective sorbent for PFASs, achieving waste-to-resources circular economy via resource and energy recovery from sewage sludge, eliminating sludge disposal and contaminant-leaching to the environment, and in enhancing the quality of wastewater effluent before discharge.

SORPTION-LUMINESCENT DETERMINATION OF OROTIC ACID IN MEDICINAL DRUGS

Luminescent properties of orotic acid (vitamin B13), known bioactive substance, have been evaluated in this research. It has been shown that inside a coordination complex of orotic acid with terbium (III) an intermollecular excitation energy transfer from a ligand to a lanthanide ion occurs which causes sensitization of terbium (III) ion luminescence. Intensity of the terbium (III) ion luminescence (ILum) increases in the presence of anionic and cationic surfaceactive agents as a result of displacement of water molecules from coordination sphere of the complex. As a consequence of this process, a non-radiative deactivation of excitation energy decreases and more efficient excitation energy transfer from a ligand to a lanthanide ion occurs. It has been established that after absorption of analyte of interest onto a polymer matrix of a solid phase extraction sorbent with subsequent increasing of its molecular rigidity more efficient excitation energy transfer is observed followed by elevation of luminescence (ILum) intensity of the coordination complex being studied. Intensity of luminescence of coordination complex of orotic acid with terbium (III) in the form of a sorbate salt has been estimated involving different types of sorbents (Phosphalugel, SFG-75, Calflo E, Celite 545, Silicagel Merck). Most suitable results have been achieved by the use of Silica gel Merck as a solid-phase matrix (sorbent). The removal rate of the complex from the solution in this case reaches to 97%. The most effective conditions for determination of orotic acid have been specified. The highest values of luminescence intensity is obtained by conducting of sorption using 5 mL of solution and 100 mg of sorbent. Luminescence intensity of the complex in the form of a sorbate salt, during a sorption process, increases in presence of ethonium, cationic dimeric surface-active agent. Decrease in luminescence intensity of the complexes in the form of a sorbate salt in presence of other surface-active agents may be caused by solubilization of the complex in the solution and thereby reduced level of its sorption. On the basis of presented research work a new analytical procedure has been developed for the solid-phase luminescence determination of orotic acid and orotic acid salts in pharmaceutical drugs. Determination of orotic acid salts has been performed in pharmaceutical drugs ‘Magnerot’ (magnesium orotate) and ‘Potassium orotate’. The proposed analytical procedure for determination of orotic acid salts is remarkable by good metrological characteristics and relative simplicity of performance. The relative standard deviation, Sr, is 3,6 - 4,3%.

Synthesis and Characterization of Poly(pyrrole-1-carboxylic acid) for Preconcentration and Determination of Rare Earth Elements and Heavy Metals in Water Matrices.

Pyrrole was N-functionalized with solid carbon dioxide followed by chemical polymerization to create a new air-stable, granular, and water-insoluble sorbent, poly(pyrrole-1-carboxylic acid) (PPy-CO2). PPy-CO2 exhibited enhanced affinity for the sorption of metal ions compared to unfunctionalized PPy due to the incorporation of carboxylate functional groups directly onto the polymer backbone. As a freestanding sorbent material, immobilization to an additional solid support is not needed. Sorption, and therefore preconcentration, occurs simultaneously to achieve efficient removal and recovery of metal ions by a pH-dependent sorption-desorption mechanism. PPy-CO2 was evaluated on the analytical scale for the solid-phase extraction of a range of metal ions and found to efficiently preconcentrate rare earth elements (REEs), Th, and heavy metals (Cr, Fe, Cd, and Pb), which allowed quantitation by inductively coupled plasma mass spectrometry (ICP-MS). The impact of sorption parameters, such as solution pH, amount of sorbent, and sorption time, and the effect of desorption flow rate for recovery were investigated and optimized using ultrasound-assisted dispersive solid-phase extraction (UAD-SPE) with ICP-MS analysis. Maximum efficiency for sorption and recovery of most metal ions was achieved at a solution pH of 6.0, 10 mg of sorbent, a sorption time of 5 min, and desorption conditions of 1 mL of 2 M nitric acid applied at a flow rate of 0.25 mL min-1. Detection limits for REEs and Th ranged from 0.2-3.4 ng L-1 for REEs and Th and 0.9-5.7 ng L-1 for heavy metals. Linear ranges from 0.1-1000 μg L-1 for REEs and 0.1-500 μg L-1 for heavy metals and Th were also observed. PPy-CO2 successfully preconcentrated and facilitated the determination of the targeted metal ions in water matrices of varying complexity, including tap water, well water, river water, and produced water samples. These results indicate the potential application of PPy-CO2 for larger-scale recovery and removal of valuable or hazardous metal ions.

Ionic imprinted polymer – Vortex-assisted dispersive micro-solid phase extraction for inorganic arsenic speciation in rice by HPLC-ICP-MS

This study combines ultrasound-assisted extraction and vortex-assisted dispersive micro-solid phase extraction using an ionic imprinted polymer as a selective sorbent for rapid isolation and pre-concentration of inorganic arsenic species (As(III) and As(V)) in extracts from rice samples prior to their determination by high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry. All factors affecting the ultrasound assisted extraction of the species from rice (ultrasound amplitude, sonication time and sonication mode) and their selective pre-concentration by ionic imprinted polymer-based vortex-assisted dispersive micro-solid phase extraction (sorbent amount, extract pH, vortex extraction time and speed, eluting solution and vortex elution time and speed) were optimized. The analytical performance of the procedure was studied at optimum conditions: ultrasound continuous sonication at 40% amplitude for 2.0 min using 1:1 methanol/ultrapure as an extractant, 50 mg of sorbent, extract pH at 8.0, vortex loading at 1000 rpm for 1.0 min, and elution with ultrapure water by vortexing at 1000 rpm for 1.0 min, pre-concentration procedure which leads to a pre-concentration factor of 10. The limits of detection obtained for As (III) and As (V) were 0.20 and 0.41 μg kg−1, respectively, and were well below the maximum levels established by the European Union in rice and rice containing products. The method was found to be precise (intraday and interday relative standard deviations ≤ 11%) and selective. The accuracy was confirmed by analysing the ERM-BC211 (rice, As species) certified reference material, and the method was successfully applied to commercial rice samples.

Dispersive solid-phase microextraction with arginine-functionalized magnetic nanocomposite as the sorbent for separation and preconcentration of aspartame and optimization using response surface methodology

In this study, the surface of magnetic dialdehyde starch nanocomposite has been modified with arginine amino acid (Arg) and employed as an adsorbent for the enrichment of aspartame (ASP) in different real samples. Magnetite dispersive solid-phase microextraction (MDSPME), which had been combined with spectrophotometry, has been used to determine the extracted aspartame. The Plackett–Burman design has been employed to investigate the influence of main parameters including the amount of salt, sample volume, amount of sorbent, dispersive solution volume, desorption, and extraction time, and central composite design has been used to obtain the optimum condition in MDSPME method. Under optimum conditions, 15 ml of sample volume, 1.5 ml of ethanol as dispersive solvent, 10 min of extraction time, 15 min of desorption time, 10 mg of sorbent, and 0 w/v % of salt, the calibration graph has been observed to be linear in a concentration range of 2–15 µg ml−1, while the limit of detection has been 0.064 µg ml−1. The relative standard deviations of 3.64 and 4.12 have been obtained at 8 µg ml−1 level of aspartame for the intra- and inter-day analysis. In addition, the enrichment factor has been about 128. This procedure has been successfully utilized for distinguishing the existing aspartame in two kinds of beverage that had been procured from local markets and drinkable water.