Development Of Liquid Chromatography-mass Spectrometry Research Articles

Development of Liquid Chromatography-Mass Spectrometry (LC-MS) Method for Quantification of Broccoli Sulforaphane

Sulforaphane (SFN) is an isothiocyanate and the product of the hydrolysis of glucoraphanin (GRA) by myrosinase. Broccoli is one of the rich sources of GRA and thus SFN. SFN possess a wide range of bioactivities and is considered an anti-cancer phytochemical. Most of the current common methods used to quantify SFN are based on high-pressure liquid chromatography (HPLC) with diode array detection (DAD) — also known as HPLC-DAD. Although this technique has shown encouraging results, the detection of SFN by DAD is relatively weak and affected by high interference of sample matrices. Therefore, the aim of this study was to develop a liquid chromatography-mass spectrometry (LC-MS) method in which SFN is identified by molecular mass to give more accurate results. The developed method demonstrated a highly reproducible retention time (7.204 ± 0.008 min), producing a sharp, symmetrical and well-defined sulforaphane peak in standard and test samples. The most dominant ion of sulforaphane in the pure and test samples was 178 m/z ([M + H]+). In terms of linearity, the calibration curve had a coefficient of determination (R2) of 0.9963. The limit of detection of this method is 1.3 ng/mL, and the limit of quantification is 3.9 ng/mL, indicating high sensitivity. The uniformity of peak shape and retention time in both pure and test samples were the same suggesting excellent selectivity. Overall, the developed method showed promising results in identifying and quantifying broccoli SFN.

Comprehensive peptide marker identification for the detection of multiple nut allergens using a non-targeted LC-HRMS multi-method.

Food allergies have emerged as a global problem over the last few decades; therefore, reliable and sensitive analytical methods to ensure food safety for allergic consumers are required. The application of mass spectrometry is of growing interest in this field and several procedures based on low resolution tandem mass spectrometry using single tryptic peptides as analytical targets have recently been described. However, a comprehensive survey of marker peptides for the development of multi-methods is still missing, as is a consensus guide to marker identification. In this study, we therefore report a consistent approach to the development of liquid chromatography-mass spectrometry (LC-MS) multi-screening methods for the detection of allergens in food matrices. Proteotypic peptides were identified by a shotgun proteomics approach and verified through a thorough investigation of specificity and sensitivity. On the basis of this procedure, we identified 44 suitable tryptic marker peptides from six allergenic nut species and developed the first analytical LC-MS method for the detection of trace nut contaminations in processed foods using high resolution mass spectrometry (HRMS). The analysis of spiked matrix samples gave limits of detection (LODs) below 10 μg/g for several nuts; these LODs are comparable with routinely used methods such as ELISA and PCR. Notably, the HRMS approach can be used in an untargeted fashion to identify multiple allergens also retrospectively. In conclusion, we present here the so far largest consensus set of analytical markers from nut allergens and to the best of our knowledge the first multi-allergen method based on LC-HRMS.

Multi-Mycotoxin Screening Reveals the Occurrence of 139 Different Secondary Metabolites in Feed and Feed Ingredients

The development of liquid chromatography-mass spectrometry (LC-MS)/mass spectrometry (MS) methods for the simultaneous detection and quantification of a broad spectrum of mycotoxins has facilitated the screening of a larger number of samples for contamination with a wide array of less well-known “emerging” mycotoxins and other metabolites. In this study, 83 samples of feed and feed raw materials were analysed. All of them were found to contain seven to 69 metabolites. The total number of detected metabolites amounts to 139. Fusarium mycotoxins were most common, but a number of Alternaria toxins also occurred very often. Furthermore, two so-called masked mycotoxins (i.e., mycotoxin conjugates), namely deoxynivalenol-3-glucoside (75% positives) and zearalenone-4-sulfate (49% positives), were frequently detected. Although the observed median concentrations of the individual analytes were generally in the low μg/kg range, evaluating the toxicological potential of a given sample is difficult. Toxicity data on less well-known mycotoxins and other detected metabolites are notoriously scarce, as an overview on the available information on the most commonly detected metabolites shows. Besides, the possible synergistic effects of co-occurring substances have to be considered.

The determination of N-nitrosamines in food

Introduction N-nitrosamines are formed in food as a result of natural chemical interactions, but mainly through food processing activity. Most are potent carcinogens and their determination is therefore of considerable importance. They exist in various chemical forms and have been measured by colorimetric and spectroscopic methods following gas or liquid chromatography or as a total N-nitroso group by measurement of chemically released nitric oxide. Objectives To provide an overview of the available methods for the analysis of N-nitrosamines in food that includes recently developments. Methods The literature was reviewed from the discovery of the N-nitrosamine problem and the introduction on the N-nitroso-specific detector. Results The evaluation shows that analytical detection methods for volatile N-nitrosamines in food have changed little since the introduction on the N-nitroso-specific detector and that research into the occurrence and formation of both non-volatile N-nitrosamines and the apparent total N-nitroso content (ATNC) have declined. Methods for measuring the apparent total N-nitroso content have not been improved significantly in recent years. Conclusion Modern sample extraction techniques and mass spectrometric methods for the volatile N-nitrosamines have been applied more extensively to water analysis and offer a good opportunity to improve the determination of these carcinogens in food and make the analysis more widely available. Developments in liquid chromatography-mass spectrometry should provide an avenue for renewed interest in non-volatile N-nitrosamines, and could help with the identification of novel compounds whose presence is suggested by the high apparent total N-nitroso content of some foods.

Development of liquid chromatography/mass spectrometry methods for the quantitative analysis of herbal medicine in biological fluids: a review

The development of liquid chromatography-mass spectrometry (LC-MS) and tandem MS/MS for the analysis of bioactive components and their metabolites of herbal medicines in biological fluids is reviewed with the aim of providing an overview of the current techniques and methods used. The issues and challenges associated with various stages of the analytical method development are discussed using Ginkgo biloba and Panax ginseng as case studies. LC-MS offers selectivity and specificity in both the chromatographic separation and detection steps. This is necessary in order to measure compounds at extremely low concentrations as is often observed in plasma and urine samples. Traditional methods of detection (UV-visible) do not offer sufficient selectivity and specificity needed. The strategies and pitfalls involved with the measurement of such compounds are discussed in this review. Matrix effects, 'unseen' matrix suppression and enhancement ionization effects can significantly reduce the accuracy and precision of the measurement. The impact of the correct choice of chromatography column formats on signal-to-noise ratio is also discussed. Analytical methods from sample preparation to mass spectrometric detection is outlined in order to provide good direction for analysts intent on the measurement of bioavailable compounds from herbal medicines in plasma and urine samples.

Current developments in LC-MS for pharmaceutical analysis.

The current developments in liquid chromatography-mass spectrometry (LC-MS) and its applications to the analysis of pharmaceuticals are reviewed. Various mass spectrometric techniques, including electrospray and nanospray ionization, atmospheric pressure chemical ionization and photoionization and their interface with liquid chromatographic techniques are described. These include high performance liquid chromatography, capillary electrophoresis and capillary electrochromatography and the advantages and disadvantages of each technique are discussed. The applications of LC-MS to the studies of in vitro and in vivo drug metabolism, identification and characterization of impurities in pharmaceuticals, analysis of chiral impurities in drug substances and high-throughput LC-MS-MS systems for applications in the "accelerated drug discovery" process are described.

Development of generic liquid chromatography-mass spectrometry methods using experimental design

Standard approaches to development of liquid chromatography-mass spectrometry (LC-MS) methods, either ion-pairing or reversed-phase liquid chromatography, have been through trial and error or intentional variation of experimental factors. These approaches to method optimization fail to take into account interactions between experimental factors and therefore the results may not be optimal for the combination of experimental factors. Another approach to optimization is through the use of chemometrics. Chemometric approaches can be more efficient than trial and error or intentional variation because chemometrics make use of multivariate designs; experimental factors are varied simultaneously at the various levels. Therefore chemometrics can take into account interactions between factors. The goal of this study was to develop a generic ion-pair LC-MS method for the analysis of acidic compounds using a chemometric approach called design of experiments (DOE). Four acidic compounds which cover three classes of acidic functional groups: 1-naphthyl phosphate ( 1), 1-naphthalenesulfonic acid ( 2), 2-naphthalenesulfonic acid ( 3), and (1-naphthoxy)acetic acid ( 4) were used as model compounds to develop the generic method. This study illustrates that LC-MS conditions can be optimized efficiently with minimal amount of experimentation using a chemometric approach to experimental design.

Liquid Chromatography-Mass Spectrometry: Bioanalytical Applications in PHarmacokinetics and Toxicokinetics.

With the increasing need for reliable and comprehensive pharmacokinetic data from diverse nonclinical as well as clinical studies, a sensitive and specific bioanalytical technique is essential. Such a technique is liquid chromatography-mass spectrometry (LC-MS). This article provides a brief overview of the key developments in LC-MS and focuses on the more recent LC-MS ionisation/interfacing technique, that of atmospheric pressure ionisation (API). The advantages of LC-API-MS/MS for routine bioanalysis, in terms of sensitivity, specificity and reproducibility are discussed. Recent scientific literature is cited that exemplifies the capabilities, applications and usefulness of this powerful analytical technique in pharmacokinetics/toxicokinetics studies.