Solid-phase Extraction Liquid Chromatography Research Articles

Synchronized Fast SPE and UFLC Methods for the Analyses of Eight Antidiabetic Drugs in Human Plasma.

The population of diabetic patients is rapidly increasing globally. The treatment of these patients is a complex phenomenon due to the use of the different drugs. The present article reports a synchronized fast SPE-UFLC separation of eight antidiabetic drugs in human plasma. Inexpensive solid phase extraction (SPE) and ultra fast liquid chromatography (UFLC) methods were presented for monitoring of eight antidiabetic drugs in human plasma. The separated drugs include metformin HCl, vildagliptin, gliclazide, linagliptin, sitagliptin, pioglitazone, glimepiride and repaglinide plasma sample. The column used was a Sunshell C18 (150 x 4.6 mm, 2.6 μ) with eluent of acetate buffer (0.05% TEA in 0.05 M NH4Ac of pH 7.0 with H 3PO4) - ACN (60 : 40, v/v). The flow rate was 1.0 mL/min with a detection wavelength of 210 nm and column temp. of 45±1ºC. These drugs were extracted from human plasma using Sep-Pac C18 cartridge. Phosphate buffer (25 mM; pH 7.0) containing these drugs were allowed to pass through cartridge at 0.1 mL/min flow rate. The adsorbed drugs on C18 cartridge were eluted by methanol at 1.0 mL/min flow rate. The values for the retention, separation and resolution factors were ranged from 0.072 to 9.140, 1.443 to 4.208 and 2.147 to 18.652, correspondingly. The percent recoveries for these drugs in the standard laboratory samples prepared in water ranged from 77 to 88%. These values in plasma samples ranged from 10 to 22%. The validated method was fruitfully adopted to analyze these drugs in human plasma for the clinical monitoring of these drugs.

High-Throughput Determination of 30 Veterinary Drug Residues in Milk Powder by Dispersive Solid-Phase Extraction Coupled with Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry

A high-throughput method was established for the simultaneous determination of 30 β-agonists, fluoroquinolones, and cephalosporins in milk powder by dispersive solid-phase extraction (dSPE) and ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Samples were firstly dissolved in sodium acetate buffer, then extracted with formic acid-acetonitrile, and subsequently purified by dSPE. Thirty target analytes were separated on a C18 column by gradient elution, detected through electrospray ionization (ESI) source in the positive mode with multi-reaction monitoring (MRM) conditions. The developed method was validated in terms of linearity, accuracy, and precision. Results indicated that 30 target analytes displayed excellent linearity in their corresponding concentration ranges and that their correlation coefficients were all higher than 0.995. The limits of quantitation (LOQs) for these targets were in the range of 0.7–7.0 μg/kg. The mean recoveries for negative sample spiked at three concentration levels were calculated between 80.0 and 97.5% with the relative standard deviation (RSD, n = 6) values ranging from 2.8 to 10.8%. In addition, the inter-day precision (n = 5) of the second spiked concentration was less than 13% (4.4–12.4%). The established and validated method is accurate and rapid and suitable for the high-throughput analysis of β-agonist, fluoroquinolone, and cephalosporin multi-residues in milk powder.

Determination of piperidinium ionic liquid cations in environmental water samples by solid phase extraction and hydrophilic interaction liquid chromatography

This paper presents a novel analytical method for the determination of piperidinium ionic liquid cations in environmental water by hydrophilic interaction liquid chromatography and solid-phase extraction technology. The left standing, centrifuged and filtered river water samples were first purified and concentrated through the C18 solid phase extraction column, and eluted with 0.02mol/L hydrochloric acid prepared in methanol and deionized water (80/20, v/v). Then the eluents were analyzed by a hydrophilic column combined with 0.8mmol/L 1-propyl-3-methyl imidazolium tetrafluoroborate aqueous solution/acetonitrile (40/60, v/v) as the mobile phase and indirect ultraviolet detection. The detection limits of piperidinium cations were less than 0.4mg/L. The relative standard deviations were less than 0.6%. The method has been successfully applied to the determination of piperidinium cations in Songhua River water samples. Recoveries were 80.0%–98.3%. This research may provide a reference for studying the environmental effect of ionic liquids.

Direct Analysis of Six Pharmaceuticals using Online Solid Phase Extraction Liquid Chromatography

In this study, three parameters (sample volume, cleanup and elution step) in large volume injection online Solid Phase Extraction Liquid Chromatography with diode array detection (SPE-LC) were optimized for the determination of six pharmaceuticals in wastewater samples. Preconcentration and separation were carried out using 2 columns, Dionex Ion Pac AG14A and Acclaim Polar Advantage II. Response Surface Methodology (RSM) was employed for the optimization of cleanup step (mobile phase composition and valve switching time). The optimum conditions obtained were as follows: Sample volume of 10.0 mL and cleanup with acetonitrile and ultrapure water (5:95) for 1.0 min. The method showed good recovery (82.91-107.7%), precision (0.35-8.26%) and linearity (R2 >0.99). The limit of detection was between 3.5 and 11.7 μg L-1. The proposed method is rapid, simple and sensitive for trace analysis of pharmaceuticals in water samples.

Occurrence and behaviour of pharmaceutical compounds in a Portuguese wastewater treatment plant: Removal efficiency through conventional treatment processes.

Wastewater treatments can eliminate or remove a substantial amount of pharmaceutical active compounds (PhACs), but there may still be significant concentrations of them in effluents discharged into surface water bodies. Beirolas wastewater treatment plant (WWTP) is located in the Lisbon area and makes its effluent discharges into Tagus estuary (Portugal). The main objective of this study is to quantify a group of 32 PhACs in the different treatments used in this WWTP. Twelve sampling campaigns of wastewater belonging to the different treatments were made in 2013-2014 in order to study their removal efficiency. The wastewaters were analysed by solid phase extraction (SPE) and ultra-performance liquid chromatography coupled with tandem mass detection (UPLC-MS/MS). The anti-diabetics were the most frequently found in wastewater influent (WWI) and wastewater effluent (WWE) (208 and 1.7μg/L, respectively), followed by analgesics/antipyretics (135μg/L and < LOQ, respectively), psychostimulants (113 and 0.49μg/L, respectively), non-steroidal anti-inflammatory drugs (33 and 2.6μg/L, respectively), antibiotics (5.2 and 1.8μg/L, respectively), antilipidemics (1.6 and 0.24μg/L, respectively), anticonvulsants (1.5 and 0.63μg/L, respectively) and beta blockers (1.3 and 0.51μg/L, respectively). A snapshot of the ability of each treatment step to remove these target PhACs is provided, and it was found that global efficiency is strongly dependent on the efficiency of secondary treatment. Seasonal occurrence and removal efficiency was also monitored, and they did not show a significant seasonal trend.

DEVELOPMENT OF A TECHNIQUE FOR THE MASS-SPECTROMETRIC DETERMINATION OF GONADOTROPIN-RELEASING HORMONE AND ITS ANALOGS FOR DOPING CONTROL

In the present study, a rapid, sensitive, and selective method for determination of several synthetic analogues of gonadotropin-releasing hormone in human urine by solid-phase extraction and ultraperformance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) was developed. Various parameters affecting sample preparation, LC separation, and MS/MS detection were investigated, and optimized conditions were identified. The UPLC-MS/MS system was equipped with an electrospray ion source operating in positive ion mode with selected reaction monitoring. Leuprolide-13С6 was used as internal standard for analytes quantitative assessment. The proposed method was validated considering the parameters specificity, linearity (0.1-10 ng/ml), recovery (52-98%), limit of detection (0.1 ng/ml), matrix effects and stability.

Analysis of microcystins using high-performance liquid chromatography and magnetic solid-phase extraction with silica-coated magnetite with cetylpyridinium chloride.

Microcystins (MCs), produced by freshwater cyanobacteria, can be serious water pollutants, so it is important to monitor their concentration in drinking water. We have developed a method for rapid and accurate determination of microcystin levels in environmental water, using magnetic solid-phase extraction and high-performance liquid chromatography with UV detection. The magnetic composite material, which was combined with cetylpyridinium chloride, was prepared by hydrothermal synthesis. The optimal extraction of microcystins in water sample was achieved by optimizing the amount of adsorbent, time of adsorption, ratio of eluting solvent, and volume of eluent. Under the optimal conditions, the limit of detection of MC-LR was 0.001μg/L, and the limit of quantification was 0.0028μg/L. The limit of detection of MC-RR was 0.001μg/L, and the limit of quantification was 0.003μg/L. These values are far lower than those established by the International Health Organization for the maximum concentration of microcystins in drinking water. The magnetic solid-phase extraction adsorbent used in this method has the advantages of simple preparation, low price, and easy solid-liquid separation, and it can be used for the rapid and sensitive monitoring of trace microcystins in environmental water samples.

Multiresidue analysis of 24 Water Framework Directive priority substances by on-line solid phase extraction-liquid chromatography tandem mass spectrometry in environmental waters

This paper reports the development of a fully multiresidue and automated on-line solid phase extraction (SPE) – liquid chromatography tandem mass spectrometry (LC–MS/MS) method for the determination of 24 priority substances (PS) belonging to different classes (pesticides, hormones or pharmaceuticals) included in the Directive 2013/39/UE and the recent Watch List (Decision 2015/495) in water samples (drinking water, surface water, and effluent wastewaters). LC–MS/MS conditions and on-line SPE parameters such as sorbent type, sample and wash volumes were optimized. The developed method is highly sensitive (limits of detection between 0.1 and 1.4ngL−1) and precise (relative standard deviations lower than 8%). As part of the method validation studies, linearity, accuracy and matrix effects were assessed. The main advantage of this method over traditional off-line procedures is the minimization of tedious sample preparation increasing productivity and sample throughput.The optimized method was applied to the analysis of water samples and the results revealed the presence of 16 PS in river water and effluent water of wastewater treatment plants.

Determination of Tetracyclines in Milk by Graphene-Based Solid-Phase Extraction and High-Performance Liquid Chromatography

ABSTRACTA graphene-based solid-phase extraction (SPE) column was prepared for the isolation of tetracyclines from milk followed by determination by high-performance liquid chromatography. Graphene provided better separation for tetracyclines than amine-modified graphene and carboxyl-modified graphene. The optimized graphene-based SPE column showed high absorption capacities (greater than 4,660 ng) and high recoveries (exceeding 92%) for tetracycline, oxytetracycline, chlortetracycline, and doxycycline and was successfully reused at least fifty times. The limits of detection in milk were from 10 to 20 ng/mL, with recoveries between 82.3 and 103.6%. Furthermore, the system showed superior performance than two commercial SPE cartridges with respect to recovery, purification, and reusability. Therefore, this approach is suitable for the determination of tetracyclines in milk.

Occurrence of Veterinary Antibiotics in Swine Manure from Large-scale Feedlots in Zhejiang Province, China.

The occurrence and distribution of five sulfonamides and three tetracyclines in swine manure sampled from large-scale feedlots in different areas of Zhejiang Province, China were detected using solid-phase extraction and high-performance liquid chromatography. All eight test antibiotics were detected in most of the manure samples. The dominant antibiotics in swine manure were sulfadiazine, sulfamerazine, sulfadimidine, tetracycline, and chlortetracycline. The maximum concentration of residual antibiotic reached up to 57.95mg/kg (chlortetracycline). The concentrations and distribution of both types of antibiotics in swine manure of different areas varied greatly. Relatively higher concentrations of sulfonamides were found in swine manure from the Zhejiang area in this experiment compared with previous studies. The results revealed that antibiotics were extensively used in feedlots in this district and that animal manure might act as a non-specific source of antibiotic residues in farmlands and aquatic environments.

Simultaneous determination of bisphenol A, chlorophenols and alkylphenols by solid-phase extraction and HPLC

An analytical method for determining potential endocrine disruptors (bisphenol A, 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol, p-t-butylphenol, p-pentylphenol, p-hexylphenol, pt-octylphenol, p-heptylphenol, nonylphenol) by solid-phase extraction (SPE) and High Perfomance Liquid Chromatography(HPLC) equipped with fluorescence and variable wavelength detector has been developed. The SPE process for sample concentration was performed on a commercially available Oasis HLB cartridge packed with polymeric sorbents. The effect of elution solvent and elution volume on the recoveries of the analytes were investigated with HPLC. Average recovery of >85% was achieved with 60mg sorbents using 5mL of methanol as elution solvent. Phenolic compounds in canned drinks, beverages and water samples were surveyed by this proposed method.

The use of caffeine as a chemical marker of domestic wastewater contamination in surface waters: seasonal and spatial variations in Teresópolis, Brazil

This study assessed the suitability of caffeine as an indicator for surface water pollution by domestic wastewaters. Caffeine concentrations determined in samples collected in the Paquequer River, located at the city of Teresópolis, a medium-sized city in the State of Rio de Janeiro, Brazil, were compared to other conventional water quality parameters such as phosphate, nitrate and ammonium concentrations to determine whether it as an efficient indicator of anthropic pollution of an urban aquatic environment. The Paquequer River originates in a pristine area called Parque Nacional da Serra dos Órgãos (PARNASO) and it crosses the urban area of the city of Teresópolis. Water samples were collected at seven points along the river, considering the periods of rain (summer) and drought (winter) and the different uses of land. Caffeine was measured using Solid Phase Extraction (SPE) and High Performance Liquid Chromatography (HPLC). Caffeine concentrations were found in a range from 0.16 to 47.5 µg L-1. The results show a positive relation between caffeine, phosphate, nitrate and ammonium concentrations and the increase of wastewater load, suggesting that caffeine can be used as an indicator of surface water pollution by domestic wastewaters.

Analysis of Glycocholic Acid in Human Plasma and Urine from Hepatocellular Carcinoma Patients

Glycocholic acid (GCA) has been identified as endogenous biomarker for hepatocellular carcinoma (HCC). To dissolve protein and liberate GCA from protein, ionic liquids (ILs) that contain chaotropic ions were used for pretreatment of liquid biological samples. Coupling with solid-phase extraction (SPE) and reversed-phase high-performance liquid chromatography (RP-HPLC), the novel sample pretreatment method was applied for quantitative determination of GCA in urine and plasma samples. Compared with the traditional organic solvents pretreatment of biological samples, the proposed method is “greener” and simpler, due to no use of volatile organic solvent, and avoiding centrifugation. Under the optimal conditions, when the GCA-free urine and plasma samples were spiked with GCA at 0.05–1.0 and 0.2–10 μmol L−1, the recoveries of GCA ranged between 95.8–101.6 and 96.9–100.4%, respectively. These procedures only required 1 mL of urine and 3 mL of 3 mM ILs aqueous solution and 100 μL of plasma and 4 mL of 2 mM ILs aqueous solution, respectively. The proposed method has been successfully validated on a small sample size of 14 HCC patients and 14 healthy volunteers. For HCC patients, the mean concentration of GCA was 24.79 ± 6.86 and 31.98 ± 11.12 μmol L−1 in urine and plasma samples, and was about 3 times and 24 times as much as in healthy people, respectively. The proposed method opens up a new possibility in early diagnosis of HCC.

Characteristics and ecological risk assessment of antibiotics in five city lakes in Nanchang City, Lake Poyang Catchment

采用固相萃取-超高效液相色谱-质谱法对南昌市5个城市湖泊——艾溪湖、瑶湖、青山湖、象湖和东西湖水体的抗生素进行监测，并分析其污染来源和生态风险. 结果表明，南昌市5个城市湖泊水体中四环素类、磺胺类、喹诺酮类、林可霉素及大环内酯类5类抗生素的检出浓度范围分别为ND~6.3、ND~32.0、ND~97.2、ND~54.7和ND~98.4 ng/L；红霉素和林可霉素是5个城市湖泊水体中的主要抗生素类型；相比于其他湖泊，南昌市城市湖泊水体中主要检出抗生素浓度总体处于中等水平，其中恩诺沙星的检出浓度高于其他对比湖泊. 南昌市城市湖泊中6种主要抗生素的风险商均小于0.1，表明均为最低生态风险；5个城市湖泊的主要生态风险因子分别是艾溪湖为红霉素，瑶湖为磺胺二甲嘧啶，青山湖为罗红霉素，象湖为红霉素，东西湖为磺胺嘧啶. 本研究可为南昌市城市湖泊水环境管理，特别是新型污染物的环境管理提供基础依据.;Antibiotic concentrations in the five urban lakes in Nanchang City were monitored with methods of solid phase extraction and high performance liquid chromatography tandem mass spectrometry. The sources of antibiotics were analyzed and ecological risk of typical antibiotics on fish, invertebrates and algae were assessed using Risk Quotients (RQs). Results showed that, the detected concentration range of tetracyclines, sulfonamides, quinolones, lincomycin and macrolides were ND-6.3 ng/L, ND-32.0 ng/L, ND-97.2 ng/L, ND-54.7 ng/L and ND-98.4 ng/L, respectively. Erythromycin and lincomycin were the main antibiotic types in the lakes. The antibiotic concentration detected in the five lakes were in the medium level compared with other lakes. The detected concentration of enrofloxacin was relatively higher than that in other lakes. RQs of the six main detected antibiotics were all less than 0.1, indicating the lowest ecological risk. The main ecological risk factors of the five lakes were erythromycin, sulfadimidine, roxithromycin, erythromycin and sulfadiazine respectively in Lake Aixi, Lake Yao, Lake Qingshan, Lake Xiang and Lake East-west. This study provides basis for water environment management, especially for controlling emerging pollutants in such urban lakes.

Packed-nanofiber solid phase extraction coupled with HPLC for the determination of chloramphenicol in milk

A sensitive analytical method based on packed-nanofiber solid phase extraction (PFSPE) and high performance liquid chromatography (HPLC) has been developed for determining chloramphenicol (CAP) in milk.

Simultaneous determination of nine perfluorinated compound precursors in atmospheric precipitation by solid phase extraction and ultra performance liquid chromatography with tandem mass spectrometry

A high-throughput detection method has been developed for the determination of nine perfluorinated compound precursors (PFCPs) in atmospheric precipitation by solid phase extraction-ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (SPE-UPLC-ESI-MS/MS). The atmospheric precipitation samples were concentrated and purified with HLB solid phase extraction cartridges. The UPLC separation was performed on an HSS T3 column (100 mm×2.1 mm, 1.7 μm) utilizing a gradient elution program of methanol and water as the mobile phases at a flow rate of 0.2 mL/min. The MS/MS detection was performed under negative electrospray ionization (ESI-) in multiple reaction monitoring (MRM) mode. Good linearity was observed in the range of 0.05-5.00 μg/L, 0.50-50.0 μg/L or 5.00-500 μg/L with correlation coefficients from 0.9921 to 0.9995. The limits of detection (LODs) for the nine perfluorinated compound precursors were in the ranges of 0.05-7.9 ng/L. The recoveries ranged from 76.0% to 106% with the relative standard deviations between 0.72% and 13.7%. This method is characterized by high sensitivity and precision, extensive analytical range and quick analytical rate, and can be applied for the analysis of perfluorinated compound precursors in atmospheric precipitation.

Extraction optimization of sixteen cephalosporins in milk by filtered solid phase extraction and ultra high pressure liquid chromatography coupled to tandem mass spectrometry

A method employing a type of filtered solid phase extraction based on the PRiME hydrophilic lipophilic balance (HLB) was developed for extracting cephalosporin compounds from milk samples.

Aqueous Ultrasound-Assisted Extraction for the Determination of Fluoroquinolones in Mangrove Sediment by High-Performance Liquid Chromatography and Fluorescence Detector

A method for simultaneous analysis of ciprofloxacin (CIP), levofloxacin (LEV) and norfloxacin (NOR) in mangrove sediment was developed using aqueous ultrasound-assisted extraction (UAE), solid phase extraction (SPE) and high-performance liquid chromatography with fluorescence detection (HPLC-FD). The method showed excellent linear correlation coefficient for the three fluoroquinolones (r2 > 0.999) using external calibration curve and good recovery in real sediment samples ranging from 73.73 to 88.85%. The precision showed a relative standard deviation lower than 20% and detection limits of 1.10, 3.33 and 0.26 µg kg-1 to CIP, LEV and NOR, respectively. There was no presence of interfering. After validation, the method was applied in the determination of pharmaceuticals in mangrove sediment in the Paciencia River, Maranhao Island, Brazil. Only the CIP antibiotic was found in three of six samples analyzed, with values ranging 56.55-70.45 µg kg-1.

Detection of reactive aldehyde biomarkers in biological samples using solid-phase extraction pre-concentration and liquid chromatography with fluorescence detection

Fluorescence derivatization allows for detection of lipid peroxidation biomarkers of epilepsy-induced oxidative stress.

A graphene tip coupled with liquid chromatography tandem mass spectrometry for the determination of four synthetic adulterants in slimming supplements.

Slimming supplements were popularly sold online driven by the increasement of obesity and the development of social networking platform. However, events of drug abuse in slimming supplements were also frequently reported. In this study, a graphene tip solid-phase extraction (Gtip SPE) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established for determining fenfluramine, phenolphthalein, bumetanide, and sibutramine in slimming supplements. It was validated in terms of linearity (0.9985-0.9995), LOD (1.8ngmL-1), LOQ (5.6ngmL-1), intra-day precision (<5.1%), inter-day precision (<7.3%), and recovery (82.9-95.2%). Sibutramine is the most commonly used drug, which was detected in Bihais, Galong, and Aolist, with content 12.4, 3.6, 20.3mgg-1, respectively. Phenolphthalein was also found with content lower than 5.2mgg-1. The successful application of Gtip SPE and UPLC-MS/MS method indicated its advantage in analyzing low level of contaminates resulted from violation of regulation.