Simple Solid-phase Extraction Method Research Articles

Selective cationic covalent organic framework for high throughput rapid extraction of novel polyfluoroalkyl substances.

Novel per- and polyfluoroalkyl substances (PFASs) raise global concerns due to their toxic effects on environment and human health. However, researches on analytical methods of novel PFASs are lacking. Here, a kind of selective cationic covalent organic framework (iCOF) was designed and loaded on the surface of cotton as an adsorbent. Then, a simple solid-phase extraction (SPE) method based on the cotton@iCOF was developed for high throughput rapid extraction of six novel PFASs in water samples, coupled with ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) determination. Several important SPE parameters, such as the amount of iCOF, sample pH, desorption conditions and salinity were systematically investigated. Under optimal conditions, the limits of detection and quantification of this SPE-UHPLC-MS/MS method were as low as 0.08-2.14ng/L and 0.28-7.15ng/L, respectively. The recoveries were 77.9-117.6% for the tap water and surface water, and F-53 B in surface water were detected. Notably, this SPE process was rapid (1h for 500mL water sample) compared with commercial SPE (normal 2-3h), owing to little resistance of cotton@iCOF and omission of nitrogen blowing process, and high throughput with 12 samples concurrently extracted. Additionally, various characterization means and density functional theory (DFT) calculations showed that ion-exchange effect, hydrophobic interaction, hydrogen bonding and ordered channel structure synergistically contributed to the PFASs adsorption on cotton@iCOF. The cotton@iCOF-based SPE method with simplicity, rapidity, selectivity and efficiency provided new research ideas for the analysis and control of ionic emerging pollutants in water.

Solid-phase extraction of nerve agent degradation products using poly[(2-(methacryloyloxy)ethyl)trimethylammonium chloride] thin films

In this study, a simple solid-phase extraction (SPE) technique was developed to extract organophosphonic acids as degradation products of nerve agents from aqueous samples for identification by instrumental analyses such as FT-IR, TOF-SIMs and GC-MS. To selectively extract the organophosphonic acids, we synthesized an anion exchange polymer film on a gold plate using surface-initiated controlled radical polymerization with 2-[(methacryloyloxy)ethyl]trimethylammonium chloride. Extraction of the organophosphonic acids onto the plates was successfully confirmed by polarized angle fourier transformation-infra red (FT-IR) spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry analyses. The limit of detection of the developed SPE method satisfied the detection limit of Chemical Warfare Agents verification criteria by FT-IR analysis. After optimization, the detection limit values were found to be between 0.1 and 0.4 µg mL−1, and the recovery ranged from 50% to 110% in aqueous solution containing various interference. In addition, the SPE process was successfully applied to the detection of pinacolyl methylphosphonic acid, the degradation product of soman, in the 35th Organization for Prohibition of Chemical Weapons proficiency test sample.

A simple solid-phase extraction method for the analysis of red cell phospholipids by liquid chromatography- tandem mass spectrometry.

There has been increasing interest in the analysis of phospholipids in red blood cells as potential long-term biomarkers of different disease states. Here, we describe a simple method for the analysis of two phospholipids: 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanol (PE 16:0/18:1) and 1-Palmitoyl-2-linoleoyl-sn-glycero-3-phosphoethanol (PE 16:/0/18:2) in erythrocytes by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Whole blood samples were removed free of plasma and washed in isotonic saline. Red cells were lysed with ultrapure water. Lysate samples were processed using a hybrid solid-phase extraction (SPE) phospholipid cartridge (1 mL, 30 mg). Both PE 16:0/18:1 and PE 16:0/18:2 and their deuterated internal standards were separated on an ACE C4 (150mm × 2.1mm, 2.7μm particle size) by gradient elution at a flow rate of 0.5 mL per minute using mobile phases consisting of 0.01 mol/L ammonium acetate in: water (A), methanol (B), and isopropanol (C). The phospholipid species were quantified by the following transitions: PE 16:0/18:1: 701.5→281.3 and PE 16:0/18:2: 699.5→279.3. Both PE species displayed linearity ranging from 10 to 500μg/L. The coefficient of variation (CV%) of PE 16:0/18:1 concerning intraday and interday precision was between 1.9%-2.6% and 3.0%-4.3%, respectively. For PE 16:0/18:2, this was between 1.8%-3.4% and 3.7%-4.1%, respectively. Both phospholipid species had accuracy (PE 16:0/18:1: 91%-98% and PE 16:0/18:2: 94%-103%) and extraction recovery (PE 16:0/18:1: 95%-106% and PE 16:0/18:2: 92%-102%) exceeding 90% over the analytical range. The limit of detection was 5μg/L. Here we propose a simple SPE LC-MS/MS method for analyzing phospholipids in erythrocytes, which can be easily adopted.

Development and validation of a simple solid-phase extraction method coupled with liquid chromatography-triple quadrupole tandem mass spectrometry for simultaneous determination of lincomycin, tylosin A and tylosin B in royal jelly.

We have developed an analytical method for the determination of lincomycin, tylosin A and tylosin B residues in royal jelly using liquid chromatography-triple quadrupole tandem mass spectrometry analysis. For extraction and purification, we employed 1% trifluoroacetic acid and 0.1m Na2 EDTA solutions along with an Oasis HLB cartridge. The target antibiotics were well separated in a Kinetex EVO C18 reversed-phase analytical column using a combination of 0.1% formate acid in ultrapure water (A) and acetonitrile (B) as the mobile phase. Good linearity was achieved over the tested concentration range (5-50 μg/kg) in matrix-matched standard calibration. The coefficients of determination (R2 ) were 0.9933, 0.9933 and 0.996, for tylosin A, tylosin B and lincomycin, respectively. Fortified royal jelly spiked with three different concentrations of the tested antibiotics (5, 10 and 20 μg/kg) yielded recoveries in the range 80.94-109.26% with relative standard deviations ≤4%. The proposed method was applied to monitor 11 brand of royal jelly collected from domestic markets and an imported brand from New Zealand; all the samples tested negative for lincomycin, tylosin A and tylosin B residues. In conclusion, 1% trifluoroacetic acid and 0.1m Na2 EDTA aqueous solvents combined with solid-phase extraction could effectively complete the sample preparation process for royal jelly before analysis. The developed approach can be applied for a routine analysis of lincomycin, tylosin A and tylosin B residues in royal jelly.

Citrus reticulata Blanco peels as a source of antioxidant and anti-proliferative phenolic compounds

Citrus reticulata Blanco industrial use worldwide generates millions of tons of by-products, mainly peels, with negative environmental impact. The main purpose of this work was to compare the extraction efficiency of water and 70% ethanol, for recovering C. reticulata peel phenolic compounds. A simple solid phase extraction method was used for obtaining enriched phenolic extracts. There were no significant differences in the extraction efficiency for the two solvents used. The main components were hesperidin, naringin, tangeritin, and rutin, that accounted for nearly 86% of the total phenolics extracted. Solid phase extraction allowed a 4.5-fold enrichment in phenolics and antioxidant activity of the extracts. The anti-proliferative activity of the extracts was found to be dose-dependent but also dependent on the cell line. The solid phase extraction enriched phenolic extracts after 48h exposure presented an IC50 of 174.5±5.8μg/mL (BT-474), 391.9±15μg/mL (Caco-2) and >500.00μg/mL (HepG2). These results show that C. reticulata peels are a cheap and abundant source of antioxidant and potentially bioactive phenolic compounds.

Ultrasensitive determination of pyrroloquinoline quinone in human plasma by HPLC with chemiluminescence detection using the redox cycle of quinone

A fast, accurate, and ultrasensitive high-performance liquid chromatography method with chemiluminescence detection (HPLC-CL) was optimized and validated for the determination of pyrroloquinoline quinone (PQQ) concentration in human plasma following solid-phase extraction (SPE). This method is based on the redox cycle of the reaction between PQQ and dithiothreitol, which generates reactive oxygen species that can be detected using luminol as a CL probe. The isocratic HPLC system comprised an ODS column and 4.0mM tetra-n-butylammonium bromide in Tris-HNO3 buffer (pH 8.8; 50mM)-acetonitrile (7:3, v/v) as mobile phase. A novel, rapid, and simple SPE method was also developed providing excellent %recovery (≥95.2%) for PQQ from human plasma samples. The proposed method was linear over the range of 4.0–400nmol/L plasma of PQQ with a lower detection limit (S/N=3) of 1.08 nmol/L plasma (0.27nM). The method was successfully implemented to determine PQQ concentration in the plasma of healthy individuals after administration of PQQ supplements.

A new separation and preconcentration method for selenium in some foods using modified silica gel with 2,6-diamino-4-phenil-1,3,5-triazine.

A novel and simple solid phase extraction method was improved and recommended for selenium. Silica gel was modified with 2,6-diamino-4-phenil-1,3,5-triazine and characterized by FTIR, SEM and elemental analysis and used adsorbent for column solid phase extraction of selenium ions. The experimental parameters (pH, flow rates, amounts of the modified silica gel, concentration and type of eluent, volume of sample, etc.) on the recoveries of selenium were optimized. Standard reference materials were analyzed for validation of method. The present method was successfully applied to the detection of total selenium in water and microwave digested some food samples with quantitative recoveries (> 95%). The relative standard deviations were<8%. Matrix influences were not observed. The adsorption capacity of modified silica gel was 5.90mgg-1. The LOD was 0.015μgL-1. Enrichment factor was obtained as 50 for the introduced method.

Using activated attapulgite as sorbent for solid-phase extraction of melamine in milk formula samples

In this study, a simple solid-phase extraction (SPE) approach by using activated attapulgite as sorbent was successfully developed for the determination of melamine in milk formula samples. Crucial factors impacting the extraction efficiency, including sample solvent, elution solvent, and sample loading volume, were investigated. Under the optimal extraction conditions, the sample loading volume was up to 200mL and the adsorption capacity of the melamine gave rise to 1154μgg(-1). Excellent linear calibration curves (r (2) > 0.999) were achieved, and then the limit of detection (S/N = 3) and the limit of quantification (S/N = 10) were found to be 0.15 and 0.5ngmL(-1), respectively. The recoveries of the melamine spiked in four milk formula samples at three concentration levels ranged from 83.5 to 111.0% with relative standard deviations (RSDs) less than 10.2%. Furthermore, RSDs of batch to batch (n = 4) of the acidified attapulgite used in this developed method were in the range of 2.3∼7.3%. In comparison to the commercial Oasis MCX, the acidified attapulgite sorbent even outperformed (at least in terms of reproducibility) for melamine analysis in real food samples. Because of its simplicity, the newly developed SPE method based on acidified attapulgite nanoparticles should provide a promising tool for daily monitoring of doped melamine in milk formula or other complex matrices.

Simple Solid-Phase Extraction Method for High Efficiency and Low-Cost Crude Oil Demulsification

A novel and simple method for petroleum emulsion breaking and desalting is described and applied to crude oil. Such complex samples consist of stable water–oil emulsions. The oil phase is comprised of petroleum whereas the aqueous phase is composed of brine, including seawater, with varying salt content. Herein, crude oil dewatering was performed by applying a small aliquot of sample to a supported-liquid extraction cartridge. Multiphasic equilibration allowed the aqueous phase to adsorb onto the surface of porous diatomaceous earth (e.g., Celite). Organic solvents such as n-heptane, methylene chloride, and toluene easily desorbed the remaining oil phase. Potentiometric Karl Fisher titration and conductivity analysis confirmed near exhaustive (>98%) water and salt removal alongside particulate matter. This phenomenon was strikingly observed in both mild and harsh salt content conditions with concentrations ranging from zero to 200 000 ppm; the latter is found in Brazilian presalt crude oil samples. Quanti...

A simple method for the enrichment of bisphenols using boron nitride

A simple solid-phase extraction method for the enrichment of 5 bisphenol derivatives using hexagonal boron nitride (BN) was developed. BN was applied to concentrate bisphenol derivatives in spiked water samples and the compounds were analyzed using HPLC coupled to fluorescence detection. The effect of pH and organic solvents on the extraction efficiency was investigated. An enrichment factor up to 100 was achieved without evaporation and reconstitution. The developed method was applied for the determination of bisphenol A migrated from some polycarbonate plastic products. Furthermore, bisphenol derivatives were analyzed in spiked and non-spiked canned food and beverages. None of the analyzed samples exceeded the migration limit set by the European Union of 0.6mg/kg food. The method showed good recovery rates ranging from 80% to 110%. Validation of the method was performed in terms of accuracy and precision. The applied method is robust, fast, efficient and easily adaptable to different analytical problems.

Determination of Trace Amounts of Zinc, Iron and Copper by Flame Atomic Absorption after Their Preconcentration Using Sodium Dodecyl Sulfate (SDS) Coated Alumina Nanoparticles Modified with 3-Mercapto-D-Valin from Environmental Samples

A sensitive and simple solid phase extraction method for the simultaneous determination of trace and toxic metals in environmental samples has been reported. The method is based on the adsorption of Zinc, Iron and Copper on SDS-coated alumina nanoparticles, which is also modified with 3-mercapto-D-valine. The retained analyte ions on modified solid phase were eluted using 5 mL of 4 mol·L﹣1 HNO3. The analyte determination was carried out by flame atomic absorption spectrometry. The influences of some metal ion and anions on the recoveries of understudy analyte ion were investigated. The influences of the analytical parameters including pH, ligand and SDS amount, eluting solution (type and concentrations) and sample volume on metal ions recoveries were investigated. The extraction efficiency was > 98% with relative standard deviation lower than 3% the method has been successfully applied for the extraction and determination of these ions content in some real samples. Prepared adsorbent was characterized by SEM and FT-IR measurements.

Development and Validation of Liquid Chromato­graphy-Tandem Mass Spectrometric Method for Quantification of Meropenem in Rat Plasma and its Application in a Preclinical Dose Proportionality Study

A simple, rapid, sensitive and selective assay based liquid chromatography-tandem mass spectrometric method was developed and validated for quantitative analysis of meropenem in rat plasma using rolipram as internal standard. Efficient chromatographic separation of analyte from matrix components was achieved by using Kromasil 100 C18 (150×4.6 mm, 5 µm) reversed phase column with mobile phase consisting of acetonitrile and 2 mM ammonium acetate buffer (80:20, v/v) delivered in isocratic mode with constant flow rate of 0.7 mL/min. Detection of meropenem and rolipram was performed in positive mode using multiple reaction monitoring (MRM). The mass transitions 384.1→141.0 and 276.2→191.1 were used to quantify meropenem and rolipram, respectively. A fast and simple solid phase extraction method was optimized for extraction of meropenem from rat plasma. The developed method was validated for selectivity, accuracy, precision, linearity, recovery, stability, matrix effect, dilution integrity as per regulatory guidelines. The developed method was selective with no interfering components at the retention time of meropenem and rolipram. The assay demonstrated acceptable linearity (R(2)>0.99) over a dynamic range of 0.19-201.40 µg/mL. The method exhibited excellent and acceptable precision and accuracy, and produced consistent recoveries. The method demonstrated excellent stability of meropenem in rat plasma under studied conditions investigated. Finally, the validated method was successfully applied to quantify meropenem levels in rat plasma of a dose escalation study.

A rapid HPLC‐ESI‐MS/MS method for determination of β‐asarone, a potential anti‐epileptic agent, in plasma after oral administration of Acorus calamus extract to rats

β-Asarone (BAS), a phenylpropanoid from Acorus calamus Linn., has shown biological effects in the management of cognitive impairment conditions such as Alzheimer's disease. The present paper describes a selective and sensitive liquid chromatography-tandem mass spectrometric method (HPLC-MS/MS) using electrospray ionization source (ESI) for quantification of BAS in rat plasma. Briefly, the plasma samples were pre-treated using a simple solid-phase extraction method. The separation of BAS and the internal standard, caffeine, was achieved on an Agilent Zorbax XDB C(18) column (50 × 2.1 mm i.d., 5 µm) using 0.2 mL/min isocratic mobile phase flow. The detection was performed using an Applied Biosystems Hybrid Q-Trap API 2000 mass spectrometer equipped with an ESI source operated in positive mode. Also, the developed bioanalytical method was validated as per the US FDA bioanalytical guidelines over the concentration range of 9.79-4892.50 ng/mL (r(2) ≥ 0.9951) for BAS from rat plasma. The mean percentage recovery (n = 3) for the low, middle and high quality control samples was 86.92 ± 3.89, 85.30 ± 1.09 and 87.24 ± 4.03%, respectively. The applicability of the validated HPLC-MS/MS method was demonstrated by successful measurement of BAS from plasma following oral administration of Acorus calamus rhizome extracts to three female albino Wistar rats.

A liquid chromatography/electrospray ionization tandem mass spectrometric method for quantification of asiatic acid from plasma: application to pharmacokinetic study in rats

Asiatic acid (AA), a pentacyclic triterpene from Centella asiatica (L.) Urban, has shown numerous therapeutic activities. However, none of the published works to date has used high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) for determination of AA from biological fluids. Therefore, the present paper describes a sensitive HPLC/electrospray ionization (ESI)-MS/MS method for quantification of AA in rat plasma. Ammonium adduct formation of AA was essential in the development of a sensitive method with the rat plasma samples being pre-treated by a simple solid-phase extraction method. The separation was achieved on a Cosmosil C(18) column using a gradient mobile phase flow. Detection was performed using an Applied Biosystems API Q-Trap 2000 mass spectrometer equipped with an ESI source operated in positive mode with colchicine used as internal standard. An eight-point calibration curve over the concentration range of 1.02-407.88 ng/mL for AA from rat plasma provided an optimum linear detector response (with r(2) >0.9983). The mean percentage recovery (n = 3) for the low, middle and high quality control samples was 91.23 ± 1.88%, 90.36 ± 0.55% and 89.71 ± 0.21%, respectively. The intra-day and inter-day precision and accuracy of the quality control samples were within ≤5% and ±7% correspondingly. The developed method was validated as per US FDA guidelines and applicability demonstrated by successful measurement of AA from plasma following oral administration of C. asiatica extracts to Wistar rats. The results suggest that the method could be applied to therapeutic monitoring of AA and pharmacokinetic studies in human volunteers.

Solid phase extraction for GC-FID determination of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA) and methamphetamine (MA) in human urine

A simple solid phase extraction method was developed for estimating the amounts of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA) and methamphetamine (MA) in urine by using the GC-FID technique. The urine sample was alkalinized prior to undergoing solid phase extraction using Oasis HLB®. A 5% methanol-water mixture containing 2% ammonium hydroxide was used for washing, whereas a 70% methanol-water mixture containing 2% acetic acid was used for elution. The compounds were analyzed using the standard GC-FID conditions previously established for ecstasy samples, i.e., column: CP-SIL 24 CB WCOT (30 m × 0.32 mm i.d., 0.25 μm film thickness); carrier gas: N2 (2.6 mL/min); injector temperature: 290°C; detector temperature: 300°C; oven temperature: initial 80°C, final 270°C (1 min), ramp rate 20°C/min. Validation demonstrated the linearity of the calibration curves between 1 and 20 μg/mL (r > 0.99) for all analytes. The precisions (% RSD) were approximately 3–17%, 6–16% and 7–17% for MDMA, MDA and MA, respectively. The accuracies (% DEV) were (−)17-(+)5%, (−)18-(+)15% and (−)18-(+)0.6% for MDMA, MDA and MA, respectively. The recovery ranged from 80 to 107% and the lower limit of quantification (LLOQ) was 1 μg/mL. The method was successfully applied to determine the levels of these compounds in the urine of drug abuse suspects.

Separation and Purification of Sulforaphane from Broccoli by Solid Phase Extraction

A simple solid-phase extraction (SPE) method for the determination of sulforaphane in broccoli has been developed. The optimal conditions were found to be use of a silica SPE cartridge, and ethyl acetate and dichloromethane as washing and eluting solvents, respectively, which could eliminate interferences originating from the broccoli matrix. The extracts were sufficiently clean to be directly injected into high-performance liquid chromatography (HPLC) for further chromatographic analysis. Good linearity was obtained from 0.05 to 200 μg/mL (r = 0.998) for sulforaphane with the relative standard deviations less than 3.6%. The mean recoveries of sulforaphane from broccoli were more than 90.8% and the detection limit (S/N = 3:1) was 0.02 μg/mL. The SPE method provides a higher yield of sulforaphane from crude extracts compared to conventional liquid-liquid extraction.

Analysis of ciprofloxacin in low- and high-fat milk by high-performance liquid chromatography-mass spectrometry

Summary The quantitative analysis of antibiotics in different matrices is of increasing importance in in vitro studies of food-drug interactions in the drug-development process. Our objective was to develop a new, rapid and simple solid-phase extraction method without protein precipitation followed by high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) for analysis of ciprofloxacin in low- and high-fat milk. The HPLC-MS method (a single-quadrupole mass spectrometer equipped with an electrospray ion source was used as detector) was validated using a quinolone derivative, aripiprazole, as internal standard. A C8 column and gradient elution with 0.02 m ammonium acetate solution (pH 2.5) and acetonitrile mixtures (flow rate 0.5 mL min−1) were used for HPLC separation. Various modes of detection (diode-array detection and MS detection in scanning and selected-ion monitoring modes) were compared for selectivity and sensitivity of quantitative analysis of ciprofloxacin. Use of selecte...

Advances in solid phase extraction of the cyanobacterial toxin cylindrospermopsin

Unlike other cyanotoxins, cylindrospermopsin (CYN) is often found in high concentrations in the extracellular fraction, possibly due to a higher release from the producing cells and a limited degradation once liberated. This fact demands effective recovery methods from environmental samples to guarantee a proper quantification. A reliable and simple solid phase extraction (SPE) method was obtained by the sole use of graphitized carbon cartridges and by paying special attention to both the selection of the most suitable solvent and the need of sample preparation prior to SPE. An acidified combination of dichloromethane and methanol not only showed best recoveries, but also allowed drastic reduction to the elution volumes needed with complete recovery being achieved in only 8 mL. Acidification of the sample and addition of sodium chloride are suggested as valuable improvements to the SPE method and turn out to be essential for correct and robust recovery of CYN in environmental samples of great diversity in terms of pH, DOC, and conductivity. Excellent behavior of the proposed method over a wide range of CYN loadings, applied sample volumes, and DOC loadings was also confirmed.

Flame atomic absorption spectrometric determination of zinc, nickel, iron and lead in different matrixes after solid phase extraction on sodium dodecyl sulfate (SDS)-coated alumina as their bis (2-hydroxyacetophenone)-1, 3-propanediimine chelates

A sensitive and simple solid phase extraction method for the simultaneous determination of trace and toxic metals in food samples has been reported. The method is based on the adsorption of zinc, nickel, iron and lead on sodium dodecyl sulfate (SDS)-coated alumina, which is also chelated with bis (2-hydroxyacetophenone)-1, 3-propanediimine (BHAPN). The retained analyte ions on modified solid phase were eluted using 8 mL of 4 mol L −1 HNO 3. The analyte determinations were carried out by flame atomic absorption spectrometry. The influences of some metal ions and anions on the recoveries of understudy analyte ions were investigated. The proposed method has been successfully applied for the evaluation of these trace and toxic metals in some traditional food samples from Iran.

SPE/HPLC/UV studies on acrylamide in deep-fried flour-based indigenous Chinese foods

A fast and cost-effective method using HPLC/UV has been developed for determination of acrylamide in deep-fried flour-based leaven dough foods available in Hong Kong. The samples were purified by a simple solid-phase extraction method which combined Oasis HLB and Bond Elut-Accucat cartridges. The aqueous sample solution was centrifuged at 14,500 × g and 0 °C for 15 min to successfully remove the fat in the samples. A gradient elution program and a mobile phase of 4.0% v/v acetonitrile in water allowed sufficient retention and well resolved acrylamide from the food matrices in the sample extracts. Acrylamide was detected at UV wavelengths of 210 and 225 nm. The amounts of acrylamide in eight food samples were 27–198 μg/kg when 1-g samples were analyzed. The recoveries of acrylamide were larger than 78.0% and the precisions were 2.1–10.9% ( n = 3). Our proposed method is especially relevant for analyzing acrylamide in those oily food matrices.