Mixed-mode Polymeric Sorbent Research Articles

Simultaneous determination of four Sudan dyes in rat blood by UFLC–MS/MS and its application to a pharmacokinetic study in rats

A rapid and sensitive method based on ultrafast liquid chromatography–tandem mass spectrometry was developed and validated for simultaneous determination of Sudan I, Sudan II, Sudan III, and Sudan IV levels in rat whole blood. Cleanert C18 mixed-mode polymeric sorbent was used for effective solid-phase extraction cleanup. Separation was carried out on a reversed-phase C18 column (100mm×2.1mm, 1.8μm) using 0.1% (v/v) formic acid in water/0.1% (v/v) formic acid in acetonitrile as the mobile phase in gradient elution. Quantification was performed by an electrospray ionization source in the positive multiple reaction monitoring mode using D5-Sudan I as the internal standard. Calibration curves showed good linearity between 0.2 and 20.0μg/L, with correlation coefficients higher than 0.9990. The average recovery rates were between 93.05% and 114.98%. The intra- and inter-day relative standard deviations were within 6.2%. The lower limit of quantification was 0.2μg/L. All the analytes were found to be stable in a series of stability studies. The proposed method was successfully applied to a pharmacokinetic study of four Sudan dyes after oral administration to rats.

Development of an analytical strategy based on LC–MS/MS for the measurement of different classes of pesticides and theirs metabolites in meconium: Application and characterisation of foetal exposure in France

It is important to evaluate the impact of pesticides on human health because exposure to these compounds has been linked to harmful effects in many research studies. This exposure may be particularly harmful during the early stages of development (e.g. the prenatal period). The aim of the present study was to develop an analytical strategy for quantifying a number of pesticides and their metabolites in meconium (the neonate׳s first faeces), in order to characterize the extent of foetal exposure. The meconium sample was dried and grinded in order to homogenize the sample, prior to solid–liquid extraction and a purification by solid-phase extraction using a weak anion mixed-mode polymeric sorbent. Analyte separation and quantification was performed by liquid chromatography coupled to electrospray-triple quadrupole mass spectrometry. Five pesticide families (carbamates, organophosphates, pyrethroids, phenylureas and phenoxy herbicides) and their metabolites could be quantified in meconium with limits of quantification ranging between 0.2ng/g and 200ng/g. This method was applied to a set of 171 meconium samples collected in the Picardie region of northern France. The highest prevalence was observed for metabolites of organophosphates and carbamates (57.9% and 22.8%, respectively). The parent pesticides were rarely present and were only found at very low concentrations, except for the pyrethroids cyfluthrin and cypermethrin, which were found in 7.6% of meconium samples at concentrations of between 43.8 and 480ng/g. The most frequently detected contaminant was the organophosphate metabolite dimethyl thiophosphate detected in 49.1% of the samples and quantified with a median concentration of 344ng/g. These data evidence significant foetal exposure to organophosphate pesticides, pyrethroids and carbamates.

How to address the sample preparation of hydrophilic compounds: Determination of entecavir in plasma and plasma ultrafiltrate with novel extraction sorbents

Two fast, simple, selective and economical sample preparation methods for the determination of entecavir in biological materials available at low amounts are reported. The choice of optimal extraction techniques was performed with regard to analyte hydrophilicity, sample volumes, selectivity, method recovery and rapidity. The compatibility of the eluate with the hydrophilic interaction chromatography (HILIC) mobile phase was crucial to allow the elimination of the evaporation and reconstitution steps and to obtain acceptable peak shapes.Different types of sorbents were employed for the extraction of two biological materials (plasma and plasma ultrafiltrate). The mixed-mode polymeric sorbent MCX was chosen as a suitable one for the solid phase extraction (SPE) of plasma samples. The analytes were eluted with 1ml of the mixture of 5 % ammonium hydroxide in ACN:water (95:5). Protein precipitation (PP) with 1ml of ACN was used to remove proteins from 500μl of plasma sample prior to SPE extraction. The microextraction by packed sorbent (MEPS) was employed for the cleaning up of plasma ultrafiltrate samples due to very small volumes available for the analysis. MEPS implemented a novel sorbent based on porous graphitic carbon, semi-automatic analytical syringe and a small volume of sample (50μl). The elution step was performed using 100μl of the mixture of 5mM ammonium acetate pH 4.0:ACN (25:75). The MEPS eluate was fully compatible with HILIC mobile phase subsequently used for the analysis of entecavir, unlike SPE eluate, which had to be evaporated and reconstituted in mobile phase.Both analytical methods were validated and demonstrated good linearity in a range 1–100ng/ml (r2>0.9992) for plasma samples and in a range 0.5–100ng/ml (0.9991) for the plasma ultrafiltrate samples. Intra-day accuracy expressed as recovery was within the range from 80–98% for the plasma samples and 97–106% for the plasma ultrafiltrate samples. Inter-day accuracy ranged within 81–106% for the plasma and 95–101% for the plasma ultrafiltrate samples. The intra-day precision expressed as the % of RSD was lower than 4% for both matrices and inter-day precision was lower than 7% for plasma and lower than 17% for plasma ultrafiltrate. Method sensitivity reached LLOQ of 1ng/ml in plasma and 0.5ng/ml in plasma ultrafiltrate samples. The method was applied for the determination of concentration–time profiles of entecavir in plasma of the perfusate for rat kidney perfusion and for the measurement of concentration of entecavir in plasma ultrafiltrate samples. The results should be helpful in the evaluation of excretion mechanism of entecavir.

The UHPLC-DAD fingerprinting method for analysis of extracellular metabolites of fungi of the genus Geosmithia (Acomycota: Hypocreales)

A new simple ultra-high-performance liquid chromatography method with diode array detection (UHPLC-DAD) was developed for chemical fingerprinting analysis of extracellular metabolites in fermentation broth of Geosmithia spp. The SPE method employing Oasis MCX strong cation-exchange mixed-mode polymeric sorbent was chosen for extraction of the metabolites. The analyses were performed on an Acquity UPLC BEH C18 column (100 × 2.1 mm i.d.; particle size, 1.7 μm; Waters) using a gradient elution program with an aqueous solution of trifluoroacetic acid and acetonitrile as the mobile phase. The applicability of the method was proved by analysis of 38 strains produced by different species and isolated from different sources (hosts). The results revealed the correlation of obtained UHPLC-DAD fingerprints with taxonomical identity.

Abstract P5-11-09: A Validated Analytical Method for Monitoring the Plasma Levels of Tamoxifen, Anastrozole and Letrozole in Patients Undergoing Endocrine Therapy

Abstract Background: Clinical data have repeatedly shown that tamoxifen as well as anastrazole and letrozole significantly increase the overall survival among breast cancer patients. However, in several cases the use of these drugs is limited by side effects, whose appearance are described to impair the adherence of a patient to endocrine treatment. Frequently, adherence is rated based on patient self-reports. One competent approach to obtain impartial information about patient adherence and its clinical relevance is based on the determination of plasma drug concentrations. The individual steady state plasma level represents an objective measure that may serve as an important comparator to check the patient-reported adherence status in clinical studies. In addition, it may also reveal useful information for the treating physician regarding concentration dependent side effects or therapeutic failure. We have developed and validated a liquid chromatography-tandem mass spectrometry (LC/MS/MS) method for the simultaneous analysis of tamoxifen, anastrazole and letrozole in human plasma. The method was applied in the PRO-BETh study to monitor 320 breast cancer patients undergoing endocrine therapy. Material and methods: Blood plasma samples were collected from 320 patients undergoing endocrine breast cancer therapy and stored at -20° C. To prepare a sample for LC/MS/MS analysis, 1 ml plasma was treated with a solid phase extraction procedure using a cation mixed-mode polymeric sorbent phase (Strata-X-C cartridges, Phenomenex, CA). Chromatographic separation was accomplished on a reversed-phase column (200 mm x 0.5 mm, Eurosphere-C18, 5 μm, Knauer, Berlin) by using a gradient of acetone in an aqueous hexafluorobutyric acid solution. Mass spectrometric detection was performed on a quadrupole-quadrupole-linear ion trap instrument (Q Trap 3200, Applied Biosystems, Foster City, CA). Results: We have developed a fully validated method for the simultaneous quantitative analysis of tamoxifen, anastrozole and letrozole in human plasma. Validation was accomplished for a concentration range of 25-500 ng/ml for tamoxifen, 10-200 ng/ml for endoxifen, 5-200 ng/ml for anastrozol and 10-300 ng/ml for letrozole. The applicability of the method was demonstrated in the context of the PRO-BETh study, by analyzing plasma samples of 320 patients undergoing endocrine breast cancer therapy. The observed plasma levels showed a high inter-patient variability with measured values between 26-307 ng/ml (mean 125 ng/ml) regarding tamoxifen, 17-301 ng/ml (mean 107 ng/ml) regarding letrozole and 6-102 ng/ml (mean 37 ng/ml) regarding anastrozole. Eight samples did not contain a quantifiable amount of drug, indicating longer abstinence of the corresponding patients regarding endocrine therapy. Conclusions: The developed method represents a reliable and convenient tool for the quantitative analysis of tamoxifen, anastrozol and letrozole in human plasma. The method is dedicated to drug monitoring which is an important part of adherence rating. As exemplified in the context of the PRO-BETh study, the measured steady state plasma levels represent objective measures that serve as important comparators to check the patient-reported adherence status. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-11-09.

Weak anion-exchange hypercrosslinked sorbent in on-line solid-phase extraction–liquid chromatography coupling to achieve automated determination with an effective clean-up

A mixed-mode polymeric sorbent was on-line coupled to liquid chromatography (LC) for the first time and applied to the selective solid-phase extract a group of pharmaceuticals in complex environmental water samples. The mixed-mode polymeric sorbent is a high-specific surface area hypercrosslinked polymer resin (HXLPP) in the form of monodisperse microspheres further modified with 1,2-ethylenediamine (EDA) moieties. These properties allow its application as a weak anion-exchange (WAX) sorbent in the on-line solid-phase extraction (SPE) coupling. The on-line SPE-LC method developed using the HXLPP-WAX sorbent was successfully applied to percolate a large volume of ultrapure (500 ml), river (250 ml) and effluent sewage (100 ml) water samples. In all the cases, the HXLPP-WAX resin provided near total recoveries of the most acidic compounds studied and clean chromatograms. This is because the ion-exchange interactions enable a washing step to be added to the SPE protocol that removes the compounds with weak acidic, neutral and basic properties from the sample matrix.

Multiresidue methods for the analysis of pharmaceuticals, personal care products and illicit drugs in surface water and wastewater by solid-phase extraction and ultra performance liquid chromatography–electrospray tandem mass spectrometry

The main aim of the presented research is to introduce a new technique, ultra performance liquid chromatography-positive/negative electrospray tandem mass spectrometry (UPLC-ESI/MS/MS), for the development of new simultaneous multiresidue methods (over 50 compounds). These methods were used for the determination of multiple classes of pharmaceuticals (acidic, basic and neutral compounds: analgesic/anti-inflammatory drugs, antibiotics, antiepileptics, beta-adrenoceptor blocking drugs, lipid regulating agents, etc.), personal care products (sunscreen agents, preservatives, disinfectant/antiseptics) and illicit drugs (amphetamine, cocaine and benzoylecgonine) in surface water and wastewater. The usage of the novel UPLC system with a 1.7 microm particle-packed column allowed for good resolution of analytes with the utilisation of low mobile phase flow rates (0.05-0.07 mL min(-1)) and short retention times (method times of up to 25 min), delivering a fast and cost-effective method. SPE with the usage of Oasis MCX strong cation-exchange mixed-mode polymeric sorbent was chosen for sample clean-up and concentration. The influence of mobile phase composition, matrix-assisted ion suppression in ESI-MS and SPE recovery on the sensitivity of the method was extensively studied. The method limits of quantification were at low nanogram per litre levels and ranged from tenths of ng L(-1) to tens of ng L(-1) in surface water and from single ng L(-1) to a few hundreds of ng L(-1) in the case of wastewater. The instrumental and method intraday and interday repeatabilities were on average less than 5%. The method was successfully applied for the determination of pharmaceuticals in the River Taff (South Wales) and a wastewater treatment plant (WWTP Cilfynydd). Several pharmaceuticals and personal care products were determined in river water at levels ranging from single ng L(-1) to single microg L(-1).

The effect of signal suppression and mobile phase composition on the simultaneous analysis of multiple classes of acidic/neutral pharmaceuticals and personal care products in surface water by solid-phase extraction and ultra performance liquid chromatography–negative electrospray tandem mass spectrometry

A new multi-residue method for the determination of 25 acidic/neutral pharmaceuticals (antibiotics, anti-inflammatory/analgesics, lipid regulating agents, diuretics, triazides, H2-receptor antagonists, cardiac glicozides and angiotensin II antagonists) and personal care products (sunscreen agents and preservatives) in surface water with the usage of a new technique: ultra performance liquid chromatography–negative electrospray tandem mass spectrometry (UPLC–MS/MS) was developed and validated. The novel UPLC system with 1.7 μm particle-packed column allowed for good resolution of analytes with the application of low mobile phase flow rates (0.05 mL min −1) and short retention times (from 4.7 min to 13.3 min) delivering a fast and cost-effective multi-residue method. SPE with the usage of Oasis MCX strong cation-exchange mixed-mode polymeric sorbent was chosen for sample clean-up and concentration. The influence of mobile-phase composition, matrix assisted ion suppression and SPE recovery on the sensitivity of the method was identified and quantified. The instrumental limits of quantification varied from 0.2 μg L −1 to 30 μg L −1. The method limits of quantification were at low nanogram per litre levels and ranged from 0.3 ng L −1 to 30 ng L −1. The instrumental and method intra-day and inter-day repeatabilities were on average less than 5%. The method was successfully applied for the determination of PPCPs in River Taff. Thirteen compounds were determined in river water at levels ranging from a single to a few hundred nanograms per litre. Among them were ten pharmaceuticals (aspirin, salicylic acid, ketoprofen, naproxen, diclofenac, ibuprofen, mefenamic acid, furosemide, sulfasalazine and valsartan) and three personal care products (methyl- and ethylparaben and 4-benzophenone).

Multi-residue method for the determination of basic/neutral pharmaceuticals and illicit drugs in surface water by solid-phase extraction and ultra performance liquid chromatography–positive electrospray ionisation tandem mass spectrometry

The paper presents the development and validation of a new multi-residue method for the determination of 28 basic/neutral pharmaceuticals (antiepileptics, antibacterial drugs, β-blockers, analgesics, lipid-regulating agents, bronchodilators, histamine-2-blockers, anti-inflammatory agents, calcium channel blockers, angiotensin-II antagonists and antidepressants) and illicit drugs in surface water with the usage of a new technique: ultra performance liquid chromatography–positive electrospray tandem mass spectrometry (UPLC–MS/MS). The usage of the novel UPLC system with 1.7 μm particle size and 1 mm internal diameter column allowed for low mobile phase flow rates (0.07 mL min −1) and short retention times (from 1.3 to 15.5 min) for all compounds analysed. As a result, a fast and cost-effective method was developed. SPE with the usage of Oasis MCX strong cation-exchange mixed-mode polymeric sorbent was chosen for pharmaceuticals extraction from environmental samples. The influence of matrix-assisted ion suppression and low SPE recovery on the sensitivity of the method was studied. The instrumental limits of quantification varied from 0.2 to 10 μg L −1. The method limits of quantification were at low nanogram per litre levels and ranged from 0.3 to 50 ng L −1. The instrumental and method intra- and inter-day repeatabilities were on average less than 10%. The method was applied for the determination of pharmaceuticals in Rivers Taff (UK) and Warta (Poland). Fifteen compounds were determined in river water at levels ranging from single nanograms to single micrograms per litre.

Solid–liquid extraction and cation-exchange solid-phase extraction using a mixed-mode polymeric sorbent of Datura and related alkaloids

Tropane alkaloids solid–liquid extraction methods were developed and comprised ambient pressure ones: extraction with hot solvent, extraction at room temperature, on ultrasonic bath as well as pressurised liquid extraction (PLE) techniques. The highest yields of l-hyoscyamine in methanol PLE method (3 × 5 min, 110 °C) and scopolamine extracted with 1% tartaric acid in methanol (15 min, 90 °C) were determined. A mixed-mode reversed-phase cation-exchange solid-phase extraction (SPE) procedure was optimised for simultaneous recoveries of l-hyoscyamine, scopolamine, scopolamine– N-oxide from plant extracts as well as quaternary alkaloid representative: scopolamine– N-methyl bromide. First three alkaloids were efficiently eluted (recoveries 80–100%) from an Oasis MCX cartridge with methanol–10% ammonia (3:1, v/v) solution, whereas for the quaternary salt tetrahydrofuran–methanol–25% ammonia (6:1:3, v/v) was used with recoveries 52–6%. HPTLC-densitometric assay on silica gel plates was elaborated at 205 nm without derivatization and included: single development (over a distance 9.5 cm) with acetone–methanol–water–25% ammonia (85:5:5:8, v/v) mobile phase for l-hyoscyamine and scopolamine separation, whereas for scopolamine–N-oxide and scopolamine– N-methyl bromide a second development (to a distance 5.5 cm) with acetonitrile–methanol–85% formic acid (120:5:5, v/v) was applied. Newly elaborated RP-HPLC-diode array detection method was performed on Waters XTerra RP-18 column with gradient of acetonitrile in 15 mM ammonia solution and alkaloids were baseline separated within 20 min. Both chromatographic methods were validated and their quantitative results were compared. Good correlation between HPLC and HPTLC quantitative results was measured (correlation coefficients of mean values were 0.92086 and 0.99995 for l-hyoscyamine and scopolamine, respectively). In the RP-HPLC method, which was from 1.5- up to 7-fold more sensitive than HPTLC, limits of detection (LOD) and limits of quantitation (LOQ, in bracket) were (in ng/μl) as follows: 0.25 (0.82) for l-hyoscyamine, 0.29 (0.97) for scopolamine, 0.13 (0.45) for scopolamine– N-oxide and 0.58 (1.91) for scopolamine– N-methyl bromide. By the use of the optimised chromatographic methods, 14 various samples from the leaves and fruits of Datura sp. were screened for l-hyoscyamine and scopolamine contents and the most promising samples were established.