Simple Liquid Chromatography-electrospray Ionization Research Articles

A simple and robust LC-ESI single quadrupole MS-based method to analyze polyphenols in plant extracts using deep eutectic solvents

Currently, the interest in polyphenols is increasing due to their significant properties in health. Polyphenols exist in a range of natural products, however their extraction as well as their characterization are important issues as they are mainly present in complex matrices. Therefore, sensitive and selective analytical methods based on liquid chromatography coupled to tandem mass spectrometry are essential. Nevertheless, access to such high-resolution techniques is quite rare. Thus, in this work we present a simple, selective and robust method based on a single-quadrupole (Q) MS technique) for the analysis of a wide range of polyphenols such as flavonoids, phenolic acids and anthocyanins.Specifically, we present:•A simple liquid chromatography electro-spray ionization (LC-ESI) single-quadrupole mass selective (MS) method for the analysis of 18 different polyphenols.•Application of the method to three plant-based extracts that are derived after green extraction methods.

Simple liquid chromatography-electrospray ionization ion trap mass spectrometry method for the quantification of galacto-oxylipin arabidopsides in plant samples

A simple and sensitive method to quantify five different arabidopsides by HPLC—ion trap mass spectrometry in complex plant samples was developed and validated. Arabidopsides are oxidized galactolipids first described in Arabidopsis thaliana but also produced by other plant species under stress conditions. External calibration was performed using arabidopsides purified from freeze-thawed Arabidopsis leaves. Lipids were extracted and pre-purified on an SPE silica column before HPLC–MS analysis. Arabidopsides were separated on a C18 column using a gradient of mQ water and acetonitrile:mQ water (85:15) supplemented with formic acid (0.2%) and ammonium formate (12 mM). The method was validated according to European commission decision 2002/657/CE. LOD, LOQ, linearity, intra-day and inter-day precision and accuracy, selectivity, matrix effects and recoveries were determined for the five metabolites. The established method is highly selective in a complex plant matrix. LOD and LOQ were, respectively, in the range 0.098–0.78 and 0.64–1.56 µM, allowing the arabidopside quantification from 25.6–62.4 nmol/g fresh weight. Calibration curve correlation coefficients were higher than 0.997. Matrix effects ranged from -2.09% to 6.10% and recoveries between 70.7% and 109%. The method was successfully applied to complex plant matrixes: Arabidopsis thaliana and Nasturtium officinale.

Liquid Chromatography/Mass Spectrometry Method for the Simultaneous Determination of Atorvastatin and Telmisartan in Human Plasma

A simple liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed and validated for the simultaneous determination of Atorvastatin (ATO) and telmisartan (TEL) in human plasma. After liquid-liquid extraction step, the analytes and internal standard, rosuvastatin (ROS) were separated using an isocratic mobile phase consisting of 10 mM ammonium acetate (pH=4)-methanol (20:80, v/v) on a reverse-phase C18 column. Detection was carried out on mass spectrometer by using electrospray ionization (ESI) source using their respective [M+H] + ions, m/z 482 for ROS, m/z 515 for TEL, and m/z 559 for ATO. For both drugs, the method was linear in the range of 1-35 ng/mL. Acceptable precision and accuracy were obtained for concentrations in the calibration range.

A simple and robust LC-ESI single quadrupole MS-based method to analyze neonicotinoids in honey bee extracts

Over the past years, neonicotinoids such as thiacloprid and flupyradifurone have gained considerable scientific and public interest. These molecules used as active compounds in pesticides are known due to cause drastic negative long-time effects on pollinators and even human health. Therefore, determining trace amounts of neonicotinoid in different environmental matrices by liquid chromatography coupled with mass selective detectors (LCMS/MS or LC-Q-TOF/MS) has become an important methodology. However, not every scientific group has unlimited access to high-resolution mass-selective detectors (e.g., MS/MS). It becomes more apparent that the analytics of neonicotinoids are already a global issue. Research groups and organizations with a limited financial budget often depend on using cheap and robust equipment to do their analytical work. We demonstrate a single-quadrupole (Q) MS-based method with single-class residue methods (SRMs) for the analysis of neonicotinoids, applicable without the requirement of a high-end MS system. For an adequate sample clean-up strategy, QuEChERS (Quick, Easy, Cheap, Efficient, Rugged, safe) extraction and purification methods were modified and applied to eliminate residual matrix after honey bee extraction steps to analyze thiacloprid and flupyradifurone.•Simple liquid chromatography electro-spray ionization (LC-ESI) single-quadrupole mass selective (MS) method for neonicotinoid analysis.•Efficient sample pretreatment by a modified QuEChERS extraction and purification method.•Limit of detection (LOD) and limit of quantification (LOQ) for thiacloprid was 19.72 ng g−1 and 7.61 ng g−1, for flupyradifurone 65.73 ng g−1 and 25.36 ng g−1, respectively.

In vitro permeability, pharmacokinetics and brain uptake of WAY-100635 and FCWAY in rats using liquid chromatography electrospray ionization tandem mass spectrometry

Positron emission tomography (PET) is a sensitive non-invasive imaging technique. To reduce imaging measurements of defects, there is a demand for proper LC-ESI-MS/MS method to carry out with its specificity and sensitivity. This study describes a rapid and simple liquid chromatography electrospray ionization tandem-MS/MS (LC-ESI-MS/MS) method for determination of both PET tracers: N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridyl)cyclohexanecarboxamide (WAY-100635) and 4-fluoro-N-[2-[4-(2-methoxylphenyl)-1-piperazino]ethyl]-N-(2-pyridyl)cyclohexanecarboxamide (FCWAY). Both target compounds were prepared by one-step protein precipitation with acetonitrile and methanol (1:1, v/v), and analyzed using a C18 column. This simple method has an excellent linearity, selectivity and sensitivity. Precision and accuracy values for the intra-day and inter-day validation were below 12%. The limit of quantification (LOQ) for both target compounds was defined as 1 ng/mL in plasma and 5 ng/mL in brain homogenate. The stability of both compounds is considered stable under a various experimental conditions. The in vitro MDR-MDCK cell permeability showed the both compounds have high permeability (Papp, A→B ≥ 20 × 10(-6 )cm/s) and low efflux ratio (≤2.0). Brain to blood (AUCbrain/AUCblood) distribution ratios in rats were 3.15 ± 0.42 for WAY-100635 and 2.20 ± 0.34 for FCWAY, respectively, and these results suggest that LC-ESI-MS/MS method might be a supplementary way for the identifying and understanding of radiopharmaceuticals.

Development and validation of automated SPE‐LC‐MS/MS method for determination of indapamide in human whole blood and its application to real study samples

A fast and simple liquid chromatography-electrospray ionization tandem mass spectrometry method for determination of indapamide in human whole blood was developed and validated. The sample extraction of indapamide from human whole blood was achieved using automated solid-phase extraction. Chromatographic separation was performed on Kinetex C18 column (100 × 2.1 mm, 1.7 µm particle size) using acetonitrile and 2 mm ammonium formate in ratio 90:10 (v/v) as a mobile phase. The mass spectrometer was operated in the multiple reaction monitoring mode using positive electrospray ionization for indapamide and the internal standard (zolpidem tartarate). The total run time was 2.5 min. The present method was found to be linear in the concentration range of 1-50 ng/mL with the coefficient of determination 0.9987. The absolute recoveries of indapamide were 90.51-93.90%. The method was validated according the recommendations for validation of bioanalytical methods of European Medicines Agency guideline and was successfully used to analyze human whole blood samples for application in a pharmacokinetic study.

Determination of cyclobenzaprine in human plasma by liquid chromatography‐electrospray ionization tandem mass spectrometry and its application in a pharmacokinetic study

A sensitive, rapid and simple liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS/MS) method was developed for the quantitative determination of cyclobenzaprine in human plasma, to study the pharmacokinetic behavior of cyclobenzaprine capsule in healthy Chinese volunteers. With escitalopram as the internal standard (IS), sample pretreatment involved a one-step liquid-liquid extraction using saturated sodium carbonate solution and hexane-diethyl ether (3:1, v/v). The separation was performed on an Ultimate XB-CN column (150 × 2.1 mm, 5 µm). Isocratic elution was applied using acetonitrile-water (40:60, v/v) containing 10 m M ammonium acetate and 0.1% formic acid. The detection was carried out on a triple-quadrupole tandem mass spectrometer in multiple reaction monitoring mode via electrospray ionization. The ion-pairs including m/z 276.2-216.2 for cyclobenzaprine and m/z 325.2-109.1 for IS were used for monitoring. Linear calibration curves were obtained over the range of 0.049-29.81 ng/mL with the lower limit of quantification at 0.049 ng/mL. The intra- and inter-day precision showed ≤ 6.5% relative standard deviation. The established method laid the groundwork for follow-up studies and provided basis for the clinical administration of cyclobenzaprine.

Quantitative determination of helicid in rat biosamples by liquid chromatography electrospray ionization mass spectrometry

A simple liquid chromatography electrospray ionization mass spectrometry (LC–ESI–MS) method with highly improved sensitivities for the determination of helicid in rat bile, urine, feces and most tissues was developed. The tissues and feces were firstly homogenized mechanically using deionized water as the media. Bile, urine, tissues and feces homogenates were extracted by liquid–liquid extraction with n-butyl alcohol for sample preparation. The subsequent analysis procedures were performed on a Shimadzu LCMS2010A system (electrospray ionization single quadrupole mass analyzer). A Luna C 18 column (150 mm × 2.00 mm, 5 μm) was used as the analytical column, while a mixture of acetonitrile and ammonium chloride water solution was used as the mobile phase. The proportions of mobile phase were changed timely according to gradient programs. Chlorinated adducts of molecular ions [M+Cl] − at m/ z 319.00 and 363.05 were used to quantify helicid and bergeninum (internal standard), respectively. The method was validated to be accurate, precise and rugged with good linearity. The proposed method was successfully applied to the preclinical tissue distribution and excretion studies of helicid in rats.

Hair analysis of nicotine and cotinine for evaluating tobacco smoke exposure by liquid chromatography-mass spectrometry.

A simple liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method for the determination of nicotine and cotinine in human hair was established. In the procedure, a hair sample (10 mg) was washed with dichloromethane and digested in 2.5 M sodium hydroxide. The digest was extracted with dichloromethane and then 25 mM hydrochloric acid in methanol was added to the extract, to prevent loss of analytes. The solution was evaporated and redissolved in the mobile phase, methanol/10 mM ammonium acetate (30/70, v/v). A 20 microL aliquot of redissolved solution was subjected to analysis. Nicotine and cotinine in human hair were quantified by using deuterated analytes as internal standards. The quantification limits were 8 microg/L for nicotine and 0.9 microg/L for cotinine. The proposed method was applied to measure the concentrations of nicotine and cotinine in hair of smokers and non-smokers to evaluate their self-reported smoking and exposure to environmental tobacco smoke. In both cases, the method provided good selectivity, accuracy and precision.