Background: Aflatoxins (AFs), as secondary metabolites, are mainly produced by fungi of Aspergillus genus. The determination of contamination rate, dietary exposure, and health risk assessment for aflatoxin M1 (AFM1) was conducted aimed to estimate potential health risks for the population of North Macedonia. Methods: A total of 974 dairy samples, including 404 Ultra-High Temperature (UHT) mil...

A high-performance liquid chromatographic method using fluorescence detection for the simultaneous determination of furosemide and amiloride is described. The chromatographic system is based on reversed-phase ion-pair chromatography with sodium dodecylsulphate as ion-pairing agent. The same counter-ion is used for the ion-pair liquid-liquid extraction to ethyl acetate. The minimum detectable co...

A simple and sensitive determination method for selenomethionine (Se-Met) using an HPLC-fluorescence detection system coupled with an on-line electrochemical reactor has been developed. NBD-F (4-fluoro-7-nitro-2,1,3-benzoxadiazole) was used as the fluorescent derivatization reagent for Se-Met. NBD-Se-Met was separated from NBD-derivatives of 22 other amino acids within 35 min. Applying an optim...

A highly sensitive and selective high-performance liquid chromatographic (HPLC) method has been developed for the determination of microbial lipopeptides of fluorescent derivatization with 1-bromoacetylpyrene to overcome the limitations of trace detection of lipopeptides in aqueous solutions. The derivatization of lipopeptides with 1-bromoacetylpyrene was conducted at 60°C for 20 min under cata...

A sensitive high-performance liquid chromatographic (HPLC) method is described for the determination of posaconazole in human plasma/serum. The method is based on a single dilution step by treating the sample with methanol, and followed by the direct injection of the sample into the HPLC system. Posaconazole and internal standard ketoconazole in the methanol extract are subsequently analyzed by...

9-(2-Phosphonylmethoxyethyl)adenine (PMEA), (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA), and (R,S)-9-(3-fluoro-2-phosphonylmethoxypropyl)adenine (FPMPA) are selective antiviral agents with activity against a broad spectrum of DNA viruses and retroviruses. A highly sensitive method has been developed to determine concentrations of these compounds in human plasma. Plasma samples co...

A simple, selective and sensitive high-performance liquid chromatographic method with fluorescence detection is described for the simultaneous determination of catecholamines and 5-hydroxyindoleamines. The method is based on the derivatization of the amines with benzylamine in the presence of potassium hexacyanoferrate(III) under mild conditions. The resulting fluorescent derivatives are separa...

Reversed-phase high-performance liquid chromatographic (HPLC) behavior of fluorescent labeled phospholipids (PLs) was studied. Molecular species of phosphatidylethanolamine (PE) derivatized with fluorescein-, thiocarbamoyl-, pyrenesulfonyl-, and dimethylaminonaphthalenesulfonyl (dansyl)-fluorophores were separated on octadecylsilica with a mobile phase of acetonitrilemethanol-water in the prese...

A sensitive and specific HPLC method has been developed for the assay of amlodipine in human plasma. The assay involves derivatization with 4-chloro-7-nitrobenzofurazan (NBD-Cl), solid-phase extraction on a silica column and isocratic reversed-phase chromatography with fluorescence detection. Nortriptyline hydrochloride was used as an internal standard. The assay was linear over the concentrati...

A rapid, reliable and rugged assay for determining codeine in human plasma using reversed-phase high-performance liquid chromatography with fluorescence detection was developed. This analytical method utilized an ion-exchange/mixed-mode solid-phase extraction procedure. The chromatographic separation was achieved using a 150 x 4.6 mm I.D., 3-microns reversed-phase C8 (deactivated for basic anal...