Zapis posveta o zahtevah po znanju slovenščine, kot jih opredeljuje najnovejši Zakon o tujcih, in dostopu do znanja slovenščine za državljanke in državljane tretjih držav. Javni posvet je organiziral ...Center za slovenščino kot drugi in tuji jezik Filozofske fakultete Univerze v Ljubljani in se je odvil v torek, 9. maja 2023, v Zbornični dvorani Univerze v Ljubljani.
A novel and simple method has been developed for the determination of doxycycline (DOX) in biological fluids. The method is based on SPE, large-volume sample stacking (LVSS) and MEKC with UV-DAD ...detection. Six SPE cartridges have been used in investigation for sample clean up and pre-concentration (Supelco® LC-8, LC-18, LC-SCX, and LC-WCX, as well as Stratatrade mark sign-X and X-C). DOX was determined on a 56 cm (effective length 50 cm)x50 μm id fused-silica capillary. The BGE was 20 mM borate buffer, pH 9.3, containing 80 mM SDS and 7.5% v/v of methanol (30 sx50 mbar), and the temperature and voltage were 25°C and 30 kV, respectively. The analytical wavelength was set at 210 nm. Under optimized conditions it is possible to determine DOX in human serum, urine, semen, tears and saliva with recovery of 97.5% (RSD 2.5%). The method was shown to be sensitive (LOD is 1 μg/L) and precise (intra-day RSD 0.2 and 2.4%; inter-days 0.4 and 3.5% for migration time and peak area, respectively). Results for developed SPE-LVSS-MEKC were compared with LVSS-MEKC method with direct sample injection. The new LVSS-MEKC method is presented as a useful technique for rapid determination without extraction procedure of DOX in human urine and serum, using 80 mM of SDS, 10% v/v of methanol and 40 mM borate buffer (pH 9.3; 30 sx50 mbar; 25°C; 30 kV; 350 nm), but not for the other biological fluids, according to lower sensitivity of the method and because of the sample composition.
Micellar electrokinetic capillary chromatography (MEKC) has become a popular mode among the several capillary electro-migration techniques. Most drug analysis can be performed by using MEKC because ...of its wide applicability. Separation of very complex mixtures, determination of drugs in the biological materials, etc., can be successfully achieved by MEKC. This review surveys typical applications of MEKC analysis. Recent advances in MEKC, especially with solid-phase extraction and large-volume sample stacking, are described. Modes of electrokinetic chromatography including MEKC, a separation theory of MEKC, environmental friendly analysis, and selectivity manipulation in MEKC are also briefly mentioned.
Micelama elektrokineticka kapilarna hromatografija (MEKC) postala je najpopularnija kapilarna elektromigraciona metoda. Na osnovu veoma siroke upotrebe metode, vecina analiza lekova moguca je uz MEKC. Separacija veoma kompleksnih smesa, odredjivanje lekova u bioloskom materijalu, i analize drugih uzoraka, mogu biti veoma uspesno izvedene upotrebom MEKC tehnike. U okviru ovog preglednog rada prikazana je aplikacija tipicnih MEKC metoda. Noviji pristupi u kombinaciji sa cvrsto-faznom ekstrakcijom i visoko-volumskim injektovanjem su takodje opisani. Teorijski i ekoloski pristup, kao i prednosti i nedostatci same metode, prikazani su teorijski i kroz prakticne primere.
A method is described for quantitating caffeine, theobromine, theophylline, paracetamol, propyphenazone, acetylsalicylic acid, salicylic acid, and codeine phosphate in corresponding real samples of ...food, beverages, natural products, pharmaceuticals, and cosmetic preparations by micellar electrokinetic capillary chromatography. The separation is carried out at 25°C and 25 kV, using a 20mM phosphate buffer (pH 9.0), 80mM sodium dodecyl sulfate, and 7.5% (v/v) acetonitrile. UV detection is at 210 nm. The method is shown to be specific, accurate (recoveries over the range 98.9–101.2%), linear over the tested range (correlation coefficients ≥ 0.9993), and precise (relative standard deviation below 2.1%). The method is applied for the quantitative analysis of these compounds in different foods, beverages, natural products, pharmaceuticals, and cosmetic products.
A separation technique for zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide in animal feedstuffs by micellar electrokinetic capillary chromatography (MEKC) was developed. The running ...buffer was 20 mmol l
−1
borate, 20 mmol l
−1
phosphate, pH 8.4, containing 20 mmol l
−1
sodium dodecylsulphate and 10% (v/v) methanol. MEKC was performed at 25°C; the applied voltage was 25 kV with a running pressure of 10 mbar. Simultaneous UV detection for all analytes was at 215 nm. The method was validated for specificity, accuracy, linearity, precision and robustness. It was shown to be specific, accurate (recoveries were 99.7 ± 0.3, 99.9 ± 0.9, 99.8 ± 1.0 and 99.5 ± 0.4, respectively, for oxytetracycline-, sulfacetamide-, polymyxin B- and zinc bacitracin-spiked samples of feed for cow, pigs, chicken and cattle), linear over the tested range (correlation coefficients ≥0.9987) and precise (RSDs below 1.8% for each analyte). The method was applied to determine zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide as additives in animal feed.
BACKGROUND: The European Union has forbidden the use of antibiotics as additives in animal feed. Zn-bacitracin (Zn-BC) and nystatin (NYS) were frequently used for their growth-promoting effects and ...for feed conversion in poultry, pigs and cattle. An HPTLC method has been developed for separating Zn-BC and NYS in the mixture, for routine quality control.RESULTS: The separation was obtained using RP-18 F₂₅₄S coated HPTLC plates with acetonitrile/methanol (equal volumes):toluene:KH₂PO₄/KOH (buffer, pH 6.8) = 57:3:40 (v/v/v), adjusted with HCl to pH 8.2, as a mobile phase. The densitograms were monitored at 192, 215 and 305 nm and both antibiotics were assayed at 215 nm. The method was shown to be specific, accurate (recoveries were 98.7 ± 0.5% and 104.8 ± 0.7% for Zn-BC and NYS, respectively), linear over the tested range (correlation coefficients, 0.9982 and 0.9884), and precise (intermediate precision RSD below 2.2% for both analytes) with efficient separation (Rs = 3.5).CONCLUSION: The method was applied for determining Zn-BC and NYS as additives in spiked matrices of commercial animal feedstuffs. According to LOD values for each antibiotic, the minimum detectable amount in feed is 4.5 and 5.5 ppm of Zn-BC and NYS, respectively. Copyright
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