Development of a non-separative screening strategy based on mass spectrometry for the semi-quantification of urinary polycyclic aromatic hydrocarbon metabolites.

A fast and non-separative screening strategy is presented for the analysis of five urinary metabolites of polycyclic aromatic hydrocarbons (PAHs), namely 2-naphthol, 1-acenaphthenol, 2-hydroxyfluorene, 9-phenanthrol and 1-hydroxypyrene. These hydroxylated derivatives (OH-PAHs) were subjected to enzymatic hydrolysis and were extracted from urine using a liquid-liquid extraction (LLE). The profile signals were obtained by direct injection of the sample into a programmed temperature vaporizer coupled to a quadrupole mass spectrometer via a deactivated fused silica tubing (PTV-qMS).

Determination of Aminoglycosides by Ion-Pair Liquid Chromatography with UV Detection: Application to Pharmaceutical Formulations and Human Serum Samples.

Aminoglycosides (AGs) represent a prominent class of antibiotics widely employed for the treatment of various bacterial infections. Their widespread use has led to the emergence of antibiotic-resistant strains of bacteria, highlighting the need for analytical methods that allow the simple and reliable determination of these drugs in pharmaceutical formulations and biological samples. In this study, a simple, robust and easy-to-use analytical method for the simultaneous determination of five common aminoglycosides was developed with the aim to be widely applicable in routine laboratories.

Rapid and reliable quantification of urinary malondialdehyde by HILIC-MS/MS: A derivatization-free breakthrough approach.

Background: The development of fast analytical methods is crucial for the research, discovery, and confirmation of crucial biomarkers. Furthermore, the implementation of fast analytical strategies contributes to efficient and time-effective procedures. In this sense, analysis of malondialdehyde (MDA) has become an important tool for understanding the role of oxidative stress in various diseases and for evaluating the efficacy of therapeutic interventions.

In-situ acetylation followed by liquid-liquid extraction and gas chromatography - mass spectrometry for the determination of bromophenols in urine.

A novel and simple method combining in-situ acetylation, liquid-liquid extraction and gas chromatography-mass spectrometry (GC-MS) has been developed for the quantification of 10 bromophenols in urine, used as biomarkers of exposure to polybrominated diphenyl ethers. The analytical process involves an enzymatic hydrolysis of the bromophenol glucuronide fraction followed by an aqueous derivatization of the phenol group with acetic anhydride. A subsequent liquid-liquid extraction of the sample with hexane allows the injection of the organic layer, using a programmed temperature vaporizer, into a gas chromatograph coupled to a single quadrupole mass spectrometer.

Heart-Cutting Bidimensional Liquid Chromatography for the Simultaneous Analysis of Veterinary Drugs Residues and Nucleotide Monophosphates in Sheep's Milk.

Sheep's milk is a significant source of nucleotide monophosphates (NMPs) but can also contain undesirable residues from veterinary drugs, posing a potential human health risk. This study introduces a novel application of two-dimensional liquid chromatography (2D-LC), in heart-cutting mode, for the simultaneous determination of nucleotides and veterinary drug residues in sheep's milk. 2D-LC allows for the separation of these compounds in a single chromatographic run despite their differing physicochemical properties.

Simultaneous determination of favipiravir and surrogates of its metabolites by means of heart-cutting bidimensional liquid chromatography (2D-LC).

Therapeutic monitoring of drugs, particularly those with multiple metabolites, can be time-consuming and labor-intensive due to the need for different analytical methods depending on the specific metabolite or matrix of interest. In this study, we employed a heart-cutting 2D-LC separation method based on the coupling of reversed-phase and mixed-mode mechanisms to determine Favipiravir and surrogates of five main metabolites. This approach was applied to serum, plasma, urine, and human peripheral blood mononuclear cells.

Use of a guard column coupled to mass spectrometry as a fast semi-quantitative methodology for the determination of plasticizer metabolites in urine.

For the first time, a very simple and fast method combining the use of a guard column coupled to tandem mass spectrometry (guard column-MS/MS) has been proposed for the determination of plasticizer metabolites in urine. Briefly, samples (1.0 mL) were submitted to enzymatic hydrolysis for 10 min, filtered, diluted 1/10 v/v with ultrapure water and directly injected into the system.

Determination of Hydroxy Polycyclic Aromatic Hydrocarbons in Human Urine Using Automated Microextraction by Packed Sorbent and Gas Chromatography-Mass Spectrometry.

A fast methodology for the determination of monohydroxy polycyclic aromatic hydrocarbons in human urine using a fully automated microextraction by packed sorbent coupled to a gas chromatograph-mass spectrometer is reported. Sample preparation requires simple hydrolysis, centrifugation, filtration, and dilution. The method does not require a derivatization step prior to analysis with gas chromatography and allows the measurement of up to three samples per hour after hydrolysis.

Development of a method for the determination of polyamines including N-acetylated forms in human saliva via benzoylation and gas chromatography-mass spectrometry.

A simple method for the determination of polyamines and their N-acetylated forms was developed using benzoyl chloride as derivatization reagent, and 1,6-diaminohexane as internal standard, followed by liquid-liquid extraction with ethyl acetate. The organic extract was injected in a gas chromatograph using a programmed temperature vaporizer and the determination and quantification was performed with a quadrupole mass spectrometer. There was no matrix effect with the proposed method, so internal calibration was used to quantify the corresponding derivatives.

Determination of leucine and isoleucine/allo-isoleucine by electrospray ionization-tandem mass spectrometry and partial least square regression: Application to saliva samples.

Herein we propose, for the first time, a rapid method based on flow injection analysis, electrospray ionization-tandem mass spectrometry (FIA-ESI-MS/MS) and multivariate calibration for the determination of l-leucine, l-isoleucine and L-allo-isoleucine in saliva. As far as we know, multivariate calibration has never been applied to the data from this non-separative approach. The possibilities of its use were explored and the results obtained were compared with the corresponding ones when using univariate calibration.

Non-separative method based on a single quadrupole mass spectrometer for the semi-quantitative determination of amino acids in saliva samples. A preliminary study.

Amino acids have been of great interest in clinical studies since variation in their concentration may provide information about different disorders. For the first time, a non-separative method based on single quadrupole mass spectrometry (qMS) for the simultaneous semiquantitative determination of sixteen amino acids in saliva samples has been developed. The method includes derivatisation of amino acids with ethyl chloroformate-pyridine-ethanol to obtain volatile products, liquid-liquid extraction (LLE) and further analysis using a programmed temperature vaporizer (PTV) coupled to qMS.

Multiple headspace sampling coupled to a programmed temperature vaporizer to improve sensitivity in headspace-gas chromatography. Determination of aldehydes.

The improvement of sensitivity in headspace (HS) sampling of not very volatile analytes constitutes a challenge that has usually been approached through coupling with additional techniques. Here we propose a new methodology for increasing sensitivity through a multistep approach. This proof of concept is based on direct coupling of a headspace sampler with a programmed temperature vaporizer (PTV) and a gas chromatograph (GC), with mass spectrometry (MS) detection.

Determination of polyamines and related compounds in saliva via in situ derivatization and microextraction by packed sorbents coupled to GC-MS.

Here we show the determination of different polyamines (putrescine, cadaverine, spermidine) and related compounds (gamma-aminobutyric acid and l-ornithine) in saliva samples. These compounds are known to be biomarkers for several diseases. We have optimised an in situ derivatization process using ethyl chloroformate, an automated microextraction by packed sorbent and the determination of the corresponding products using a programmed temperature vaporizer coupled to a gas chromatograph - mass spectrometer.

Development of a screening and confirmatory method for the analysis of polar endogenous compounds in saliva based on a liquid chromatographic-tandem mass spectrometric system.

In this paper, a high-throughput approach is proposed for the sensitive screening and the confirmatory analysis of polar compounds in saliva using a two-step approach based on a liquid chromatographic system coupled to a triple quadrupole mass spectrometer. A reversed-phase chromatographic column was used in both steps and changes in the composition of the mobile phase allowed the screening and the confirmatory analyses to be performed with the same instrumental configuration. The proposed strategy has been tested for the determination of a multiclass group of polar endogenous compounds (creatinine, polyamines and amino acids) in saliva samples.

Non-separative mass spectrometry methods for non-invasive medical diagnostics based on volatile organic compounds: A review.

In this review, an assessment of non-separative methods based on mass spectrometry used to analyse volatile organic compounds in the field of bioanalysis is performed. The use of non-separative methods based on mass spectrometry has been established as an attractive option for analysing compounds. These instrumental configurations are suitable for biomedical applications because of their versatility, rapid output of results, and the wide range of volatile organic compounds that can be determined.

Liquid-liquid extraction-programmed temperature vaporizer-gas chromatography-mass spectrometry for the determination of polycyclic aromatic hydrocarbons in saliva samples. Application to the occupational exposure of firefighters.

We present the development and validation of a sensitive method for the reliable determination of sixteen polycyclic aromatic hydrocarbons (PAHs) in saliva samples, which can be used as exposure markers. This method was based on a liquid-liquid extraction and programmed temperature vaporizer-gas chromatography-mass spectrometry analysis (LLE-PTV-GC-MS). Since no matrix effect was found, quantification was performed using external calibration.

Quantitative and qualitative analysis of polycyclic aromatic hydrocarbons in urine samples using a non-separative method based on mass spectrometry.

In this work, a method for the quantitative and qualitative analysis of 11 polycyclic aromatic hydrocarbons (PAHs) in urine samples is reported. The method is based on the coupling of a programmed temperature vaporizer (PTV) with a quadrupole mass spectrometer (qMS), via a deactivated fused silica tubing. Before the PTV-qMS analysis, the samples were subjected to a liquid-liquid extraction (LLE).

Urinary volatile fingerprint based on mass spectrometry for the discrimination of patients with lung cancer and controls.

Profile signals of urine samples corresponding to patients with lung cancer and controls were obtained using a non-separative methodology. The method is based on the coupling of a headspace sampler, a programed temperature vaporizer and a mass spectrometer (HS-PTV-MS). With only a centrifugation step as prior sample treatment, the samples were subjected to the headspace generation process and the volatiles generated were introduced into the PTV where they were trapped in the Tenax® packed liner while the solvent was purged.

Determination of ketones and ethyl acetate-a preliminary study for the discrimination of patients with lung cancer.

In this work, ten possible volatile biomarkers of lung cancer (acetone, 2-butanone, ethyl acetate, 2-pentanone, 4-methyl-2-pentanone, 2-hexanone, 3-heptanone, 2-heptanone, 3-octanone, and 2-nonanone) have been analyzed to evaluate their different concentration levels in urine samples from lung cancer patients (n = 12) and healthy controls (n = 12). The volatile compounds were generated with a headspace autosampler and analyzed with a gas chromatograph equipped with a programmed temperature vaporizer and mass spectrometry detector (HS-PTV-GC-MS). With the aim of evaluating the aforementioned differences, a Mann-Whitney U test and box-plots were obtained.

Headspace-programmed temperature vaporizer-mass spectrometry and pattern recognition techniques for the analysis of volatiles in saliva samples.

A rapid method for the analysis of volatiles in saliva samples is proposed. The method is based on direct coupling of three components: a headspace sampler (HS), a programmable temperature vaporizer (PTV) and a quadrupole mass spectrometer (qMS). Several applications in the biomedical field have been proposed with electronic noses based on different sensors.

Use of microextraction by packed sorbent directly coupled to an electron ionization single quadrupole mass spectrometer as an alternative for non-separative determinations.

Sometimes it is not necessary to separate the individual compounds of a sample to resolve an analytical problem, it is enough to obtain a signal profile of the sample formed by all the components integrating it. Within this strategy, electronic noses based on the direct coupling of a headspace sampler with a mass spectrometer (HS-MS) have been proposed. Nevertheless, this coupling is not suitable for the analysis of non-volatile compounds.

Derivatization coupled to headspace programmed-temperature vaporizer gas chromatography with mass spectrometry for the determination of amino acids: Application to urine samples.

A new method based on headspace programmed-temperature vaporizer gas chromatography with mass spectrometry has been developed and validated for the determination of amino acids (alanine, sarcosine, ethylglycine, valine, leucine, and proline) in human urine samples. Derivatization with ethyl chloroformate was employed successfully to determine the amino acids. The derivatization reaction conditions as well as the variables of the headspace sampling were optimized.

Headspace-programmed temperature vaporization-mass spectrometry for the rapid determination of possible volatile biomarkers of lung cancer in urine.

We propose a new method for the rapid determination of five volatile compounds described in the literature as possible biomarkers of lung cancer in urine samples. The method is based on the coupling of a headspace sampler, a programmed temperature vaporizer in solvent-vent injection mode, and a mass spectrometer (HS-PTV-MS). This configuration is known as an electronic nose based on mass spectrometry.