Semi-automated Solid-phase Extraction Research Articles

Rapid green analytical methodology for simultaneous monitoring of nitrosamines and semi-volatile organic compounds in water and human urine samples.

Nitrosamines and semi-volatile organic compounds (SVOCs) are carcinogenic contaminants in water and biological matrices. Conventional analytical methods often struggle to detect trace concentrations due to poor extraction efficacies. This study presents a novel, low-cost, in-syringe-assisted fast extraction cum cleanup technique coupled with GC-FID for monitoring four nitrosamines and two SVOCs in drinking water and human urine samples to measure the contamination and exposure levels. This extraction protocol combines a novel green in-syringe liquid-liquid extraction step using dimethyl carbonate as the green extraction solvent, coupled with a semi-automated solid-phase extraction cleanup process. Then, the final extractant is analyzed using gas chromatography-flame ionization detection (GC-FID) for monitoring. The method demonstrated excellent linearity (R2 > 0.998) between 1.5 and 500ngmL⁻1 for all six target compounds. Detection limits ranged from 1.0 to 2.0ngmL⁻1. Extraction recoveries were between 87 and 105% for both urine samples and water samples. Intra-day and inter-day precision were below 9% RSD. The blue applicability grade index evaluation scored 70.0, indicating good practical applicability. The developed analytical protocol offers a sensitive, accurate, low-cost, rapid, and environmentally friendly method for simultaneously quantifying multiple nitrosamines and SVOCs in environmental and human samples. Its performance characteristics and sustainability metrics suggest the potential for broad application in monitoring and exposure studies.

A Semi-Automated Molecularly Imprinted Polymer Solid-Phase Extraction Method for Catechin Analysis from Jaboticaba (Plinia sp.) Peel Extract Samples by UHPLC-DAD

Jaboticaba (Plinia sp.), a nutritionally significant Brazilian fruit, is rich in phenolic compounds, such as catechin, known for its biological and pharmaceutical properties. Extracting and studying these compounds is an economic and environmental strategy to fully explore the great potential that these chemical compounds have. Therefore, this study focuses on developing a semi-automated solid-phase extraction method using molecularly imprinted polymer for catechin analysis in jaboticaba peel extracts, coupled with an ultra-high-performance liquid chromatography with a diode array detector. The reported polymer demonstrated superior extractor capacity compared to the non-imprinted polymer. Different extraction parameters were optimized, and the method exhibited a linear range of 10 to 100 µg mL-1 for catechin. The obtained precision with the coefficient of variation was below 7.3%, and the limits of quantification and detection were 12.4 and 4.1 µg mL-1 , respectively. The developed sorbent maintained analytical performance through approximately 40 injections. Results suggest that the reported method could efficiently extract catechin from jaboticaba peels in less than 10 min, providing a promising tool for the rapid investigation of natural products. This selective and sustainable approach demonstrated here contributes to the economic and environmental aspects of catechin extraction and analysis in jaboticaba fruit.

Dispersion and stratification of Per-and polyfluoroalkyl substances (PFAS) in surface and deep-water profiles: A case study of the Biscayne Bay area

Per-and polyfluoroalkyl substances (PFAS) are a group of synthetic chemical compounds known for their persistent, bioaccumulation and toxic characteristics in all environmental compartments. As industrial and domestic applications of PFAS increase, their discharge into water bodies becomes of human and ecological concerns. Our research focuses on providing better understanding on the occurrence, vertical distribution, and dispersion of PFAS in surface and bottom water from inshore and offshore area of Biscayne Bay, Miami, Florida. We screened a total of 30 PFAS from inshore (N = 38) and offshore (N = 48) water samples using a semi-automated solid phase extraction (SPE) followed by instrumental analysis using Liquid chromatography-mass spectrometry techniques (LC-MS/MS). Our findings show a general surface-enrichment and depth-depletion pattern from inshore to offshore area. Average ∑PFAS loadings inshore (surface vs bottom; 29.52 ± 15.26 ng/L vs 21.45 ± 7.85 ng/L) is significantly greater than offshore (surface vs bottom; 5.18 ± 2.68 ng/L vs 2.42 ± 2.11 ng/L). PFOS had the highest mean concentration both inshore (6.36 ± 4.23 ng/L) and offshore (0.83 ± 0.87 ng/L). The most frequently detected (D·F > 91 %) PFAS are Perfluorooctane sulfonic acid (PFOS), Perfluorooctanoic acid (PFOA), Perfluoroheptanoic acid (PFHpA), Perfluorohexanoic acid (PFHxA), Perfluorobutanoic acid (PFBA), Perfluorobutane sulfonic acid (PFBS) and Perfluorohexane sulfonic acid (PFHxS) in surface water samples. PFOS/PFOA >1 suggests that point sources are the major contribution to PFAS burden in the Biscayne Bay. An innovative Inverse distance weighted interpolation (IDW) special modelling approach was implemented to predict the potential contribution of oceanic current on the dispersion of ∑PFAS loadings in surface and bottom profiles from canals (inshore) to offshore areas. This will provide insights into transport mechanisms of PFAS from source emissions, and risk assessments of potential impacts on human and aquatic life in the Bay.

Electrospun mesh pattern of polyvinyl alcohol/zirconium-based metal-organic framework nanocomposite as a sorbent for extraction of phthalate esters

Herein, an electrospun composite polyvinyl alcohol/zirconium-based metal-organic frameworks (PVA@UiO-66) nanofiber coating was prepared on the surface of stainless steel mesh (SSM) and then utilized as novel sorbent for the extraction of phthalate esters (PEs) in milk and water samples. Gas chromatography equipped with a flame ionization detector (GC–FID) was used for the quantitative determination of extracted analytes. The SSM coated with PVA@UiO-66 was used in a polypropylene syringe to fabricate the solid-phase extraction (SPE) device. The PVA@UiO-66 nanofiber coating was confirmed using X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy analysis (FT–IR), and field emission scanning electron microscopy (FESEM). The effective parameters of the extraction efficiency including volume and type of desorption solvent, sample volume, ionic strength, pH, extraction flow rate, and desorption flow rate were optimized. At the optimal extraction conditions, the calibration plots for phthalate esters were linear within the range of 0.05–100 ng mL−1 and, low detection limits (0.015–0.06 ng mL−1). Finally, this semi-automated SPE was used for the extraction and detection of phthalate esters (PEs) in milk and various environmental real water samples. The results showed good precision with acceptable and satisfactory extraction recovery values ranging from 89.5 to 99.2% and relative standard deviations (RSDs%) ranging from 4.5 to 6.9%.

A selective and sensitive colorimetric method for semi-automated solid-phase extraction of atrazine in environmental water samples

A selective and sensitive procedure for the trace analysis of atrazine (ATZ) in surface water samples was developed using the semi-automated solid-phase extraction (SPE) coupled with a colorimetric method. In this work, we developed Konig’s reaction using p-anisidine as a new coupling agent to form a red-colored dye product having λmax 500 nm and tuned the reaction conditions to occur at 40 °C. The possible structure of the orange-red dye product was proposed based on HPLC-UV and UPLC-MS analyses. Under the optimized conditions, the method provided linearity range of 10–30 µg/L with a good coefficient of determination (R2 > 0.99) in different sample matrices. The limit of detection and limit of quantification were 2.49 and 7.54 µg/L, respectively. The method validity was evaluated by analyzing the ATZ spiked samples collected from paddy fields, fish farms, and natural canal waters with a recovery range of 104–119 %, and the results were in good agreement with those obtained using HPLC-UV. The developed method was able to reduce the requirement of high heating temperature for the conventional Konig’s reaction and was expected to be used for the practical analysis of ATZ at the ppb levels in natural water.

A Simple, Efficient, Eco-Friendly Sample Preparation Procedure for the Simultaneous Determination of Hormones in Meat and Fish Products by Gas Chromatography-Mass Spectrometry.

Food safety can be severely compromised by the presence of chemical contaminants. This has raised a pressing need to develop efficient analytical methods for their determination at very low levels in complex food matrices. In this manuscript, we developed a simple, sensitive, fast, green analytical method for the determination of thirteen natural and synthetic hormones from different families including progestogens, estrogens and androgens in meat and fish products. The method involves direct extraction with a (9:1) acetonitrile–water mixture and subsequent purification of the extract by semi-automated solid-phase extraction on a sorbent column (hydrophilic–lipophilic copolymer of N-vinylpyrrolidone and divinylbenzene). This treatment enriches samples with the target compounds while removing proteins, lipids and other potential interferences from their matrix for the accurate determination of the analytes by gas chromatography–mass spectrometry, all within 15 min. The proposed method exhibits good linearity (r ≥ 0.996), low limits of detection (0.4–15 ng/kg), acceptable recoveries (90–105%) and relative standard deviations (≤7%); in addition, it is scarcely subject to matrix effects (1–20%). The method was successfully used to determine natural and synthetic hormones in meat and fish products from Spain, Portugal, Italy, Germany, Greece, Norway, Morocco and the USA. The analytes were found at especially high levels (30–1900 ng/kg) in mussels, beef and pork.

Trace-Level Determination of Polycyclic Aromatic Hydrocarbons in Dairy Products Available in Spanish Supermarkets by Semi-Automated Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry Detection.

Polycyclic aromatic hydrocarbons (PAHs) have been classified as priority pollutants by the U.S. Environmental Protection Agency (EPA) and the European Commission on the grounds of their carcinogenic, mutagenic and teratogenic properties. Because of their ubiquity in industrial processes and the environment, PAHs can reach milk and dairy products and, eventually, humans. In this work, a new method was developed to detect and quantify sixteen of the EPA’s priority PAHs in commercial milk and dairy products. The method involves liquid–liquid extraction (LLE) followed by semi-automated solid-phase extraction (SPE) to clean up and preconcentrate the analytes prior their detection and quantification by gas chromatography–mass spectrometry (GC–MS). The proposed method provided high precision (relative standard deviation < 11.5%), recoveries of 80–107% and low detection limits (1–200 ng/kg). The method was applied to analyze 30 dairy products, the majority of which contained some PAH at concentrations from 7.1 to 1900 ng/kg. The most-detected analytes were the lighter PAHs (naphthalene, acenaphthylene, fluorene and phenanthrene). None of the samples, however, contained more than four PAHs.

Semi-automated solid-phase extraction of polycyclic aromatic hydrocarbons based on stainless steel meshes coated with metal–organic framework/graphene oxide

In this study, Cu-based metal–organic framework/graphene oxide (Cu–MOF/GO) nanocomposite was coated on the stainless steel mesh (SSM) as a sorbent using the sol–gel method and it was used for the semi-automated solid-phase extraction (SPE) of polycyclic aromatic hydrocarbons (PAHs) from water samples. The detection of extracted PAHs was done by gas chromatography-flame ionization detection (GC–FID). The coated SSM is placed on a polypropylene syringe as a cartridge and connected to the peristaltic pump for the semi-automated SPE procedure. All parameters with significant effects on the extraction efficiency including, the volume of sample, elution solvent and its volume, salt amount, number of sample solution cycles, and elution solvent cycles on the cartridge were investigated to achieve the best experimental conditions. Under the optimized extraction conditions, the semi-automated SPE–GC–FID method demonstrated good linearity in the range of 0.001–30 ng mL−1 and, low limits of detection (0.3–1.8 pg mL−1) and, limits of quantification (0.001–0.006 ng mL−1). The sorbent was successfully applied to preconcentrate PAHs from real water samples and showed good accuracy with the relative recoveries in the range of 95.1–99.5% and the relative standard deviations (RSDs %) values were obtained in the range of 4.9 to 6.9%.

Assessment of per- and polyfluoroalkyl substances in Biscayne Bay surface waters and tap waters from South Florida

Per- and polyfluoroalkyl substances (PFAS) are persistent anthropogenic pollutants present in many environmental media worldwide due to their extensive uses in many industrial and commercial products combined with their high thermal and chemical stabilities. Its ubiquitous presence in surface and drinking water supply and significant adverse health effects observed in wildlife and humans, associated with its bioaccumulation potential, pose big concerns. In this study, we have developed and validated a semi-automated solid phase extraction (SPE) followed by liquid chromatography–mass spectrometry (LC-MS/MS) for the determination of legacy and emerging short-chain PFAS substitutes in surface and tap water at low parts-per-trillion (ppt) levels in South Florida environments. Surface waters from Biscayne Bay and adjacent canals (n = 15) and tap waters from different counties (Miami-Dade, Broward, and Palm Beach County) (n = 21) were collected between October 2020 (wet season) and February 2021 (dry season). Total PFAS concentrations up to 242 ng L-1 (average of 168 ng L-1) were found in tap water from Grapeland Heights, which is the closest location to the Miami international airport that was sampled. The highest average total PFAS level of 106 ng L-1 was observed in surface water from the Biscayne Canal C-8 for the wet and dry season. In general, average total PFAS was higher in tap water (86.3 ng L-1) than in surface waters (46.3 ng L-1), whereas the most predominant and frequently detected PFAS were PFBA, PFBS, PFPeA, PFHxA, PFHxS, PFOA and PFOS. PFAS levels found could represent a high human health risk, and ecological risk based on PFOS levels above recommended thresholds are also noted. Such knowledge on PFAS occurrence, distribution and sources in South Florida will provide essential information for local and regional regulatory agencies related to water quality, further facilitating the development of guidelines and procedures for PFAS pollution control and reduction in Florida.

Assessing polycyclic aromatic hydrocarbons in cereal-based foodstuffs by using a continuous solid-phase extraction system and gas chromatography–mass spectrometry

Polycyclic aromatic hydrocarbons (PAHs) are a family of sixteen compounds of which are deemed priority pollutants by the European Commission and the US Environmental Protection Agency for their carcinogenic and mutagenic properties. A method for their determination in a variety of cereal-based foodstuffs including bread, cookies, flours and cereals is reported here. The method uses solid–liquid extraction with a semi-automated solid-phase extraction system to clean up sample extracts, and gas chromatography–mass spectrometry to determine and quantify the target analytes. The analytical figures of merit of the proposed method, which include high precision, sensitivity and selectivity for all 16 PAHs, testify to its robustness. Thus, the limits of detection for 1 g of sample span the range from 2 to 60 ng kg−1, relative standard deviations are all lower than 7.5% and recoveries range from 88 to 103%. The method was successfully applied to several cereal-based foodstuffs samples. The European Commission has set a tolerated limit of 1 μg kg−1 for PAH4 [a combination of benzo(a)pyrene, benzo(a)anthracene, benzo(b)fluoranthene and chrysene] in cereal products for infants that was exceeded by three breakfast cereal foodstuffs (3.1–7.5 μg kg−1). Also, home toasting bread was found to raise the concentrations of some PAHs above the allowable levels.

High-throughput method of dioxin analysis in aqueous samples using consecutive solid phase extraction steps with the new C18 Ultraflow™ pressurized liquid extraction and automated clean-up

A high-throughput analytical method has been developed for the determination of seventeen 2,3,7,8-substituted congeners of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in aqueous samples.A recently introduced octadecyl (C18) disk for semi-automated solid-phase extraction of PCDD/Fs in water samples with a high level of particulate material has been tested for the analysis of dioxins. A new type of C18 disk specially designed for the analysis of hexane extractable material (HEM), but never previously reported for use in PCDD/Fs analysis. This kind of disk allows a higher filtration flow, and therefore the time of analysis is reduced. The solid-phase extraction technique is used to change samples from liquid to solid, and therefore pressurized liquid extraction (PLE) can be used in the pre-treatment. In order to achieve efficient purification, extracts from the PLE are purified using an automated Power-prep system with disposable silica, alumina, and carbon columns. Quantitative analyses of PCDD/Fs were performed by GC–HRMS using multi-ion detection (MID) mode. The method was successfully applied to the analysis of water samples from the wastewater treatment system of a vinyl chloride monomer plant. The entire procedure is in agreement with EPA1613 recommendations regarding the blank control, MDLs (method detection limits), accuracy, and precision. The high-throughput method not only meets the requirements of international standards, but also shortens the required analysis time from 2weeks to 3d.

Analytical method for biomonitoring of perfluoroalkyl acids in human urine

Perfluoroalkyl acids are an important class of synthetic compounds widely used in commercial and residential settings, which may have potential adverse health effects. The objective of this study was to monitor 6 perfluorocarboxylic acids and perfluorooctane sulphonate in human urine to obtain a way to asses exposure. The target analytes were extracted from urine by using a semi automated solid-phase extraction module and derivatised with isobutyl chloroformate by catalysis with 3% N,N-dicyclohexylcarbodiimide in pyridine. Determination and quantisation were achieved by gas chromatography with a mass spectrometer detector operating in the selected-ion monitoring mode. The developed approach is fast and provided low limits of detection (0.2–1.0ngL−1) with good precision (relative standard deviation lower than 7.5%, within-day and between day). Recoveries from urine samples, which were spiked with the studied compounds at levels of 10 and 50ngL−1 ranged from 93% to 96%. Perfluorohexanoic (≤70ngL−1) and perfluoroheptanoic acids (<2ngL−1) were found in the urine samples from exposed researchers taken after handling these compounds. From the calculation of the excretion kinetics it was found that the dosage absorbed was eliminated within 15h after exposure.

Semiautomated solid-phase extraction followed by derivatisation and gas chromatography–mass spectrometry for determination of perfluoroalkyl acids in water

This paper describes a sensitive approach for the determination of 6 perfluoroalkyl carboxylic acids and perfluorooctane sulfonic acid in water. Samples were preconcentrated using an automatic solid-phase extraction module and then manually derivatised and determined by gas chromatography–mass spectrometry. The analytes were derivatised with a isobutyl chloroformate/isobutanol mixture, using 3% N,N-dicyclohexylcarbodiimide in pyridine as the catalyst. From a systematic comparison of several reversed-phase and anion-exchange sorbent materials for the retention of perfluoroalkyl acids, the highest retention efficiencies (∼100%) were achieved with LiChrolut EN and Discovery DSC-SAX columns. LiChrolut EN was the sorbent selected due to several advantages (sample pH ∼1; sample flow rate, 5.5mL/min; breakthrough volume, 300mL) over Discovery DSC-SAX (sample pH ∼6; sample flow rate, 3.0mL/min; breakthrough volume, 45mL), for the retention of the studied compounds. Detection and quantification limits within the range of 0.1–0.5ng/L and 0.4–1.7ng/L, respectively, were obtained for a sorbent column of 70mg of LiChrolut EN and 250mL of sample, the relative standard deviation being lower than 7%. The method was applied both to the analysis of water collected at the intake (raw) and at the exit (treated) of two drinking water treatment plants, as well as to various types of water. Few samples were positive for perfluoroalkyl acids and only one acid (perfluoroheptanoic or perfluorooctanoic) was found in each treatment plant. The highest number and concentration of analytes (perfluoroheptanoic, perfluorooctanoic and perfluorodecanoic acid) were found in one wastewater.

Semiautomated solid-phase extraction manifold with a solvent-level sensor

A semiautomated solid-phase extraction manifold for multiple extractions is presented. The manifold utilizes commercial solid-phase syringe cartridges and automatically introduces and elutes all the solvents during the extraction, reducing the typical workload and stress of the analyst. The manifold consists of a peristaltic pump with solenoid valves in a flow circuit that contains transmissive photomicrosensors. The photomicrosensors were used to control the solvent dispenser and the solvent level inside the cartridge. As solvent-level sensors, the photomicrosensors determined the exact time the solvent reached the top frit to avoid sorbent drying and accurately perform the solvent exchange. The repeatability of the manifold to introduce a particular volume of solvent into the cartridges was measured, and the precisions were between 0.05 and 2.89% (RSD). To evaluate the manifold, the amount of two fluoroquinolones in a fortified blank milk sample was determined. The results of the intra- and inter-day precision of multiple extractions from the fortified milk samples resulted in precisions better than 9.0% (RSD) and confirmed that the arrangement of the semiautomated manifold could adequately be used in solid-phase extraction with commercial cartridges.

Semi-automated solid phase extraction method for the mass spectrometric quantification of 12 specific metabolites of organophosphorus pesticides, synthetic pyrethroids, and select herbicides in human urine

Organophosphate and pyrethroid insecticides and phenoxyacetic acid herbicides represent important classes of pesticides applied in commercial and residential settings. Interest in assessing the extent of human exposure to these pesticides exists because of their widespread use and their potential adverse health effects. An analytical method for measuring 12 biomarkers of several of these pesticides in urine has been developed. The target analytes were extracted from one milliliter of urine by a semi-automated solid phase extraction technique, separated from each other and from other urinary biomolecules by reversed-phase high performance liquid chromatography, and detected using tandem mass spectrometry with isotope dilution quantitation. This method can be used to measure all the target analytes in one injection with similar repeatability and detection limits of previous methods which required more than one injection. Each step of the procedure was optimized to produce a robust, reproducible, accurate, precise and efficient method. The required selectivity and sensitivity for trace-level analysis (e.g., limits of detection below 0.5ng/mL) was achieved using a narrow diameter analytical column, higher than unit mass resolution for certain analytes, and stable isotope labeled internal standards. The method was applied to the analysis of 55 samples collected from adult anonymous donors with no known exposure to the target pesticides. This efficient and cost-effective method is adequate to handle the large number of samples required for national biomonitoring surveys.

Semi-automated solid-phase extraction method for studying the biodegradation of ochratoxin A by human intestinal microbiota

A simple and rapid semi-automated solid-phase (SPE) extraction method has been developed for the analysis of ochratoxin A in aqueous matrices related to biodegradation experiments (namely digestive contents and faecal excreta), with a view of using this method to follow OTA biodegradation by human intestinal microbiota. Influence of extraction parameters that could affect semi-automated SPE efficiency was studied, using C18-silica as the sorbent and water as the simplest matrix, being further applied to the matrices of interest. Conditions finally retained were as follows: 5-mL aqueous samples (pH 3) containing an organic modifier (20% ACN) were applied on 100-mg cartridges. After drying (9mL of air), the cartridge was rinsed with 5-mL H2O/ACN (80:20, v/v), before eluting the compounds with 3× 1mL of MeOH/THF (10:90, v/v). Acceptable recoveries and limits of quantification could be obtained considering the complexity of the investigated matrices and the low volumes sampled; this method was also suitable for the analysis of ochratoxin B in faecal extracts. Applicability of the method is illustrated by preliminary results of ochratoxin A biodegradation studies by human intestinal microbiota under simple in vitro conditions. Interestingly, partial degradation of ochratoxin A was observed, with efficiencies ranging from 14% to 47% after 72h incubation. In addition, three phase I metabolites could be identified using high resolution mass spectrometry, namely ochratoxin α, open ochratoxin A and ochratoxin B.

Validation and application of a liquid chromatography–tandem mass spectrometric method for the determination of G-856 (Cur-61414) in human plasma using semi-automated solid phase extraction

A liquid chromatographic–tandem mass spectrometric (LC–MS/MS) method was developed and validated for the determination of G-856 in human plasma to support clinical development. The method consisted of a solid phase extraction for sample preparation and LC–MS/MS analysis in the positive ion mode using TurboIonSpray for analysis. d8-G-856 was used as the internal standard. A linear regression (weighted 1/concentration2) was used to fit calibration curves over the concentration range of 5.00–2000pg/mL for G-856. There were no significant endogenous interference components in the multiple lots of blank human plasma tested. The accuracy (%Acc) at the lower limit of quantitation (LLOQ) was 98.2% with a precision (%CV) of 5.38%. For quality control samples at 15.0, 800, and 1600pg/mL, the inter-day %CV was ≤5.03%. Inter-day %Acc ranged from 96.9 to 99.3%. G-856 was stable in human plasma for 184days at −20°C and −70°C storage. G-856 was stable in human plasma at room temperature for up to 16h and through four freeze/thaw cycles. This validated LC–MS/MS method for determination of G-856 was used to support Phase 1 clinical studies.

Analysis of 25-hydroxyvitamin D in serum using semi-automated solid phase extraction and LC/MS/MS

Analysis of 25-hydroxyvitamin D in serum using semi-automated solid phase extraction and LC/MS/MS

Development of a rapid liquid chromatography tandem mass spectrometry method for the determination of lisinopril, applicable for a bioequivalence study, employing a 96-well format solid phase extraction protocol

A rapid liquid chromatography/tandem mass spectrometry (LC/MS-MS) method was developed for the determination of lisinopril in human plasma. Lisinopril and the internal standard enalaprilat (IS) were extracted from human plasma by semi-automated solid phase extraction (SPE) using a 96-well format extraction plate. Initially, a 1:1 plasma: acetonitrile (ACN) mixture was prepared and vortexed to achieve protein precipitation. After centrifugation, an aliquot of the supernatant water/ACN solvent mixture was evaporated. The residue was dissolved in a certain volume of a reconstitution solution, which was passed through the extraction plate and the eluent was analyzed by combined reversed phase liquid chromatography tandem mass spectrometry with positive ion electrospray ionization using multiple reactions monitoring (MRM). The method was proved to be sensitive and specific for both drugs and its statistical evaluation revealed excellent linearity for the range of concentrations 2.0–200.0 ng mL −1 and very good accuracy, and inter- and intraday precisions. The proposed method enables the rapid and reliable determination of lisinopril in pharmacokinetic or bioequivalence studies after per os administration of 20 mg tablet formulations of lisinopril and it was applied in such study from our laboratory.

Quantification of the anti-leukemia drug STI571 (Gleevec™) and its metabolite (CGP 74588) in monkey plasma using a semi-automated solid phase extraction procedure and liquid chromatography-tandem mass spectrometry

Signal Transduction Inhibitor 571 (STI571, formerly known as CGP 57148B) or Gleevec™ received fast track approval by the US Food and Drug Administration (FDA) for treatment of chronic myeloid leukemia (CML). STI571 (Gleevec™) is a revolutionary and promising new oral therapy for CML, which functions at the molecular level with high specificity. The dramatic improvement in efficacy compared with existing treatments prompted an equally profound increase in the pace of development of Gleevec™. The duration from first dose in man to completion of the New Drug Application (NDA) filing was less than 3 years. In addition, recently, FDA approved Gleevec™ for the treatment of gastrointestinal stromal tumor (GIST). In order to support all toxicokinetic (TK) studies with sufficient speed to meet various target dates, a semi-automated procedure using solid phase extraction (SPE) was developed and validated. A Packard Multi-Probe I and a SPE step in a 96-well plate format were utilized. A 3M Empore octyl (C 8)-standard density 96-well plate was used for plasma sample extraction. A Sciex API 3000 triple quadrupole mass spectrometer with an atmospheric pressure chemical ionization (APCI) interface operated in positive ion mode was used for detection. Lower limits of quantification of 1.00 and 2.00 ng/ml were attained for STI571 and its metabolite, CGP 74588, respectively. The method proved to be rugged and allowed the simultaneous quantification of STI571 and CGP 74588 in monkey plasma. Herein, assay development, validation, and representative concentration–time profiles obtained from TK studies are presented.