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Chlorogenic acid (CQA) is one of phenolics commonly found in higher plants, possessing numerous health-promoting effects on humans. Unfortunately, it is easily degraded/transformed into other substances during extraction. Therefore, its reliable analysis requires a special approach that does not involve high temperatures. This paper presents a very simple method of CQA isolation using the sea sand disruption method with subsequent purification of the extract using the ion-pair solid-phase extraction process, followed by HPLC–DAD detection. It was found that control of the ion pairing reagent concentration and sample pH is crucial to improve purification, and that the best results, with recovery exceeding 98%, were obtained for 0.05 M tetrabutylammonium bisulfate at pH 7 when the ion pairs were formed directly in the extract and eluted from the C18 sorbent using an acidified methanol–water mixture. The practical potential of the developed procedure was verified by using it for CQA isolation from different plants. The approach represents one of the contemporary analytical trends and current advances in the solid phase extraction, in which several sorption extraction techniques are combined to ensure high-quality analytical results. [ABSTRACT FROM AUTHOR]

Introduction: Effective diagnosis of cardiovascular diseases requires the right tools to be used enabling selective and sensitive analysis of their biomarkers. One of them is homocysteine (Hcy), nowadays determined by immunoassays and chromatographic methods. This study aims to compare the results obtained by direct chemiluminescence immunoassay (CLIA) and high performance liquid chromatography with fluorescent detection (HPLC-FD) using commercial kits. Materials and methods: Homocysteine concentration was determined in serum samples obtained from 101 individuals, using Atellica IM HCY (Siemens Healthineers, Erlangen, Germany) and HCY in plasma/serum - HPLC-FD (Chromsystems Instruments & Chemicals GmbH, Gräfelfing, Germany) tests validated for routine analysis. The latter was applied as a reference method. The comparability and agreement between the tested methods were evaluated using the Passing-Bablok (PB) regression analysis and the Bland-Altman (BA) method of the differences analysis. Results: Studies showed that CLIA gives higher Hcy concentrations (15.7 ± 4.14 µmol/L). Passing-Bablok regression analysis of the results obtained with CLIA (y) compared with HPLC-FD (x) yielded an intercept of 0.22 (95%CI: - 2.16 to 2.46) and slope of 1.58 (95%CI: 1.33 to 1.87). Bland-Altman analysis demonstrated a systematic positive bias for CLIA of 5.85 ± 2.77 µmol/L. Conclusions: Methods disagreement precludes their interchangeability. Lower Hcy values by HPLC-FD result from its greater selectivity. High performance liquid chromatography with fluorescent detection should be considered as preferential method for analysing Hcy in blood serum as well as the recommended reference method for routine clinical analysis. This fact, however, imposes the need to establish new reference ranges. [ABSTRACT FROM AUTHOR]

The analytical procedures for determining plant constituents involve the application of sample preparation methods to fully isolate and/or pre-concentrate the analyzed substances. High-temperature liquid extraction is still applied most frequently for this purpose. The present paper shows that high-temperature extraction cannot be applied for the analysis of chlorogenic acids (CQAs) and their derivatives in plants as it causes the CQAs transformation leading to erroneous quantitative estimations of these compounds. Experiments performed on different plants (black elder, hawthorn, nettle, yerba maté, St John’s wort and green coffee) demonstrate that the most appropriate method for the estimation of CQAs/CQAs derivatives is sea sand disruption method (SSDM) because it does not induce any transformation and/or degradation processes in the analyzed substances. Owing to the SSDM method application we found that the investigated plants, besides four main CQAs, contain sixteen CQAs derivatives, among them three quinic acids. The application of SSDM in plant analysis not only allows to establish a true concentration of individual CQAs in the examined plants but also to determine which chlorogenic acids derivatives are native plant components and what is their concentration level. What is even more important, the application of SSDM in plant analysis allows to eliminate errors that may arise or might have arisen in the study of chlorogenic acids and their derivatives in plant metabolism. [ABSTRACT FROM AUTHOR]

This study deals with the sea sand disruption method (SSDM) in sample preparation for chromatographic analysis of quercetin in different plants. Several SSDM variables were tested in relation to quercetin recovery: sample to sand mass ratio, type of dispersing liquid, volume of the solvent applied for analyte elution, and the time of grinding. The optimized procedure has been applied for the extraction of quercetin from the edible and inedible parts of different varieties of onion, apples, and tea. The SSDM results are comparable with those obtained by pressurized liquid extraction, regarded as one of the most effective sample preparation techniques. The presented results show that the hydrolysis of quercetin glycoside form in SSDM conditions does not occur or is negligible. Hence, the method is especially useful when the estimation of the real amount of aglycones in plants is required. [ABSTRACT FROM AUTHOR]

Four types of solvent extraction methods (ultrasound and microwave assisted extraction, pressurized liquid extraction, and extraction in the Soxhlet apparatus) for paclitaxel, cephalomannine, and 10-deacetylbaccatin, taxoids recovered from common yew twigs, were compared. By use of pressurised liquid extraction (PLE), the most effective extractant of taxoids was determined. HPLC was used for the analysis of the extracts. Comparison of the obtained results revealed differences in the extraction power of the applied methods. The greatest yields were obtained by multiple PLE, which can be recommended as the best sample preparation method for taxoids analysis in yew twigs. [ABSTRACT FROM AUTHOR]

The accelerated solvent extraction (ASE) procedure has been examined as a sample preparation method for the HPLC analysis of rutin and isoquercitrin in Sambucus nigra L. The experimental extraction parameters (solvent composition, temperature, operation pressure, and static extraction time) have been optimized in order to receive the best recovery of both analytes from the flowers, leaves, and berries of black elder. The ASE recoveries obtained under the optimal extraction conditions were compared with analogous ones obtained by means of the maceration technique. [ABSTRACT FROM AUTHOR]