Automatic spot preparation and image processing of paper microzone-based assays for analysis of bioactive compounds in plant extracts

The colorimetric determination of the concentration of phytochemicals in plant extract samples using a spotting automatic system, mobile phone camera and a computer with developed software for quantification is described. Method automation was achieved by using a robotic system for spotting. The instrument was set to disperse the appropriate aliquots of the reagents and sample on a Whatman paper sheet. Spots were photographed and analysed by ImageJ software or by applying the developed MatLab based algorithm. The developed assay was found to be effective, with a linear response at the concentration range of 0.03-0.25g/L for polyphenols. The detection limit of the proposed method is sub 0.03g/L. The paper microzone-based assays for flavonoids and amino acids/peptides were also developed and evaluated as applicable. Comparing the results with conventional PμZP methods demonstrates that both methods yield similar results. At the same time, the proposed method has an attractive advantage in analysis time and repeatability/reproducibility.

Characterization of Yew Tree (Taxus) Varieties by Fingerprint and Principal Component Analyses

The composition of varieties of Taxus growing in Estonia was analyzed by capillary electrophoresis with diode array detection (CE-DAD) for the separation of phenolic compounds, and by high performance liquid chromatography-mass spectrometry (HPLC-MS) for the determination of taxoids. The main purpose of this study was the chemotaxonomic differentiation of varieties of Taxus by using data from these analyses. Fingerprints scanned at 214 nm on the basis of CE separation at pH 9.3 were used to characterize seven varieties of yew. The contents of four key taxoids (10-deacetylbaccatin, baccatin III, cephalomannine and paclitaxel) in six Taxus varieties were comparatively determined by HPLC-MS. The set of electropherograms/chromatograms of the various Taxus extracts were subjected to principal component analysis (PCA), using the peak areas of 16 phenolic compounds and 14 taxoids as characteristics. The formation of distinct clusters in accordance with botanical classification proves the suitability of PCA for differentiating varieties of Taxus.

Characterization of yew tree (Taxus) varieties by fingerprint and principal component analyses

The composition of varieties of Taxus growing in Estonia was analyzed by capillary electrophoresis with diode array detection (CE-DAD) for the separation of phenolic compounds, and by high performance liquid chromatography-mass spectrometry (HPLC-MS) for the determination of taxoids. The main purpose of this study was the chemotaxonomic differentiation of varieties of Taxus by using data from these analyses. Fingerprints scanned at 214 nm on the basis of CE separation at pH 9.3 were used to characterize seven varieties of yew. The contents of four key taxoids (10-deacetylbaccatin, baccatin III, cephalomannine and paclitaxel) in six Taxus varieties were comparatively determined by HPLC-MS. The set of electropherograms/chromatograms of the various Taxus extracts were subjected to principal component analysis (PCA), using the peak areas of 16 phenolic compounds and 14 taxoids as characteristics. The formation of distinct clusters in accordance with botanical classification proves the suitability of PCA for differentiating varieties of Taxus.

Aqueous photocatalytic oxidation of sulfamethizole

Aqueous photocatalytic oxidation (PCO) of a non-biodegradable sulphonamide antibiotic sulfamethizole was studied. The impacts of photocatalyst dose, initial pH, and substrate concentration in the range from 1 to 100 mg L(-1) were examined with a number of organic and inorganic by-products determined, suggesting the initial break-up of the SMZ molecule at the sulphonamide bond. The experiments were carried out under artificial near-UV and visible light, and solar radiation using Degussa P25 and less efficient visible light-sensitive C-doped titanium dioxide as photocatalysts.

Nonaqueous CE using contactless conductivity detection and ionic liquids as BGEs in ACN

N,N'-Alkylmethylimidazolium cations have been separated in NACE when one of the N,N'-dialkylimidazolium salts (ionic liquids (ILs)) was used as an electrolyte additive to the organic solvent separation medium. The separated species were 1-methyl-, 1-ethyl-, 1-butyl-, 1-octyl-, 1-decyl-3-methylimidazolium and N-butyl-3-methylpyridinium cations and BGE composed of 1-ethyl-3-methylimidazolium ethylsulfate or 1-butyl-3-methylimidazolium trifluoroacetate [BMIm][FAcO] (A6; B2) diluted in ACN. It was demonstrated that contactless conductivity detection (CCD) may be applied to monitoring the separation process in nonaqueous separation media, allowing to use the UV light-absorbing imidazolium-based electrolyte additives. There could be marked three concentration regions of added ILs; at first ionic strength of BGE below 1-2 mM, and then the actual electrophoretic mobility of analytes rises from 0. At concentrations above 1-2 mM, the added IL facilitated separation. In concentration region of 1-20 mM, the actual electrophoretic mobility of analyzed imidazolium cations was increasing with decrease in separation medium ionic strength. At higher concentrations of BGE (above 30 mM), the conductivity of the separation media became too high for this detector. Some organic dyes were also successfully separated and detected by contactless conductivity detector in a 20 mM A6 separation electrolyte in ACN.

Capillary zone electrophoresis on chemically bonded imidazolium based salts

In the present paper, fused-silica capillaries were chemically modified with an analogue of the imidazole-based ionic liquid and zwitterionic salt. The coated capillaries were examined for the behavior of the electroosmotic flow in both aqueous and non-aqueous electrolytes. The electroosmotic flow in the capillary coated with an ionic liquid analogue was found to be anodic (reversed) and dependent on the pH of the separation buffer. In the case of a zwitterionic capillary, the electroosmotic flow was cathodic and its velocity remained almost constant in the pH range of 4-7. The zeta-potentials of the modified surfaces were also calculated. The effectiveness of coating was investigated by comparing a separation of five inorganic ions and seven alkylphosphonic acids/monoesters in the modified and uncoated capillaries. All separations were successfully carried out in simple buffers and completed during a short analysis time. Finally, the run-to-run and day-to-day reproducibility of the coated capillaries in terms of the migration time of a neutral marker was determined.

Large outbreak of acute gastroenteritis in Samokov Region, Bulgaria, February 2007

In the beginning of February 2007, a marked increase in the number of cases of acute gastroenteritis in Samokov, a region in western Bulgaria, south of the capital Sofia, was noted by the Regional Inspectorate for Public Health Protection and Control.