Porous graphitic carbon chromatography/tandem mass spectrometric determination of cytarabine in mouse plasma

Analysis of human biological samples using porous graphitic carbon columns and liquid chromatography-mass spectrometry: a review

Liquid chromatography-mass spectrometry (LC-MS) has emerged as a powerful analytical technique for analyzing complex biological samples. Among various chromatographic stationary phases, porous graphitic carbon (PGC) columns have attracted significant attention due to their unique properties-such as the ability to separate both polar and non-polar compounds and their stability through all pH ranges and to high temperatures-besides the compatibility with LC-MS. This review discusses the applicability of PGC for SPE and separation in LC-MS-based analyses of human biological samples, highlighting the diverse applications of PGC-LC-MS in analyzing endogenous metabolites, pharmaceuticals, and biomarkers, such as glycans, proteins, oligosaccharides, sugar phosphates, and nucleotides. Additionally, the fundamental principles underlying PGC column chemistry and its advantages, challenges, and advances in method development are explored. This comprehensive review aims to provide researchers and practitioners with a valuable resource for understanding the capabilities and limitations of PGC columns in LC-MS-based analysis of human biological samples, thereby facilitating advancements in analytical methodologies and biomedical research.

Simultaneous analysis of heparosan oligosaccharides by isocratic liquid chromatography with charged aerosol detection/mass spectrometry

Uncovering the biological roles of heparosan oligosaccharides requires a simple and robust method for their separation and identification. We reported on systematic investigations of the retention behaviors of synthetic heparosan oligosaccharides on porous graphitic carbon (PGC) column by HPLC with charged aerosol detection. Oligosaccharides were strongly retained by PGC material in water-acetonitrile mobile phase, and eluted by trifluoroacetic acid occurring as narrow peaks. Addition of small fraction of methanol led to better selectivity of PGC to oligosaccharides than acetonitrile modifier alone, presumably, resulting from displacement of methanol to give different chemical environment at the PGC surface. Van't-Hoff plots demonstrated that retention behaviors highly depended on the column temperature and oligosaccharide moieties. By implementing the optimal MeOH content and temperature, a novel isocratic elution method was successfully developed for baseline resolution and identification of seven heparosan oligosaccharides using PGC-HPLC-CAD/MS. This approach allows for rapid analysis of heparosan oligosaccharides from various sources.

Simultaneous determination of 1-β-d-Arabinofuranosylcytosine and two metabolites, 1-β-d-Arabinofuranosyluracil and 1-β-d-Arabinofuranosylcytosine triphosphate in leukemic cell by HPLC-MS/MS and the application to cell pharmacokinetics

A specific and reliable HPLC-MS/MS method was developed and validated for the simultaneous determination of 1-β-d-Arabinofuranosylcytosine (ara-C), 1-β-d-Arabinofuranosyluracil (ara-U) and 1-β-d-Arabinofuranosylcytosine triphosphate (ara-CTP) in the leukemic cells for the first time. The analytes were separated on a C18 column (100mm×2.1mm, 1.8μm) and a triple-quadrupole mass spectrometry equipped with an electrospray ionization (ESI) source was used for detection. The ion-pairing reagent, NFPA, was added to the mobile phase to retain the analytes in the column. The cell homogenates sample was prepared by the simple protein precipitation. The calibration curves were linear over a concentration range of 3.45-3450.0ng/mL for ara-C, 1.12-1120.0ng/mL for ara-U and 4.13-4130.0ng/mL for ara-CTP. The intra-day and inter-day precision was less than 15% and the relative error (RE) were all within ±15%. The validated method was successfully applied to assess the disposition characteristics of ara-C and support cell pharmacokinetics after the patients with leukemia were intravenously infused with SDAC and HiDAC. The result of the present study would provide the valuable information for the ara-C therapy.

Rapid and sensitive liquid chromatography-tandem mass spectrometry method for determination of 1-β-d-arabinofuranosyluracil in human plasma and application to therapeutic drug monitoring in patient with leukemia

A specific and reliable HPLC-MS/MS method was developed and validated for the determination of ara-U in human plasma. The analyte was separated on a C18 column (50 mm × 2.1mm, 1.7 μm) and a triple-quadrupole mass spectrometry equipped with an electrospray ionization (ESI) source was applied for detection. The plasma sample was prepared by a simple protein precipitation pretreatment and the recovery was about 80%. The calibration curves were linear over a concentration range of 1.0-7000.0 ng/mL for ara-U. The intra-day and inter-day precision was less than 15% and the relative error (RE) was all within ± 15%. It was successfully applied to assess the disposition characteristics of ara-U and support the therapeutic drug monitoring after the patients with leukemia were infused with ara-C.

Quantification of neutral human milk oligosaccharides by graphitic carbon high-performance liquid chromatography with tandem mass spectrometry

Defining the biological roles of human milk oligosaccharides (HMOS) requires an efficient, simple, reliable, and robust analytical method for simultaneous quantification of oligosaccharide profiles from multiple samples. The HMOS fraction of milk is a complex mixture of polar, highly branched, isomeric structures that contain no intrinsic facile chromophore, making their resolution and quantification challenging. A liquid chromatography-mass spectrometry (LC-MS) method was devised to resolve and quantify 11 major neutral oligosaccharides of human milk simultaneously. Crude HMOS fractions are reduced, resolved by porous graphitic carbon high-performance liquid chromatography (HPLC) with a water/acetonitrile gradient, detected by mass spectrometric specific ion monitoring, and quantified. The HPLC separates isomers of identical molecular weights, allowing 11 peaks to be fully resolved and quantified by monitoring mass-to-charge (m/z) ratios of the deprotonated negative ions. The standard curves for each of the 11 oligosaccharides is linear from 0.078 or 0.156 to 20 μg/ml (R(2)>0.998). Precision (coefficient of variation) ranges from 1% to 9%. Accuracy is from 86% to 104%. This analytical technique provides sensitive, precise, and accurate quantification for each of the 11 milk oligosaccharides and allows measurement of differences in milk oligosaccharide patterns between individuals and at different stages of lactation.

Occurrence of cyclophosphamide and epirubicin in wastewaters by direct injection analysis-liquid chromatography-high-resolution mass spectrometry

BACKGROUND, AIM, AND SCOPE

According to the high incidence of cancer worldwide, the amount of cytostatic drugs administered to patients has increased. These compounds are excreted to wastewaters, and therefore become potential water contaminants. At this stage, very little is known on the presence and elimination of cytostatic compounds in wastewater treatment plants (WWTP). The aim of this study was to develop a liquid chromatography-high-resolution mass spectrometry (LC-Orbitrap-MS) method for the determination of cyclophosphamide and epirubicin in wastewaters. These compounds represent two outmost used cytostatic agents.

MATERIALS AND METHODS

Extraction and analytical conditions were optimized for cyclophosphamide and epirubicin in wastewater. Both solid-phase extraction using Oasis 200 mg hydrophilic-lipophilic balanced (HLB) cartridges and direct injection analysis were evaluated. Mass spectral characterization and fragmentation conditions were optimized at 50,000 resolving power (full width at half maximum, m/z 200) to obtain maximum sensitivity and identification performance. Quality parameters (recoveries, limits of detection, and repetitivity) of the methods developed were determined, and best performance was obtained with direct water analysis of the centrifuged wastewater. Finally, this method was applied to determine the presence of cyclophosphamide and epirubicin in wastewaters from a hospital effluent, an urban effluent, and influents and effluents from three WWTP.

RESULTS AND DISCUSSION

Cyclophosphamide and epirubicin were recovered after 50 mL preconcentration on solid-phase extraction 200 mg Oasis HLB cartridges (87% and 37%, respectively), and no breakthrough was observed by extracting 500 mL of water. Limits of detection were of 0.35 and 2.77 ng/L for cyclophosphamide and epirubicin, respectively. On the other hand, direct injection of water spiked at 1 μg/L provided recoveries of 107% for cyclophosphamide and 44% for epirubicin and limits of detection from 3.1 to 85 ng L(-1), respectively. The analysis of wastewaters using direct injection analysis revealed the presence of cyclophosphamide and epirubicin in WWTP influents and hospital and urban effluents at levels ranging from 5.73 to 24.8 μg L(-1).

CONCLUSIONS

The results obtained in this study demonstrate the capability of LC-Orbitrap-MS for accurate trace analysis of these very polar contaminants. This method permitted to identify cyclophosphamide and epirubicin in wastewaters and influents of WWTP, but no traces were detected in WWTP effluents. The methodology herein developed is sensitive and robust and applicable for screening of a large number of samples since no preconcentration is needed.

Analysis of anticancer drugs: a review

In the last decades, the number of patients receiving chemotherapy has considerably increased. Given the toxicity of cytotoxic agents to humans (not only for patients but also for healthcare professionals), the development of reliable analytical methods to analyse these compounds became necessary. From the discovery of new substances to patient administration, all pharmaceutical fields are concerned with the analysis of cytotoxic drugs. In this review, the use of methods to analyse cytotoxic agents in various matrices, such as pharmaceutical formulations and biological and environmental samples, is discussed. Thus, an overview of reported analytical methods for the determination of the most commonly used anticancer drugs is given.

HPLC–MS/MS method for the determination of cytarabine in human plasma

Background: Cytarabine is an anti-tumor drug that is currently under investigation for treatment in combination with other anticancer drugs for the chemotherapy of leukemia. The quantitative determination of cytarabine in plasma is challenging due to the required sensitivity, its in vitro instability and the presence of an isobaric endogenous compound, cytidine. Owing to the polarity of cytarabine, conventional chromatography cannot provide adequate separation of the analyte and the interfering compounds. A few analytical methods have been reported for the determination of cytarabine in plasma, but their sensitivity was not sufficient since most of these methods apply spectrophotometric detection. Results: In this article, an LC–MS/MS method is described for the determination of cytarabine in human plasma down to the sub ng/ml level. To prevent conversion of cytarabine by cytidine deaminase, whole blood samples were stabilized with tetrahydrouridine directly after the collection of whole blood at the clinical site. Cation-exchange SPE was employed to extract cytarabine from 50 µl human plasma. UHPLC on high strength silica T3 column (100 × 2.1 mm × 1.8 µm) was applied to achieve adequate separation of cytarabine from cytidine within a reasonable run time of 5 min. A triple quad mass spectrometer equipped with an ESI source was used for detection. Conclusion: The method was linear over the concentration ranges of 0.500–500 ng/ml. The intra- and inter-day relative standard deviation (precision) as well as the bias (accuracy) were well below 15%. In the presence of tetrahydrouridine, cytarabine was sufficiently stable under all relevant conditions. The method was successfully applied to support a clinical pharmacokinetic study with a low dose of cytarabine.

Analysis of adenosine phosphates in HepG-2 cell by a HPLC-ESI-MS system with porous graphitic carbon as stationary phase

A high performance liquid chromatography coupled with electrospray ionization/mass spectrometry method was developed for the determination of adenosine 5'-monophosphate (AMP), adenosine 5'-diphosphate (ADP), and adenosine 5'-triphosphate (ATP) in the extract of HepG-2 cells. The chromatographic conditions were optimized by using porous graphitic carbon as the stationary phase for the retention and separation of the AMP, ADP and ATP. Negative-ion mode ESI-MS in basic mobile phase was applied to improve the method sensitivity. An external calibration method with linear ranges from 0.22 to 57.80 microM for AMP, from 0.59 to 117.37 microM for ADP, and from 0.49 to 98.81 microM for ATP was used for quantitative analysis. The levels of ATP, ADP, and AMP in HepG-2 cells treated with benzo[a]pyrene with different time periods were determined. Total adenine nucleotides and the energy charge potential were calculated for the investigation of the effect of benzo[a]pyrene on cell energy metabolism.

Quantification of polar drugs in human plasma with liquid chromatography–tandem mass spectrometry

Liquid chromatography–tandem mass spectrometry (LC–MS/MS) has played an important role in quantitative bioanalytical assays. This review summarizes the recent progress on quantification of polar drugs in plasma with LC–MS/MS. Various types of polar analytes were extracted using protein precipitation or solid-phase extraction and precolumn derivatization was utilized in some cases. The analytes were then separated using different types of chromatographic method, which included reversed-phase chromatography, aqueous normal-phase chromatography, hydrophilic interaction liquid chromatography and ion-pairing chromatography. Stationary phases of mixed mode and porous graphitic carbon materials are gaining acceptance in bioanalytical applications. These technologies can be valuable supplements in the quantification of polar drugs in human plasma with LC–MS/MS. Matrix effects have also been discussed in this review.

Development of a sensitive and selective LC/MS/MS method for the simultaneous determination of intracellular 1-beta-D-arabinofuranosylcytosine triphosphate (araCTP), cytidine triphosphate (CTP) and deoxycytidine triphosphate (dCTP) in a human follicular lymphoma cell line

A method was developed for the quantification of araCTP, CTP and dCTP in a human follicular lymphoma cell line. This method involves solid phase extraction (SPE) using a weak anion-exchanger (WAX) cartridge, a porous graphitic carbon high-performance liquid chromatography (HPLC) column separation, and tandem mass spectrometry (MS/MS) detection. By using a triple quadrupole mass spectrometer operating in negative ion multiple reaction monitoring (MRM) mode, the method was able to achieve a lower limit of quantification (LLOQ) of 0.1 microg mL(-1) for araCTP and of 0.01 microg mL(-1) for both CTP and dCTP. The method was validated and used to determine the amount of araCTP, CTP and dCTP formed after incubation of araC and an araCMP prodrug in the human follicular lymphoma cell line RL.

Challenge of high polarity and low concentrations in analysis of cytostatics and metabolites in wastewater by hydrophilic interaction chromatography/tandem mass spectrometry

A method for solid phase extraction and HPLC-MS/MS of the cytostatics 5-fluorouracil, cytarabine, and gemcitabine and human metabolites uracil 1-beta-d-arabinofuranoside and 2',2'-difluorodeoxyuridine in wastewater was established. Wastewater samples from a Swiss hospital were analyzed for 5-fluorouracil, gemcitabine and 2',2'-difluorodeoxyuridine. The limits of quantification were 5.0, 0.9, and 9.0ng/L and the maximum concentrations detected were 27, 38, and 840ng/L, respectively. Along with the method development, retention mechanisms on the hydrophilic interaction chromatography (HILIC) stationary phase were studied. Both partitioning and adsorption play a role in the retention on the tested sulfoalkylbetaine modified silica HILIC column material. The contribution of these two processes is changing over the 1.6-40% range water in the mobile phase. Although the specific break point is difficult to determine, adsorption becomes more significant as the fraction of water in the mobile phase decreases below approximately 16%.