Chromatographic Behaviour of Antibiotics on Thin Layers of Zeolite

Introduction: Antibiotics analysis is performed by many methods such as spectrophotometry, fluorimetry, polarography, and high-performance liquid chromatography. This analysis doesn't require derivatization but requires expensive equipment and extensive preparation. When more than one antibiotic is present in a formulation, interactions may occur between the drugs that must be separated before measurement. Thin-layer chromatography is a useful technique for identifying antibiotics because of the low cost, high speed, and low servicing. Silica gel adsorbents have often been used as adsorbents in all thin-layer chromatography studies. In this study, zeolite was used as an adsorbent in thin- layer chromatography with high selectivity. Materials and Methods: The chromatographic behaviour of amoxicillin, ampicillin, cefazolin, cefixime, ceftriaxone, cefalexin, and penicillin was studied for the first time on a thin layer of zeolite with mobile, organic, and organic- organic phases. Discussion: The best separation of ceftriaxone from amoxicillin, ampicillin, cefazolin, cefixolin, cefalexin, and penicillin on a thin layer of zeolite using methanol as the mobile phase. The distance and rise time are 12 cm and 110 minutes, respectively. Conclusion: The results of the present study showed that using the current method, the selectivity of one antibiotic from other components as well as two-component andthree-component adsorption was obtained. Quantitative identification of antibiotics was also performed in multicomponent mixtures after selection of appropriate isolates.

Liquid chromatographic studies on the behaviour of Pu(III), Pu(IV) and Pu(VI) on a RP stationary phase in presence of α-Hydroxyisobutyric acid as a chelating agent

Since plutonium possesses multiple oxidation states which can coexist in solution, a method for the identification of these oxidation states is important to understand its chemical processes. Liquid chromatographic studies were carried out to compare the chromatographic behaviour of different oxidation states of Pu in presence of the eluent, α-hydroxyisobutyric acid (HIBA). The three oxidation states of Pu viz. Pu(III), Pu(IV) and Pu(VI) were separated under optimised conditions. It was seen that the presence of the complexing agent influences the equilibrium of Pu(III)/(IV) as well as Pu(IV)/(VI) systems. Pu(III) to Pu(IV) conversion was found to be enhanced by high pH and concentration of HIBA whereas a relatively low pH and high concentration of HIBA promotes the conversion of Pu(VI) to Pu(IV).

Sliding Motility, Biofilm Formation, and Glycopeptidolipid Production inMycobacterium colombienseStrains

Mycobacterium colombienseis a novel member of theMycobacterium aviumcomplex, which produces respiratory and disseminated infections in immunosuppressed patients. Currently, the morphological and genetic bases underlying the phenotypic features ofM. colombiensestrains remain unknown. In the present study, we demonstrated thatM. colombiensestrains displaying smooth morphology show increased biofilm formation on hydrophobic surfaces and sliding on motility plates. Thin-layer chromatography experiments showed thatM. colombiensestrains displaying smooth colonies produce large amounts of glycolipids with a chromatographic behaviour similar to that of the glycopeptidolipids (GPLs) ofM. avium. Conversely, we observed a natural rough variant ofM. colombiense(57B strain) lacking pigmentation and exhibiting impaired sliding, biofilm formation, and GPL production. Bioinformatics analyses revealed a gene cluster that is likely involved in GPL biosynthesis inM. colombienseCECT 3035. RT-qPCR experiments showed that motile culture conditions activate the transcription of genes possibly involved in key enzymatic activities of GPL biosynthesis.