Francesca Buiarelli

Determination of phenolic acids in wine by high-performance liquid chromatography with a microbore column

Abstract A method for the extraction and separation of the non-volatile phenolic acids of wine is described. The extracts are analysed by HPLC with a microbe column and UV detection. The free phenolic acids and depsides in different wine samples were identified and determined.

ANALYSIS BY HPLC-MS/MS OF BIOPHENOLIC COMPONENTS IN OLIVES AND OILS

The aim of this work was to analyze by HPLC-MS-MS natural biophenolic compounds in complex natural samples like olives and olive oils. Eleven benzoic and cinnamic acids, vanillin and other eight biophenolic compounds were studied by liquid chromatography-atmospheric pressure ionization mass spectrometry/mass spectrometry with a Turbo Ion source in the negative mode. To confirm the specific presence, with great sensitivity, of such compounds in olive samples, in brine samples and in extravirgin olive oil the fragmentation of precursor ions into the product species acquisition was used in Multiple Reaction Monitoring (MRM) mode.

Validation study on avermectine residues in foodstuffs

Avermectines are antiparasitic agents widely used as veterinary drugs for food producing animals. The European Community, due to their side effects, limited the use of these molecules establishing maximum residue limits (MRLs) in some foods. A validated qualitative and quantitative high performance liquid chromatography method with fluorescence detection (HPLC-FL) is presented for the simultaneous determination of ivermectin (IVM), abemectin (ABA), moxidectin (MOX), eprinomectin (EPR), doramectin (DOR) and emamectin (EMA) in foodstuffs (muscle, eggs and milk). Samples were extracted with acetonitrile, purified with liquid-liquid extraction (LLE), and analysed by HLPC-FL previous derivatization with trifluoroacetic anhydride (TFAA) in presence of 1-methyl-imidazole (MI) and acetic acid. To date, the presented method is the first validated for the matrix eggs, and in accordance with the requirements set by Commission Decision 2002/657/EC. Recoveries of the methods, calculated spiking the samples in the range 5.0-100.0 μg kg(-1), were 64-83% for muscle, 65-89% for milk and 63-84% for eggs. The precision (CV) ranged between 9.2 and 17.1% for muscle, 9.9 and 16.6% for milk and from 9.4 to 17.4% for eggs. Linearity for the six analytes was calculated from 5.0 to 200.0 μg kg(-1). The main advantages of the presented method are its rapidity, the specificity, the good precision and recovery that make it very suitable to the detection and determination of avermectines.

Analysis of lemon and bergamot essential oils by HPLC with microbore columns

SummarySome citrus essential oils were analyzed by HPLC with both microbore and standard columns in reversed and normal phase. Volatile and non-volatile fraction were investigated. In the non-volatile fraction some coumarins have been identified. Fractions are detected spectrophotometrically at 220 nm and 320 nm before and after evaporation of samples. Some components were also identified by LC/MS.

Development of a method for the analysis of underivatized amino acids by liquid chromatography/tandem mass spectrometry: Application on Standard Reference Material 1649a (urban dust)

A liquid chromatography-tandem mass spectrometry analytical procedure has been developed for the detection and quantitative determination of underivatized amino acids at low concentrations in a Standard Reference Material-urban dust. In order to minimize interferences of other compounds, an accelerated solvent extraction followed by a solid phase extraction on two different cartridges was applied prior to LC-MS-MS. Fourteen amino acids were separated by high resolution liquid chromatography, detected and quantified by multiple reaction monitoring on a triple quadrupole. The proposed methodology has been applied for the first time on Standard Reference Material 1649a (urban dust) from the National Institute of Standards and Technology, that does not report certification values for these compounds. This methodology avoids the derivatization step and allows the amino acid quantification in a complex matrix, such as that of atmospheric particulate matter, and represent a good method suitable to analyze this class of compounds in atmospheric aerosol. The selected strategy demonstrated to be fit-for-purpose, by applying it to a real atmospheric sample with the aim to verify the efficacy of the study and to provide information about the organic matter content.

Identification of hydrocarbon sources in contaminated soils of three industrial areas

The present paper deals with identification of hydrocarbon sources in contaminated soil of three tank farms located in north, central and south Italy. Parent polycyclic aromatic hydrocarbons (naphthalene through benzo(g,h,i)perylene) and n-alkanes (n-C10 through n-C36) were determined. The study of source assignments was carried out by their distribution patterns, their diagnostic ratios, and determination of less-commonly used markers. The data show anthropogenic and biogenic origin of n-alkanes and petrogenic and pyrolytic sources of PAHs. Multiple sources of hydrocarbons, that were not considered in the preliminary environmental assessments, are identified. The application of a multi-criteria approach allows to locate petroleum pollution sources that affect the study sites. The results demonstrate that the application of a multi-criteria approach for source identification is a key point to assess environmental damage and prove that an accurate study of source identification has to be performed. The suggested methodology is a useful tool to manage contaminated sites and to plan appropriate interventions of clean up.

Analysis of orange and mandarin essential oils by HPLC

SummaryThe analysis of orange and mandarin essential oils (nonvolatile fraction) was carried out by HPLC in normal and reverse phase modes with UV and spectrofluorimetric detection in series.For the identification of chromatographic peaks a preparative HPLC was used, the purified fractions were analyzed by GC-MS and by LC-MS. Some flavones were found in these oils.

Determination of nandrolone metabolites in human urine: comparison between liquid chromatography/tandem mass spectrometry and gas chromatography/mass spectrometry

Nandrolone (19-nortestosterone) is an androgenic anabolic steroid illegally used as a growth-promoting agent in animal breeding and as a performance enhancer in athletics. Therefore, its use was officially banned in 1974 by the Medical Commission of the International Olympic Committee (IOC). Following nandrolone administration, the main metabolites in humans are 19-norandrosterone, 19-norethiocolanolone and 19-norepiandrosterone, and their presence in urine is the basis of detecting its abuse. The present work was undertaken to determine, in human urine, nandrolone metabolites (phase I and phase II) by developing and comparing multiresidue liquid chromatography/tandem mass spectrometry (LC/MS/MS) and gas chromatography/mass spectrometry (GC/MS) methods. A double extraction by solid-phase extraction (SPE) was necessary for the complete elimination of the interfering compounds. The proposed methods were also tested on a real positive sample, and they allow us to determine the conjugated/free fractions ratio reducing the risk of false positive or misleading results and they should allow laboratories involved in doping control analysis to monitor the illegal use of steroids. The advantages of LC/MS/MS over GC/MS (which is the technique mainly used) include the elimination of the hydrolysis and derivatization steps: it is known that during enzymatic hydrolysis several steroids can be converted into related compounds and deconjugation is not always 100% effective. The validation parameters for the two methods were similar (limit of quantification (LOQ) <1 ng/mL and percentage coefficient of variance (CV%) <16.4), and both were able to confirm unambiguously all the analytes, thus confirming the validity of both techniques.

Development and validation of an MEKC method for determination of nitrogen‐containing drugs in pharmaceutical preparations

A fast and accurate micellar electrokinetic capillary chromatography method was developed for quality control of pharmaceutical preparations containing cold remedies as acetaminophen, salicylamide, caffeine, phenylephrine, pseudoephedrine, norephedrine and chlorpheniramine. The method optimization was realized on a Beckman P/ACE System MDQ instrument. The baseline separation of seven analytes was performed in an uncoated fused silica capillary internal diameter (ID)=50 µm using tris‐borate (20 mM, pH=8.5) containing sodium dodecyl sulphate 30 mM BGE. On line‐UV detection at 214 nm was performed and the applied voltage was 10 kV. The operating temperature was 25°C. After experimental conditions optimization, the proposed method was validated. The evaluated parameters were: precision of migration time and of corrected peak area ratio, linearity range, limit of detection, limit of quantification, accuracy (recovery), ruggedness and applicability. The method was then successfully applied for the analysis of three pharmaceutical preparations containing some of the analytes listed before.

Analysis of bitter essential oils from orange and grapefruit by high-performance liquid chromatography with microbore columns

The analysis of bitter orange and grapefruit essential oils (non-volatile fraction) was carried out by HPLC in normal- and reversed-phase mode with UV detection. These oils were compared with the sweet orange and mandarin essential oils, analyzed previously. For the identification of chromatographic peaks, fractionation by RP-HPLC was carried out. The purified fractions were analyzed by GC-MS and LC-MS. Some new compounds were found, together with many others already identified in different citrus essential oils.