Christoph Seger

• PD Dr.
• Independant Researcher at University of Innsbruck

Covering: 2005 to 2013Current natural product research is unthinkable without the use of high resolution separation techniques as high performance liquid chromatography or capillary electrophoresis (HPLC or CE respectively) combined with mass spectrometers (MS) or nuclear magnetic resonance (NMR) spectrometers. These hyphenated instrumental analysi...

Monitoring immunosuppressive drugs (ISDs) in blood or plasma is still a key therapeutic drug monitoring (TDM) application in clinical settings. Narrow target ranges and severe side effects at drug underexposure or overexposure make accurate and precise measurements a must. This overview prepared by the Immunosuppressive Drugs Scientific Committee o...

Thanks to highly specific analyte detection and potentially complete compensation for matrix variables based on the principle of stable isotope derivative internal standardisation, mass spectrometry methods allow the development of diagnostic tests of outstanding analytical quality. However, these features per se do not guarantee reliability of tes...

Ten years ago, a consensus report on the optimization of tacrolimus was published in this journal. In 2017, the Immunosuppressive Drugs Scientific Committee of the International Association of Therapeutic Drug Monitoring and Clinical Toxicity (IATDMCT) decided to issue an updated consensus report considering the most relevant advances in tacrolimus...

Tandem mass spectrometry – especially in combination with liquid chromatography (LC-MS/MS) – is applied in a multitude of important diagnostic niches of laboratory medicine. It is unquestioned in its routine use and is often unreplaceable by alternative technologies. This overview illustrates the development in the past decade (2009-2019) and inten...

The Immunosuppressive Drugs Scientific Committee of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology established the second consensus report to guide Therapeutic Drug Monitoring (TDM) of everolimus (EVR) and its optimal use in clinical practice 7 years after the first version was published in 2016. This version p...

Objectives Primidone is an anticonvulsive drug used in the treatment of epilepsy and essential tremor. It offers beneficial effects in controlling seizures, but its usage is also associated with possible side effects. To ensure optimal therapy, it is crucial to measure its concentration through accurate quantification methods. Therefore, our main g...

Objectives Phenobarbital serves as an antiepileptic drug (AED) and finds application in the treatment of epilepsy either as monotherapy or adjunctive therapy. This drug exhibits various pharmacodynamic properties that account for its beneficial effects as well as potential side effects. Accurate measurement of its concentration is critical for opti...

Objectives To describe and validate an isotope dilution-liquid chromatograph-tandem mass spectrometry (ID-LC-MS/MS) based reference measurement procedure (RMP) for zonisamide to accurately measure serum and plasma concentrations. Methods Quantitative nuclear magnetic resonance (qNMR) spectroscopy was employed to determine the absolute content of t...

Objectives An isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS)-based candidate reference measurement procedure (RMP) was developed and validated to accurately measure serum and plasma concentrations of carbamazepine. Methods Quantitative nuclear magnetic resonance (qNMR) spectroscopy was used to determine the absolute...

Objectives: Topiramate is an antiepileptic drug (AED) used for the monotherapy or adjunctive treatment of epilepsy and for the prophylaxis of migraine. It has several pharmacodynamic properties that contribute to both its clinically useful properties and observed adverse effects. Accurate measurement of its concentration is therefore essential for...

Objectives: To develop an isotope dilution-liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based candidate reference measurement procedure (RMP) for levetiracetam quantification in human serum and plasma. Methods: Quantitative nuclear magnetic resonance spectroscopy (qNMR) was used to characterize the RMP material to ensure traceabilit...

Objectives: We developed an isotope dilution (ID)-liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based candidate reference measurement procedure (RMP) for lamotrigine in human serum and plasma, using quantitative nuclear magnetic resonance-characterized reference standards to ensure traceability to the International System of Units. Me...

Objectives To describe and validate a reference measurement procedure (RMP) for gabapentin, employing quantitative nuclear magnetic resonance (qNMR) spectroscopy to determine the absolute content of the standard materials in combination with isotope dilution-liquid chromatograph-tandem mass spectrometry (ID-LC-MS/MS) to accurately measure serum and...

For molecules that can be well described metrologically in the sense of the definition of measurands, and which can also be recorded analytically as individual substances, reference measurement service traceability to a metrologically sound foundation is a necessity. The establishment of traceability chains must be initiated by National Metrology I...

Gaining structural information is a must to allow the unequivocal structural characterization of analytes from natural sources. In liquid state, NMR spectroscopy is almost the only possible alternative to HPLC-MS and hyphenating the effluent of an analyte separation device to the probe head of an NMR spectrometer has therefore been pursued for more...

This study presents the first ultra-high performance supercritical fluid chromatography-diode array detector (UHPSFC-DAD) assay for simultaneous quantitation of secoiridoids, iridoids, xanthones, and xanthone glycosides in Gentiana lutea L. Separation was reached within 12 min on an Acquity UPC2 BEH 2-EP column using CO2 and methanol with 5.5% wate...

By combining HPLC-DAD-QTOF-MS and HPLC-SPE-NMR, the in vitro metabolism of vitetrifolin D, a pharmacologically active key molecule from Vitex agnus-castus in liver cell fractions, was investigated. Twenty-seven phase I and phase II metabolites were tentatively identified from the culture broth by HPLC-DAD-QTOF-MS. The subsequent HPLC-SPE-NMR analys...

When mycophenolic acid (MPA) was originally marketed for immunosuppressive therapy, fixed doses were recommended by the manufacturer. Awareness of the potential for a more personalized dosing has led to development of methods to estimate MPA area under the curve based on the measurement of drug concentrations in only a few samples. This approach is...

Although SARS-CoV-2 antibody assays have been found to provide valid results in EDTA-anticoagulated whole blood, so far, they have not demonstrated that antibody levels in whole blood originating from capillary blood samples are comparable to antibody levels measured in blood from a venous origin. Here, blood is drawn simultaneously by capillary an...

Background: A combined indicator for the determination of vitamin B12 status (4cB12) that employs four markers of vitamin B12 status (i.e., holotranscobalamin, HoloTC; vitamin B12, B12; methyl malonic acid, MMA; and homocysteine, Hcy) has been proposed for the comprehensive assessment of B12 status. We aimed to compare recently published 2- (2cB12...

A 23 year old man and his grandmother with hyperthyroxinemia and hypercortisolemia were heterozygous for an ALB mutation (p. Arg218Pro), known to cause Familial Dysalbuminemic Hyperthyroxinemia (FDH). However, serum free cortisol levels in these individuals were normal and total cortisol concentrations fell markedly following depletion of albumin f...

An isotope dilution LC-MS/MS based candidate reference measurement procedure for the quantification of cyclosporine A, tacrolimus, sirolimus and everolimus in human whole blood is presented to be used for evaluation and standardization of routine assays applied for therapeutic drug monitoring. The assay allows baseline separation of the four immuno...

Purpose: To investigate the effects of various progestins in combined oral contraceptives (COCs) on lamotrigine (LTG) serum concentrations and, vice versa, the potential impact of LTG on progestin serum levels during the menstrual cycle. Methods: Twenty women with epilepsy (WWE) undergoing LTG monotherapy and COC (LTG group; mean ± SD [median; r...

This report presents the first ultra high performance supercritical fluid chromatography diode array detector based assay for simultaneous determination of iridoid glucosides, flavonoid glucuronides, and phenylpropanoid glycosides in Verbena officinalis (Verbenaceae) extracts. Separation of the key metabolites was achieved in less than 7 min on an...

Die Lebenserwartung bei Geburt für Personen, die 1969 geboren sind, liegt in der Schweiz rund zehn Jahre tiefer als für jene, die 2019 geboren wurden. Mit dem Ansteigen der Lebenserwartung steigt unter anderem auch die Anzahl an älteren Patienten, die ambulante oder stationäre medizinische Versorgung benötigen. Entsprechend nimmt die Bewertung von...

Correction for ‘The value of universally available raw NMR data for transparency, reproducibility, and integrity in natural product research’ by James B. McAlpine et al. , Nat. Prod. Rep. , 2018, DOI: 10.1039/c7np00064b.

Covering: up to 2018 With contributions from the global natural product (NP) research community, and continuing the Raw Data Initiative, this review collects a comprehensive demonstration of the immense scientific value of disseminating raw nuclear magnetic resonance (NMR) data, independently of, and in parallel with, classical publishing outlets....

No data are available on the in vivo impact of infections with in vitro azole-resistant Aspergillus fumigatus in immunocompetent hosts. Here, the aim was to investigate fungal fitness and treatment response in immunocompetent mice infected with A. fumigatus (parental strain [ps]) and isogenic mutants carrying either the mutation M220K or G54W (cyp5...

Metabolomics is a well-established field in fundamental clinical research with applications in different human body fluids. However, metabolomic investigations in feces are currently an emerging field. Fecal sample preparation is a demanding task due to high complexity and heterogeneity of the matrix. To gain access to the information enclosed in h...

A validated LC-MS/MS-based candidate reference measurement procedure for the quantification of carbamazepine is presented in order to be used for standardization and harmonization of routine assays applied for therapeutic drug monitoring. Sample preparation was based on protein precipitation using acetonitrile followed by sample dilution. Since the...

Background In laboratory medicine, routine periodic analyses for internal and external quality control measurements interpreted by statistical methods are mandatory for batch clearance. Data analysis of these process-oriented measurements allows for insight into random analytical variation and systematic calibration bias over time. However, in such...

A QuEChERS-based extraction protocol combined with a fast and selective UHPLC-QTOF-MS assay for the detection and quantification of destruxins from honey is described. The internal standard fortified assay showed satisfying assay precision and accuracy and allowed quantification of destruxin A and B down to ppb range with limits of detection (LOD)...

In 2014, the Immunosuppressive Drugs Scientific Committee of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology called a meeting of international experts to provide recommendations to guide therapeutic drug monitoring (TDM) of everolimus (EVR) and its optimal use in clinical practice. EVR is a potent inhibitor of t...

Quantitative NMR spectroscopy (qNMR) is known as excellent alternative to chromatography based mixture analysis. NMR spectroscopy is a non-destructive method, needs only limited sample preparation and can be readily automated. A head-to-head comparison of qNMR to an uHPLC-DAD based quantitative analysis of six flavonolignan congeners (silychristin,...

Introduction: A circadian variation of the endogenous coagulation system exists with hyper-coagulability and hypofibrinolysis and a corresponding peak of cardiovascular thromboembolic events in the morning. So far, no information is given, whether single daily doses of the new oral anticoagulant drug rivaroxaban should best be administered in the...

Silybum marianum (L.) Gaertn. (Asteraceae) is one of the most investigated plant extracts with known mechanism of action. Milk thistle preparations have been used to treat a variety of ailments, particularly against liver damage. The beneficial properties of S. marianum are ascribed to silymarin, a mixture of (at least) six flavonolignans and one f...

A fast and selective ultrahigh-performance supercritical fluid chromatography photodiode array detector method was established for the qualitative and quantitative analysis of destruxins, cyclic hexadepsipeptides, from fungal culture broth samples. Prior to analysis, sample purification was carried out using an off-line solid-phase extraction proto...

Elevated Carbohydrate-deficient transferrin (CDT) levels are used as a biomarker in order to screen for chronic alcohol abuse. Transferrin (Tf) variants can impair methods to measure elevated CDT levels such as high-performance liquid chromatography (HPLC). We present a Tf variant affecting the second glycosylation site of Tf and the complications...

Monitoring of anti-coagulation with the direct factor Xa inhibitor rivaroxaban is considered unnecessary in a routine clinical setting. However, assessment of its anti-coagulant effect may be desirable in certain clinical situations. We assessed prothrombin time (PT) reagents and commercially available anti-Xa assays (Biophen) calibrated for rivaro...

The entomopathogenic fungus Metarhizium brunneum is widely applied as biological pest control agent. Consequently its use has to be accompanied by a risk management approach, which includes the need to monitor the fate of its bioactive metabolites in the environment, e.g. in treated crops. A fast and selective UHPLC-QTOF-MS method was developed to...

Breath tests allow a non-invasive and fast diagnostic of different specific enzymes’ phenotypic functionality. Over the last decade several ¹³C-breath tests were successfully tested, with the ¹³C-urea breath test being approved by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA). The use of other targets than labele...

A fast and selective ultrahigh-performance liquid chromatography diode array detector (UHPLC-DAD) method combined with an off-line solid phase extraction (SPE) protocol was established to monitor destruxins (dtxs), a secondary metabolite class of highly bioactive cyclic depsipeptides. Sample purification via SPE was tailored to remove both more pol...

This chapter provides basic guidance to understand nuclear magnetic resonance (NMR) spectroscopy in the context of natural product analysis. It is intended to provide the reader an introduction to the field and also to the following chapters of this handbook. The most important 1D- and 2D-NMR experiments are described; pitfalls of the structure elu...

Background: Nodding syndrome (NS) is a seemingly progressive epilepsy disorder of unknown underlying cause. We investigated association of pyridoxal-phosphate serum levels and occurrence of anti-neuronal antibodies against N-methyl-D-aspartate (NMDA) receptor and voltage gated potassium channel (VGKC) complex in NS patients. Methods: Sera of a T...

Introduction Tyrosine kinase inhibitor (TKI) trough plasma level testing and pharmacodynamic evaluation (i.e. quantification of phosphorylated BCR-ABL downstream targets) may help to optimize patient-tailored dosing in CML-CP. For 2nd generation TKIs the clinical value of TKI plasma level and protein phosphorylation quantification remains unclear....

Within a few years, 25-hydroxyvitamin D (25-OHD) 1 has emerged as a high volume test in many regions. Several analytical issues have been recognized regarding this analyte, in particular variable co-detection of metabolites (25-hydroxyvitamin D 2; 3-epi-25-hydroxyvitamin D; 24,25-dihydroxyvitamin D), variable release of the analyte from its protein...

Qualitativ hochwertige Diagnostik spielt für die Überwachung des Therapieerfolgs bei Patienten mit chronisch myeloischer Leukämie eine entscheidende Rolle. Die Verfügbarkeit neuer Tyrosinkinase-Inhibitoren, die zu einem rascheren und tieferen Therapieansprechen führen, erfordert den Einsatz standardisierter und hochsensitiver Diagnostikmethoden, um...

Caspofungin pharmacokinetics was assessed in 27 critically ill patients, including 7 on continuous venovenous hemofiltration (CVVH), 8 on continuous venovenous hemodialysis (CVVHD), and 13 not requiring continuous renal replacement therapy (CRRT). Caspofungin exposure during CRRT was very similar to that of the control group and comparable to that...

Kv1.3-channels are critically involved in activation and function of effector memory T cells. Blocking Kv1.3-channels was investigated for its effect on skin rejection in a rat limb-transplantation-model. Animals received the Kv1.3-blocker correolide C systemically or locally as intra-graft-treatment in combination with tacrolimus. Systemic (intrap...

A rapid ultra-high performance liquid chromatography diode array detector (UHPLC-DAD) method was developed and validated for the simultaneous determination of all classes of non-volatile phytochemicals (iridoids, flavonoids and diterpenes) in Vitex agnus-castus (Lamiaceae) fruits, a traditional medicinal plant used against premenstrual symptoms (PM...

Technical maturation of liquid chromato-graphy tandem mass spectrometry (LC-MS/MS) brought this technology into most tertiary care clinical laboratories worldwide. It extended the technological armamentarium of clinical laboratories significantly, both in analytical and economical terms. Especially in therapeutic drug monitoring, endocrinology, and...

The technical maturation of liquid chromatography tandem mass ­spectrometry (LC-MS/MS) hyphenations brought this technology into most of the major clinical laboratories worldwide. It found its sound place amongst major basic routine technologies of laboratory medicine as enzyme based assays or immunoassays. LC-MS/MS extended the technological armam...

During recent years, it has been recognized that sub-optimum vitamin D-status, often defined as decrease of PTH concentrations in response to supplementation of vitamin D, is a very widespread finding with potential health effects on a population level. As a consequence, there is a continuously increasing interest in the laboratory-based assessment...

Combining the most powerful separation techniques, i.e. liquid chromatography (LC) or capillary electrophoresis (CE) with a information rich detection system - the mass spectrometer or the nuclear magnetic resonance (NMR) spectrometer - has been pursued for more than three decades. This compilation shall provide an overview of the advantages and li...

The characterization of T. vulgaris plant material for quality control purposes was performed by NMR-based methods. Direct extraction of 141 T. vulgaris samples with DMSO-d 6 enabled the obtainment of crude extracts with a representative composition in terms of both volatile and non-volatile constituents. The acquisition of 600 MHz 1H NMR spectra r...

The levonorgestrel-releasing intrauterine system (LNG-IUS) is well accepted as an easy-to-use contraceptive with an excellent side-effect profile. It contains a reservoir of 52 mg of levonorgestrel (LNG) with continuous release of the steroid. Its contraceptive use is approved for 5 years. The aim of this study was to determine the plasma concentra...

Co-administration of synthetic progestin containing hormonal contraceptives (HCs) and antiepileptic drugs (AEDs) is a common clinical situation which needs specific considerations due to drug interactions. Several studies have demonstrated that lamotrigine plasma levels are significantly decreased during co-medication with HCs, and that this intera...

Introduction The levonorgestrel-releasing intrauterine system IUS (Mirena®) is well accepted as an easy to use contraceptive with an excellent side effect profile. It contains a reservoir of 52 mg levonorgestrel (LNG) with continuous release of the steroid. Its contraceptive use is approved for five years. The aim of this study was to determine the...

Teicoplanin (TP) pharmacokinetics was assessed in a critically ill patient during albumin dialysis (AD), which was performed with the molecular adsorbent recirculating system. After a 1200-mg loading dose (24 mg/kg), doses of 1200 and 1000 mg (20 mg/kg) on day 2 and 3, respectively, were administered during two cycles of AD. The mean TP peak and tr...

Die Tandem-Massenspektrometrie und ihre Kopplung zur Flüssigchromatographie (LC-MS/MS) haben sich in den letzten zehn Jahren von einem Forschungsinstrumentarium zu einer erfolgreichen und gut etablierten Routinemethode in der klinischen Chemie und Laboratoriumsdiagnostik entwickelt.

A selective and sensitive liquid chromatography-tandem mass spectrometry method for the determination of very low levonorgestrel (D-(-)-norgestrel) serum levels such as those found in patients using levonorgestrel-releasing intrauterine devices (IUDs) was developed. To achieve the sub-nanomolar sensitivity needed to measure such serum levels, a die...

The objective of this case-control study of 242 reproductive-age women was to determine the concentration of afamin in the serum and peritoneal fluid of women with and without endometriosis and to test afamin as a diagnostic marker of endometriosis. Afamin levels were altered significantly in the peritoneal fluid of women with endometriosis compare...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Conventional chromatographic methods for the characterization of Thymus vulgaris raw plant material comprise a combination of GC and LC, respectively employed for the analysis of monoterpenoids and phenolic constituents. Herein we demonstrate the suitability of 1H NMR-based metabolic profiling for the quality control of T. vulgaris aerial parts of...

Novel mass spectrometric techniques such as atmospheric pressure ionization and tandem mass spectrometry have substantially extended the spectrum of clinical chemistry methods during the past decade. In particular, liquid chromatography tandem-mass spectrometry (LC-MS/MS) has become a standard tool in research laboratories as well as in many clinic...

The quantitative assessment of immunosuppressant drug levels is still one of the most challenging therapeutic drug monitoring procedures in clinical routine. During the past years, several technical developments matured to useable methods. In addition to immunoassays, liquid chromatography- tandem mass spectrometry has become a key method in immuno...

A new quinazolone derivative, (Z)-3,4-dihydro-3-(2-phenyIethcnyl)-quinazolin-4-one was isolated from Glycosmis cf. chlorosperma SPRENG. (Rutaceae). The structure was elucidated on the basis of spectroscopic data and confirmed by comparison with synthetically obtained material. The compound showed bioactivity against different test organisms.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Zusammenfassung Die Erfassung von Immunsuppressivaspiegel ist eine der anspruchsvollsten Medikamentenspiegelmessungen in der klinischen Routine. Die vergangenen Jahre haben eine Reihe von technologischen Fortschritten gebracht. Neben neuen immunologischen Analysesystemen hat sich die LC-MS/MS zu einem fixen Bestandteil des Geschehens entwickelt. De...

Pharmacokinetics of teicoplanin (TP) was assessed in critically ill patients on continuous veno-venous hemofiltration (CVVH), in eleven patients, after the first dose and in another four after repeated administration. The TP peak concentration amounted to 55.44 +/- 15.90 microg/ml and 81.28 +/- 28.55 microg/ml (mean +/- SD), the trough concentratio...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

NMR based metabolic profiling techniques are rapidly emerging as promising tools for the quality control of medicinal plants and plant derived products [1]. However, their use is often limited by sample complexity, which makes the identification of discriminating constituents a challenging task [2]. The use of hyphenated techniques such as LC-SPE-N...

Fifteen prenylated or geranylated flavanones and flavanonols were isolated from the leaf extracts of different Glycosmis species collected in Thailand and Malaysia. All structures were elucidated by spectroscopic methods, especially 1D and 2D NMR. Six compounds were described for the first time and two were only known so far as synthetic products....

A series of mifepristone derivatives with different "linker groups" in position 4' of the phenyl ring in the 11beta-position of the steroid scaffold (2-41) have been synthesized. Their antigestagenic activites were determined in a cell-based assay (alkali phosphatase assay in T47-D breast cancer cells) and compared with that of the parent compound...

Despite the lower patency of venous compared with arterial coronary artery bypass grafts, approximately 50% of grafts used are saphenous vein conduits because of their easier accessibility. In a search for ways to increase venous graft patency, we applied the results of a previous pharmacological study screening for non-toxic compounds that inhibit...

In the past few years, high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) has matured to a true alternative to antibody-based immunoassays in routine therapeutic drug monitoring. In transplantation medicine, mass spectrometry-based assessment of immunosuppressant drug levels is considered a gold standard diagnostic procedu...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Thymus vulgaris L. represents one of the major ingredients of herbal medicinal products used for the treatment of bronchitis and cough. Authenticity, yield of desired secondary metabolites, possible adulteration or spoilage of the starting drug material are quality control issues which have to be investigated. NMR based metabolic profiling techniqu...

During the past decade, tandem mass spectrometry hyphenated to liquid chromatography separation systems (HPLC-MS/MS) has developed to an important technology in clinical chemistry - not only for research purposes but also for routine use. At present, most important application fields are target analyses in therapeutic drug monitoring (TDM) and meta...

A new series of 20,24-epoxy (tetrahydrofuryl) type dammarane triterpenoids were established. So far two series were described, based on the stereochemistries of the tetrahydrofurane ring linked to the D ring of the triterpenoid skeleton. Eichlerianic acid was characterised by the absolute configuration (20S,24S) and shoreic acid by (20S,24R). Foveo...

The immunosuppressive mammalian target of rapamycin inhibitor rapamycin is widely used in solid-organ transplantation, but the effect of rapamycin on kidney disease is controversial. This study evaluated the effect of rapamycin in the autologous phase of anti-glomerular basement membrane (anti-GBM) glomerulonephritis. Disease was induced by preimmu...

High performance liquid chromatography-solid phase extraction-nuclear magnetic resonance (HPLC-SPE-NMR) is a novel hyphenation technology that concentrates single chromatographic peaks to elution volumes matching those of NMR flow probes. The SPE unit facilitates the solvent exchange from the mobile phase of the optimized HPLC assay to a deuterated...

Identification of putative biomarker molecules within the genus Corydalis (Papaveraceae) was pursued by combining conventional off-line sample enrichment with high-performance liquid chromatography-solid phase extraction-nuclear magnetic resonance (HPLC-SPE-NMR) based structure elucidation. Off-line reversed phase solid phase extraction (SPE) was u...

In the presented study, Central European Corydalis species, namely C. cava, C. intermedia, C. pumila, and C. solida were investigated by nonaqueous capillary electrophoresis-electrospray ion trap mass spectrometry (NACE-ESI-MS) utilizing an electrolyte consisting of 50 mM ammonium acetate, 1 M acetic acid and 10% methanol in acetonitrile, applying...