Qualitative and quantitative analysis of N-acetyllactosamine and lacto-N-biose, the two major building blocks of human milk oligosaccharides in human milk samples by high-performance liquid chromatography-tandem mass spectrometry using a porous graphitic carbon column.

This study presents a validated, porous graphitic carbon stationary phase-based LC-MS/MS method for the identification and quantification of lacto-N-biose (LNB) and N-acetyllactosamine (LacNAc). These compounds are the major building blocks of human milk oligosaccharides, however the presence of their unbound form in human milk has not been examined so far. The separation of these highly related structures in their alditol form was accomplished by a gradient LC method and multiple reaction monitoring (MRM) analysis after appropriate sample preparation including size-exclusion chromatography and solid-phase extraction.

Exploring the possibilities of capacitively coupled contactless conductivity detection in combination with liquid chromatography for the analysis of polar compounds using aminoglycosides as test case.

The analysis of highly polar (often charged) compounds which lack a strong UV absorbing chromophore is really challenging. Despite the numerous analytical methods published, the demand for a simple, robust and cheap technique for their analysis still persists. Here, reversed phase (RP) liquid chromatography (LC) with capacitively coupled contactless conductivity detection (C(4)D) was explored for the first time as a possible method for separation and detection of various aminoglycoside (AMG) antibiotics which were taken as typical test compounds: tobramycin (TOB), spectinomycin, streptomycin, amikacin, kanamycin A and kanamycin B.

Qualitative and quantitative analysis of PDE-5 inhibitors in counterfeit medicines and dietary supplements by HPLC-UV using sildenafil as a sole reference.

Due to their popularity, medicinal products containing the phophodiesterase type 5 enzyme (PDE-5) inhibitors sildenafil, vardenafil and tadalafil are often subject to counterfeiting. In addition, illicit herbal dietary supplements adulterated with these substances or their analogs have appeared on the market offering an easy and anonymous sale. This paper describes an analytical method for qualitative and quantitative screening of sildenafil, vardenafil, tadalafil and 11 of their designer analogs in illegal erectile dysfunction products by high-performance liquid chromatography with UV detection (HPLC-UV).

Detection and structure elucidation of hydroxythiovardenafil as an adulterant in a herbal dietary supplement.

A new derivative of vardenafil was detected in an alleged herbal dietary supplement and identified as 2-(2-ethoxy-5-(4-(2-hydroxyethyl)piperazin-1-ylsulfonyl)phenyl)-5-methyl-7-propyl-imidazo[1,5-f][1,2,4]triazin-4(3H)-thione. Structure elucidation was carried out by LC-UV-MS/MS and NMR. Results obtained with high resolution MS and IR spectroscopy confirmed the proposed chemical structure.

Detection and identification of the new potential synthetic cannabinoids 1-pentyl-3-(2-iodobenzoyl)indole and 1-pentyl-3-(1-adamantoyl)indole in seized bulk powders in Hungary.

3-Naphthoyl- and 3-phenylacetylindoles represent a group of substances of cannabimimetic activity with affinities - strongly influenced by their functional groups - to cannabinoid receptors CB1 and CB2. Some of them have been described as ingredients of herbal blends also known as "smart products" by several research groups. Recently further cannabimimetic substances possessing new chemical structures like benzoylindoles and adamantoylindoles have emerged.

Identification and characterization of the new designer drug 4'-methylethcathinone (4-MEC) and elaboration of a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) screening method for seven different methcathinone analogs.

A fast and simple LC-MS/MS method was developed for screening mephedrone, butylone, methylenedioxypyrovalerone (MDPV), flephedrone, methylone and methedrone in bulk powder samples. Samples were separated on a reverse phase column using gradient elution with mixtures of water, acetonitrile and formic acid. After optimization a limit of detection of about 2ngmL(-1) was achieved using multiple reaction monitoring (MRM) mode.

Sulfate esters of morphine derivatives: synthesis and characterization.

Sixteen 3-O- and 6-O-sulfate esters of morphine, codeine and some of their N-methyl quaternary derivatives were synthesized by means of sulfation with pyridine-SO(3) complex and sulfuric acid/N,N'-dicyclohexylcarbodiimide. Complete (1)H- and (13)C-NMR assignments are given for each of the synthesized compounds based on one- and two-dimensional homo- and heteronuclear measurements. Comparative analysis of chiral properties by circular dichroism and optical rotatory dispersion revealed characteristic differences in the spectra due to changes in charge, polarity and intramolecular association by strong hydrogen bonds in aqueous solution.

Determination of paracetamol and its main impurity 4-aminophenol in analgesic preparations by micellar electrokinetic chromatography.

A micellar electrokinetic chromatographic (MEKC) method was developed for the quality control of paracetamol containing pharmaceutical preparations. The influence of several factors (surfactant concentration, buffer concentration, pH and applied voltage) was studied during development and optimisation of the method. Phosphate buffer (pH 9.