Anion-exchange Cartridge Research Articles

Determination of a comprehensive set of drugs of abuse, metabolites and human biomarkers in wastewater using passive sampling followed by UHPLC-MS/MS analysis

Passive sampling of wastewater using polar organic chemical integrative samplers (POCIS) is an interesting and cost-effective strategy for the quantification of biomarkers of drugs of abuse consumption in epidemiological studies. Particularly when combined with sensitive analytical method as ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS), POCIS sampling allows the long-term and sensitive determination of a wide range of analytes. In this study, a comprehensive analytical method integrating POCIS sampling, selective solid-phase extraction (SPE) of POCIS extracts, and analysis by UHPLC-MS/MS was developed and successfully validated for 12 biomarkers of substance use, with potential use in wastewater-based epidemiology. Chromatographic separation was achieved in 11 min. The assay has a wide liner range, with lower limits of quantification of 5 ng g−1 of POCIS sorbent. The selective SPE procedure, combining both cation and anion exchange cartridges, resulted in low matrix effects (-19.3 to 22.8% for compounds with a deuterated analog internal standard and 33.4 to 42.5% for anhydroecgonine methyl ester) and high extraction yields (93.4 to 106.4%). The lab-made POCIS sampler with Oasis® HLB sorbent was adequately calibrated for 9 compounds (4 drugs of abuse, 4 drug metabolites, and 1 human non-drug lifestyle markers). The method was applied in a wastewater treatment plant in Brazil, with continuous monitoring for 392 days in 2020–2021. The highest calculated wastewater concentration among drugs of abuse and metabolites was found for benzoylecgonine (431.5 ± 190.6 ng L-1), followed by 11-nor-9-carboxy-Δ9-THC (58.3 ± 21.1 ng L-1). The assay described in this study can be used as an effective tool to monitor the presence of relevant drug consumption biomarkers in wastewater, a relevant epidemiologic strategy currently limited due to the sophisticated infrastructure needed for representative sampling.

Study of the automated synthesis of the radiopharmaceutical fluoroestradiol-18F

Approximately 75% of breast cancer cells express estrogen receptor positive, being the second leading cause of cancer death among women worldwide with an incidence of 25% per year. 16α-[18F]-fluoro-17β-estradiol, FES-18F, is a radiopharmaceutical that binds to estrogen receptors enabling the acquisition of molecular images for non-invasive diagnosis of primary and metastatic breast cancer using PET-CT. The objective of this work was to study the synthesis of FES-18F in the GE TRACERlab® MXFDG module, using the chemical kit and the ABX® disposable cassette, and to determine the process yield and the analytical parameters to be used in the routine production of this radiopharmaceutical. Automated synthesis occurs in 75 minutes and includes percolation of [18F-] fluoride into an anion exchange cartridge, cartridge elution, 3-step azeotropic drying, labeling using precursor 3-methoxymethyl-16β,17β-epiestriol-O-cyclic sulfone (MMSE) and a hydrolysis step. Product purification is done in the module using solid phase extraction (SPE) cartridges. The radiochemical yield was reproductive, regardless of fluor-18 activity at entry into the module, and the results of quality control tests suggest that the radiopharmaceutical meets the criteria established for other fluor-18-labelled radiopharmaceuticals that have monographs in official compendiums. In vivo biodistribution studies in healthy animals and with a tumor model developed with MCF-7 cells, demonstrated radiopharmaceutical uptake in excretory organs and specificity for breast tumor cells.

One-pot and one-step automated radio-synthesis of [18F]AlF-FAPI-74 using a multi purpose synthesizer: a proof-of-concept experiment

BackgroundFibroblast activation protein (FAP) is overexpressed in the stroma of many types of cancer. [18F]AlF-FAPI-74 is a positron emission tomography tracer with high selectivity for FAP, which has already shown high accumulation within human tumors in clinical studies. However, [18F]AlF-FAPI-74 radiosynthesis has not been optimized using an automated synthesizer. Herein, we report a one-pot and one-step automated radiosynthesis method using a multi purpose synthesizer.ResultsRadiosynthesis of [18F]AlF-FAPI-74 was performed using a cassette-type multi purpose synthesizer CFN-MPS200. After the recovery rate of trapped [18F]fluoride onto the anion-exchange cartridge using a small amount of eluent was investigated manually, a dedicated [18F]AlF-FAPI-74 synthesis cassette and synthesis program for one-pot and one-step fluorination was developed. The solutions for the formulation of [18F]AlF-FAPI-74 synthesized using this were evaluated to obtain stable radiochemical purity. The recovery rate of [18F]fluoride with only 300 µL of eluent ranged 90 ± 9% by introduction from the male side and elution from the female side of the cartridge. In automated synthesis, the eluted [18F]fluoride and precursor solution containing aluminum chloride were mixed; then, fluorination was performed in a one-pot and one-step process at room temperature for 5 min, followed by 15 min at 95 °C. As a result, the radioactivity of [18F]AlF-FAPI-74 was 11.3 ± 1.1 GBq at the end of synthesis from 32 to 40 GBq of [18F]fluoride, and its radiochemical yield was 37 ± 4% (n = 10). The radiochemical purity at the end of the synthesis was ≥ 97% for all formulation solutions. When the diluent was saline, the radiochemical purity markedly decreased after 4 h of synthesis. In contrast, with phosphate-buffered saline (pH 7.4) or 10 mM phosphate-buffered saline (pH 6.7) containing 100 mg of sodium ascorbate, the radiochemical purity was stable at 97%. Non-radioactive AlF-FAPI-74 and total impurities, including non-radioactive AlF-FAPI-74, were 0.3 ± 0.1 µg/mL and 2.8 ± 0.6 µg/mL. Ethanol concentration and residual DMSO were 5.5 ± 0.2% and 21 ± 6 ppm, respectively.ConclusionsWe established a one-pot one-step automated synthesis method using a CFN-MPS200 synthesizer that provided high radioactivity and stable radiochemical purity for possible clinical applications.

Insights into Elution of Anion Exchange Cartridges: Opening the Path toward Aliphatic 18F-Radiolabeling of Base-Sensitive Tracers.

Aliphatic nucleophilic substitution (SN2) with [18F]fluoride is the most widely applied method to prepare 18F-labeled positron emission tomography (PET) tracers. Strong basic conditions commonly used during 18F-labeling procedures inherently limit or prohibit labeling of base-sensitive scaffolds. The high basicity stems from the tradition to trap [18F]fluoride on anion exchange cartridges and elute it afterward with basic anions. This sequence is used to facilitate the transfer of [18F]fluoride from an aqueous to an aprotic organic, polar reaction medium, which is beneficial for SN2 reactions. Furthermore, this sequence also removes cationic radioactive contaminations from cyclotron-irradiated [18O]water from which [18F]fluoride is produced. In this study, we developed an efficient elution procedure resulting in low basicity that permits SN2 18F-labeling of base-sensitive scaffolds. Extensive screening of trapping and elution conditions (>1000 experiments) and studying their influence on the radiochemical yield (RCY) allowed us to identify a suitable procedure for this. Using this procedure, four PET tracers and three synthons could be radiolabeled in substantially higher RCYs (up to 2.5-fold) compared to those of previously published procedures, even from lower precursor amounts. Encouraged by these results, we applied our low-basicity method to the radiolabeling of highly base-sensitive tetrazines, which cannot be labeled using state-of-art direct aliphatic 18F-labeling procedures. Labeling succeeded in RCYs of up to 20%. We believe that our findings facilitate PET tracer development by opening the path toward simple and direct SN2 18F fluorination of base-sensitive substrates.

Mechanisms of arsenic removal from simulated surface water based on As(III) retention on thiol chelating resins

A novel system for arsenic speciation in the aqueous environment has been developed based on the high affinity of As(III) for the sulfhydryl groups present in thiol resins (R-S). The performance of tailor-made cartridges filled with the thiol resin was then compared with a commercial silica-based anion exchange cartridge with a quaternary ammonium group (R-N) typically used for As(V) speciation. Both were able to separate arsenic species efficiently, As(V) and As(III), within a broad pH range using flow rates of up to 5 ml min−1. The R-S resin was shown to be suitable for the inorganic arsenic speciation in aqueous systems containing calcium, magnesium, ferrous and ferric ions. The R-S selectivity for As(III) was affected only at sulfate or phosphate/As mass ratio > 500, in a behavior similar to R-N for As(V). The thiol resin's selectivity for As(III) and its immobilization mechanism were investigated through X-ray Absorption Spectroscopy. At pH 5, each arsenic atom bounds to three sulfur atoms, with an As-S inter-atomic distance of 2.26 ± 0.01 Å, and a coordination number (CN) of 2.8 ± 0.3. The separation of the neutral As(III) species by a thiol resin presents itself as an alternative to the available anion exchange methods. The sorption of As(III) on the thiol resin followed a pseudo-second-order kinetic model and can be described by the Langmuir isotherm.

Fluorimetric determination of the enantiomers of vigabatrin, an antiepileptic drug, by reversed-phase HPLC with a novel diastereomer derivatization reagent.

Herein, determination of an antiepileptic drug, (±)-vigabatrin (VB), was performed by reversed-phase HPLC with fluorimetric detection using a newly designed and synthesized fluorescence derivatization reagent, 2,5-dioxopyrrolidin-1-yl (4-{[(2-nitrophenyl)sulfonyl]oxy}-6-(3-oxomorpholino)quinoline-2-carbonyl)prolinate [Ns-MOK-(R)- or (S)-Pro-OSu]. During the derivatization of VB with Ns-MOK-(R)-Pro-OSu at 60°C, the nosyl (Ns) group, which was introduced to protect a phenolic hydroxy group, was released within 30 min to produce MOK-(R)-Pro-VB, which was detected fluorimetrically at 448 nm with an excitation wavelength of 333 nm. The VB enantiomers were separated on an octadecylsilica (ODS) column with a resolution value of 5.57, because Ns-MOK-(R)-Pro-OSu bears an optically active D-proline structure. A complete separation of MOK-(R)-Pro-(R)- and -(S)-VB enantiomers was achieved on the ODS column within 40 min using stepwise gradient elution, and the detection limits were ~0.80 and 0.37 pmol on the column, respectively. The proposed HPLC with fluorimetric detection method was successfully used for determining VB enantiomers in VB-spiked human serum following solid-phase extraction with an anion-exchange cartridge.

Separation of Long-Lived Radionuclides on QMA Light Anion-Exchange Cartridge in Manufacture of Radiopharmaceutical Preparations Based on 18F

Separation of Long-Lived Radionuclides on QMA Light Anion-Exchange Cartridge in Manufacture of Radiopharmaceutical Preparations Based on 18F

Automated synthesis of [18F]Ga-rhPSMA-7/ -7.3: results, quality control and experience from more than 200 routine productions

IntroductionThe radiohybrid (rh) prostate-specific membrane antigen (PSMA)-targeted ligand [18F]Ga-rhPSMA-7 has previously been clinically assessed and demonstrated promising results for PET-imaging of prostate cancer. The ligand is present as a mixture of four stereoisomers ([18F]Ga-rhPSMA-7.1, − 7.2, − 7.3 and − 7.4) and after a preclinical isomer selection process, [18F]Ga-rhPSMA-7.3 has entered formal clinical trials. Here we report on the establishment of a fully automated production process for large-scale production of [18F]Ga-rhPSMA-7/ -7.3 under GMP conditions (EudraLex).Methods[18F]Fluoride in highly enriched [18O]H2O was retained on a strong anion exchange cartridge, rinsed with anhydrous acetonitrile and subsequently eluted with a solution of [K+ ⊂ 2.2.2]OH− in anhydrous acetonitrile into a reactor containing Ga-rhPSMA ligand and oxalic acid in DMSO. 18F-for-19F isotopic exchange at the Silicon-Fluoride Acceptor (SiFA) was performed at room temperature, followed by dilution with buffer and cartridge-based purification. Optimum process parameters were determined on the laboratory scale and thereafter implemented into an automated synthesis. Data for radiochemical yield (RCY), purity and quality control were analyzed for 243 clinical productions (160 for [18F]Ga-rhPSMA-7; 83 for [18F]Ga-rhPSMA-7.3).ResultsThe automated production of [18F]Ga-rhPSMA-7 and the single isomer [18F]Ga-rhPSMA-7.3 is completed in approx. 16 min with an average RCY of 49.2 ± 8.6% and an excellent reliability of 98.8%. Based on the different starting activities (range: 31–130 GBq, 89 ± 14 GBq) an average molar activity of 291 ± 62 GBq/μmol (range: 50–450 GBq/μmol) was reached for labeling of 150 nmol (231 μg) precursor. Radiochemical purity, as measured by radio-high performance liquid chromatography and radio-thin layer chromatography, was 99.9 ± 0.2% and 97.8 ± 1.0%, respectively.ConclusionThis investigation demonstrates that 18F-for-19F isotopic exchange is well suited for the fast, efficient and reliable automated routine production of 18F-labeled PSMA-targeted ligands. Due to its simplicity, speed and robustness the development of further SiFA-based radiopharmaceuticals is highly promising and can be of far-reaching importance for future theranostic concepts.

Development and application of analytical procedures for the GC–MS/MS analysis of the sulfates metabolites of anabolic androgenic steroids: The pivotal role of chemical hydrolysis

In this work, we present a gas-chromatography tandem mass spectrometry (GC–MS/MS) method for the identification of the sulfo-conjugate metabolites of pseudo-endogenous steroids (endogenous steroids when administered exogenously). We have preliminarily evaluated the performances of different preparations of sulfatases from Pseudomonas aeruginosa and Helix pomatia, characterized by various origins and catalytic activities, and compared the efficacy of the enzymatic hydrolysis with chemical hydrolysis, performed with a mixture of ethyl acetate, methanol, and sulphuric acid. A procedure for the selective isolation of steroid conjugates from the urine matrix has been designed and optimized, based on the “sequential” extraction of the glucuro-conjugated and of the sulfo-conjugated fractions, performed by two different direct methods, i.e. by ion paired extraction or solid-phase extraction. More specifically, the former method is based on the use of N,N-dimethylephedrinium bromide as the ion paired extraction reagent, while the latter on the use of WAX® (weak anion exchange) cartridges. The performance of the newly developed procedure has been assessed by the analysis of real urine excretion samples collected after the oral intake of a single dose of dehydroepiandrosterone (DHEA) or androstenedione (AED), measuring the concentration of epiandrosterone (EpiA) sulfate.Our results have shown the following: (i) although the yields of chemical hydrolysis and enzymatic hydrolysis are in some cases quite similar, the former is generally preferable since it results in the quantitative cleavage of sulfate moiety; (ii) ion paired extraction has been selected as the most reliable method for direct isolation of sulfate steroids from urine matrices; (iii) EpiA sulfate allows to prolong the detectability of DHEA and AED when compared to routinely used steroidal target compounds.

Tetrabutylammonium tosylate as inert phase-transfer catalyst: The key to high efficiency SN2 radiofluorinations

Here we describe use of the tetrabutylammonium p-toluenesulfonate (TBAOTs) as an inert phase transfer catalyst allowing high efficient aliphatic radiofluorination of labeling precursors for the preparation of common radiotracers using only 0.2–1.2 mg of the substrates. With operational convenience (no need for azeotropic drying) and compatibility with the common types of strong anion-exchange cartridges (QMA), this method has a high potential for routine application in various automated synthesizers and offers significant costs reductions due to less precursors used.

A non-anhydrous, minimally basic protocol for the simplification of nucleophilic 18F-fluorination chemistry

Fluorine-18 radiolabeling typically includes several conserved steps including elution of the [18F]fluoride from an anion exchange cartridge with a basic solution of K2CO3 or KHCO3 and Kryptofix 2.2.2. in mixture of acetonitrile and water followed by rigorous azeotropic drying to remove the water. In this work we describe an alternative “non-anhydrous, minimally basic” (“NAMB”) technique that simplifies the process and avoids the basic conditions that can sometimes limit the scope and efficiency of [18F]fluoride incorporation chemistry. In this approach, [18F]F− is eluted from small (10–12 mg) anion-exchange cartridges with solutions of tetraethylammonium bicarbonate, perchlorate or tosylate in polar aprotic solvents containing 10–50% water. After dilution with additional aprotic solvent, these solutions are used directly in nucleophilic aromatic and aliphatic 18F-fluorination reactions, obviating the need for azeotropic drying. Perchlorate and tosylate are minimally basic anions that are nevertheless suitable for removal of [18F]F- from the anion-exchange cartridge. As proof-of-principle, “NAMB” chemistry was utilized for the synthesis of the dopamine D2/D3 antagonist [18F]fallypride.

Permethylation and Microfractionation of Sulfated Glycans for MS Analysis.

Sulfated glycans are barely detectable in routine mass spectrometry (MS)-based glycomic analysis due to ion suppression by the significantly more abundant neutral glycans in the positive ion mode, and sialylated non-sulfated glycans in the negative ion mode, respectively. Nevertheless, the negative charge imparted by sulfate can be advantageous for selective detection in the negative ion mode if the sialic acids can first be neutralized. This is most conveniently achieved by a concerted sample preparation workflow in which permethylation is followed by solid phase fractionation to isolate the sulfated glycans prior to MS analysis. Importantly, we demonstrated that conventional NaOH/DMSO slurry permethylation method can retain the sulfates. Instead of extracting permethylated glycans into chloroform for sample clean-up, reverse phase C18 cartridge coupled with self-packed amine-tip or mixed mode weak anion exchange cartridge can be utilized to obtain in good yield the non-sulfated, mono-sulfated, and multiply sulfated permethylated glycans in separate fractions for sulfoglycomic analysis.

LC-ESI-MS/MS assay development and validation of a novel antidiabetic peptide PSTi8 in mice plasma using SPE: An application to pharmacokinetics

PSTi8 is a 21 amino acid pancreastatin inhibitory peptide that demonstrated potent antidiabetic activity in insulin resistant rodent models. The goal of the current work is to establish and validate the LC–ESI–MS/MS bioanalytical assay of PSTi8 in mice plasma in order to unveil its pharmacokinetic (PK) behaviour for the first time. The MS detection of PSTi8 and diprotin A (internal standard, IS) was conducted with Q1/Q3 SRM transitions at 607.80 ([M+4 H]4+)/771.20 and 342.20/229.10, respectively using positive ESI. Phenomenex Aqua 5μ 125A (250 × 4.6 mm) column was utilized to separate PSTi8 and IS with a mobile phase consists of MeOH-0.1 % formic acid (1:1, v/v) using 0.4 mL/min flow rate. SPE using medium anion exchange cartridge (Oasis MAX) was used for the extraction of analyte and IS from the mice plasma and the extraction recovery was found to be >55 %. PSTi8 displayed good linearity across the 5−1000 ng/mL concentrations range. The intra- and inter- day accuracy was observed between 99.44–110.20 % and 99.66–110.93 %, respectively. The intra- and inter- day precision was observed between 2.61–4.03 % and 2.90–7.16 %, respectively. The intra-day and inter-day accuracy and precision data was within the 100 ± 15 % nominal values recommended by the United States Food and Drug Administration bioanalytical guidance. The LC–MS/MS assay was validated effectively to investigate the PSTi8 plasma concentrations following intravenous and intraperitoneal PK studies in mice. The absolute bioavailability of PSTi8 was 52.74 ± 13.50 %.

Analysis of folic acid in white rice by ultra-fast liquid chromatography

The method of analysis was standardized, and the folic acid content was determined in samples of fortified white rice (Z, G and D) and unfortified (E and O). The analysis was performed in triplicate in samples of 2.0000 g, hydrolysis was performed with phosphate buffer pH 8.82 for one hour and then lowered to pH 7.00 for enzymatic treatment with takadiastase at 65°C. The extracts were filtered by gravity, purified with nylon syringe filters and ion exchange cartridges (solid phase extraction using strong anion exchange cartridges). The concentration in mg folic acid/kg of rice, in each extract was determined by ultrafast liquid chromatography, with average values for Lot1 of the fortified rice samples, of 44.03, 51.95, 38.08, and unfortified samples of 31.51 and 21.94, and with respect to Lot2 of 41.26, 41.27, 34.54 for fortified ones and 24.92 and 20.94 for non-fortified ones, respectively. The concentration of folic acid obtained by filtration through syringe filters was higher than in the extracts purified by solid phase extraction using strong anion exchange cartridges, evidencing loss of the analyte. The recovery of folic acid in the samples doped and purified by syringe filters was around 65.00%, while by solid phase extraction using strong anion exchange cartridges 43.00%. There is evidence of variation in the folic acid content between different batches of rice of the same brand.

Simultaneous determination of organophosphorus nerve agent markers in urine by IC-MS/MS using anion-exchange solid-phase extraction

In this study a comprehensive approach for determination of low molecular organophosphorus nerve agent markers – highly polar alkylphosphonic acids and much less polar alkyl methylphosphonic acids is presented. Accurate, sensitive and simultaneous determination of the nerve agent markers in human urine was performed by ion chromatography and tandem mass spectrometry using deuterated internal standards. Analysis of the urine extracts was conducted on an anion-exchanger based on poly(styrene-co-divinylbenzene) substrate with a high degree of crosslinking and a covalently-bonded branched functional layer. The use of this type of column allowed achieving high values of retention factors for alkylphosphonic acids and alkyl methylphosphonic acids due to combination of anion-exchange and hydrophobic interactions between the analytes and the stationary phase of the column. Prior to the analysis, the urine samples were purified using anion-exchange cartridges for solid-phase extraction, and high recovery values were achieved for each analyte. The developed IC-MS/MS technique was validated for linearity, limit of detection, limit of quantification, precision and accuracy using two LC-MS/MS instruments. The proposed approach was successfully tested on the urine samples, provided by the Organisation for the Prohibition of Chemical Weapons in the frame of the 4th Biomedical Proficiency Test.

Fast and efficient copper-mediated 18F-fluorination of arylstannanes, aryl boronic acids, and aryl boronic esters without azeotropic drying

BackgroundCopper-mediated radiofluorination is a straightforward method to produce a variety of [18F]fluoroarenes and [18F]fluoroheteroarenes. To minimize the number of steps in the production of 18F-labelled radiopharmaceuticals, we have developed a short and efficient azeotropic drying-free 18F-labelling method using copper-mediated fluorination. Our goal was to improve the copper-mediated method to achieve wide substrate scope with good radiochemical yields with short synthesis time.ResultsSolid phase extraction with Cu (OTf)2 in dimethylacetamide is a suitable activation method for [18F]fluoride. Elution efficiency with Cu (OTf)2 is up to 79% and radiochemical yield (RCY) of a variety of model molecules in the crude reaction mixture has reached over 90%. Clinically relevant molecules, norepinephrine transporter tracer [18F]NS12137 and monoamine transporter tracer [18F]CFT were produced with 16.5% RCY in 98 min and 5.3% RCY in 64 min, respectively.ConclusionsCu (OTf)2 is a suitable elution agent for releasing [18F]fluoride from an anion exchange cartridge. The method is fast and efficient and the Cu-complex is customizable after the release of [18F]fluoride. Alterations in the [18F]fluoride elution techniques did not have a negative effect on the subsequent labelling reactions. We anticipate this improved [18F]fluoride elution technique to supplant the traditional azeotropic drying of [18F]fluoride in the long run and to concurrently enable the variations of the copper-complex.

A simple decontamination procedure for unintended iodide impurity during [11C]methionine production

A solid-phase extraction cartridge method is a widely used carbon-11 labeling method for obtaining [11C]methionine. Although the process is convenient and efficient, unintended impurity sometimes observed in the final product owing to contamination by volatile iodide generated during [11C]CH3I production. Herein, we suggest a simple method to eliminate impurities contained in [11C]methionine solution using an anion-exchange resin cartridge.

Determination of N-Carbamoylglutamate in Rumen Fluid

N-carbamoylglutamate (NCG) is a feed additives obtained synthetically from sodium glutamate,which is a structural analogue of N-acetylglutamate. Current study is aimed at developing ion chromatographic method for the determination of NCG in rumen fluid. Successful determination was performed on cation-exchange column and non-suppressed conductivity detection with total rune time of 11 minutes. Simple one-step cleanup using anion exchange cartridge was used to remove interfering compounds. Method was applied to determine NCG in rumen fluid, which was obtained from three rumen fistulated dairy cows. Incubated NCG sample in rumen fluid was assessed at various time intervals (0, 2, 4, 6, 12 and 24 h at 39 oC). Results showed that NCG was disappeared at the rate of 7.8, 12.8, 13.3, 14.2, and 17.8 % at 2, 4, 6, 12 and 24 h, respectively. It is concluded from the results that the procedure is quick and uncomplicated. NCG can be detected in rumen fluid without lengthy separation using cation-exchange chromatography. This technique can be applied for determination of NCG in rumen fluid as well as for practical use in animals feed.

Field-amplified sample injection and sweeping micellar electrokinetic chromatography in analysis of glyphosate and aminomethylphosphonic acid in wheat

Glyphosate, a widely used herbicide, has been classified as probably carcinogenic to humans by the International Agency for Research on Cancer (IARC). In the present study a method based on Field-Amplified Sample Injection and Sweeping Micellar Electrokinetic Chromatography (FASI sweep-MEKC) has been developed and validated for determination of glyphosate and its microbial metabolite aminomethylphosphonic acid (AMPA) in wheat flour. The method involved a preliminary solid phase extraction for cleanup of the aqueous extracts from wheat flour, based sequentially on C18 and strong anion exchange cartridges, followed by derivatization using 9-fluorenylmethylchloroformate. Optimization of sample cleanup and derivatization procedure was carried out by a HPLC-UV method, whereas FASI sweep-MEKC was applied for achieving the sensitivity necessary for analysis of real samples. To this regard, optimum conditions involved the use of an extended path fused-silica capillary (80 cm total length, 50 μm, i.d.) filled with a high concentration buffer (sodium phosphate 100 mM, pH 2.2). Electrokinetic sampling was carried out at −10 kV with injection time of 700 s and the separation of the loaded analytes was performed under MEKC conditions using sodium phosphate buffer 50 mM at pH 2.2, supplemented with sodium dodecyl sulfate, 100 mM. The method was validated for linearity, precision, accuracy and sensitivity, showing that using conventional UV detection (210 nm) the achieved limit of quantitation (LOQ) values for both the analytes were widely lower than those set by Authorities. In particular, LOQ for glyphosate and AMPA were found to be 5 and 2.5 ng/mL, respectively, corresponding to 0.1 and 0.05 mg/kg, in wheat flour. The method, applied to commercially available real samples (wheat flour from different manufacturers) and to an experimental sample obtained by cv. Svevo wheat, can be considered as a convenient alternative to the existing approaches in analysis of complex matrices.

A single analytical method for the determination of 53 legacy and emerging per- and polyfluoroalkyl substances (PFAS) in aqueous matrices.

A quantitative method for the determination of per- and polyfluoroalkyl substances (PFAS) using liquid chromatography (LC) tandem mass spectrometry (MS/MS) was developed and applied to aqueous wastewater, surface water, and drinking water samples. Fifty-three PFAS from 14 compound classes (including many contaminants of emerging concern) were measured using a single analytical method. After solid-phase extraction using weak anion exchange cartridges, method detection limits in water ranged from 0.28 to 18ng/L and method quantitation limits ranged from 0.35 to 26ng/L. Method accuracy ranged from 70 to 127% for 49 of the 53 extracted PFAS, with the remaining four between 66 and 138%. Method precision ranged from 2 to 28% RSD, with 49 out of the 53 PFAS being below < 20%. In addition to quantifying > 50 PFAS, many of which are currently unregulated in the environment and not included in typical analytical lists, this method has efficiency advantages over other similar methods as it utilizes a single chromatographic separation with a shorter runtime (14min), while maintaining method accuracy and stability and the separation of branched and linear PFAS isomers. The method was applied to wastewater influent and effluent; surface water from a river, wetland, and lake; and drinking water samples to survey PFAS contamination in Australian aqueous matrices. The compound classes FTCAs, FOSAAs, PFPAs, and diPAPs were detected for the first time in Australian WWTPs and the method was used to quantify PFAS concentrations from 0.60 to 193ng/L. The range of compound classes detected and different PFAS signatures between sample locations demonstrate the need for expanded quantitation lists when investigating PFAS, especially newer classes in aqueous environmental samples. Graphical abstract.