Authors:M.A. Hawrył, M. Niemiec, K. Słomka, M. Waksmundzka-Hajnos, and G. Szymczak
Micro-thin-layer chromatography in two dimensional (2D-mTLC) mode in normal and reversed phase systems by use of diol bonded stationary phase was applied to make fingerprints of 11 species of Mentha genus and two finished pharmaceutical products.
Nonaqueous eluents (propan-2-ol or ethyl acetate dissolved in n-heptane) were used in normal phase systems. Mixtures of acetonitrile with water were used in reversed phase chromatographic systems.
Optimization of one dimensional systems was performed by determining of RF vs. composition of mobile phases dependencies for standards occurring in various species of Mentha. Most selective eluents were chosen to optimize two-dimensional systems by creating RF in normal-phase (NP) systems vs. RF in reversed-phase (RP) systems correlations.
2D-mTLC on diol polar bonded stationary phase were optimized to separate phenolic compounds and make fingerprints of examined plant materials and this method was never applied earlier in the chromatographic analysis.
-molecular-mass glycol or diol which serve as glycolysis agents. Usually, the catalysts are used, and in some cases, amines are added which results in aminoglycolysis. The products of glycolysis are the so-called glycolysates, which consist of a homogenous mix of various
Authors:K. Wróblewski, A. Petruczynik, and M. Waksmundzka-Hajnos
Psychotropic drugs: desipramine, olanzapine and mitrazapine were chromatographed on cyanopropyl-silica and Diol-silica thin layers using various nonaqueous and aqueous eluents.
The best results were obtained with addition of ammonia to nonaqueous eluent on both adsorbents. On the basis of the optimization, systems for extraction from human plasma and quantitative determination of investigated drugs were selected.
RP18 encaped SPE columns conditioned and pre-eluted with acetonitrile:water:ammonium buffer at pH 8.6 (5:5:2) and eluted with methanol:water (9:1) containing 2% acetic acid were used for sample preparation with high recoveries of all investigated drugs. Diol and CN plates with mixture of 15% methanol in diisopropyl ether + 1% ammonia were used for quantitative analysis by a calibration curve method.
Authors:M. Daszykowski, M. Hawrył, M. Waksmundzka-Hajnos, and B. Walczak
In this paper a broad overview of the retention behaviour of twenty flavonoids and their analogues in 74 TLC systems is reported. The compounds were chromatographed on different stationary phases (non-polar and polar-bonded stationary phases — wettable RP18W, silica, and aminopropyl-modified and diol-modified plates) developed with a variety of binary mobile phases (aqueous and non-aqueous). The chemometric techniques principal component analysis and hierarchical clustering were used to evaluate similarities and differences among the chromatographic systems. For selection of the most suitable systems either to perform two-dimensional separation or to enhance overall resolution by merging two stationary phases, indices scoring the separating power of a given system or pair of systems were applied. When separation of all pairs of chromatographic systems was evaluated with the index considered, the theoretical separation achieved in these systems could be visualized as a colour map. This colour map enabled rapid examination of resolution and selection of orthogonal systems enabling acceptable separation of the compounds. On the basis of the colour map it was found that relatively efficient two-dimensional separation of the compounds could be achieved on amino-modified plates developed using 9:1 tetrahydrofuran-water in the first dimension then 9:1, 4:1, 3:1, or 7:3 acetonitrile-water in the second dimension. Theoretically, the best separation could be achieved by combining diol-modified and amino-modified stationary phases and using 3:2 methanol-water and 9:1 acetonitrile-water, respectively, as mobile phases.
– 14] . Methanol solutions in some respects show similar properties to those of aqueous solutions and in others they resemble DMF solutions. Recently, we have turned our attention to systems containing a diol as a non-electrolyte. The wide applications
different sizes (from 3–4 to 15°μm).
The main products of the process of allylic compound epoxidation are epoxide compounds. Depending on the conditions, the following compounds are also formed: diols—the products of epoxide ring hydration, ethers
Authors:E. Keppelné Bognár, K. Zay, and L. Somogyi
fatty acid esters in edible oils and fats (in this study we examined only 3-MCPD-FE). The method is based on alkaline-catalyzed ester cleavage, and derivatisation of free diols with PBA. These derivatives were measured in splitless mode by GC/MS coupled
Authors:Bao-xia Fang, Lin-hai Wang, Fu-chao Chen, Peng Li, and Xiao-ya Shi
Butorphanol tartrate ( Figure 1 a) is a mixed agonist–antagonist opioid with strong κ-receptor agonist and weak μ-receptor antagonist activity. Chemically, it is morphinan-3,14-diol,17-(cyclobutylmethyl
Authors:Jerzy J. Chruściel, Grażyna Janowska, and Marzena Fejdyś
successfully used as halogen-free fire retardants. Ammonium polyphosphate, microencapsulated with a low molecular weight polydimethylsiloxane-α,ω-diol, showed enhanced water resistance and significantly improved flame resistance properties as compared with an