Stability of the 13C column separation in industrial mode of operation
Based on the original cryogenic column conceived and built by National Institute for Research and Development of Isotopic and Molecular Technologies Cluj-Napoca, it is necessary to implement control algorithms for the industrial mode of operation of this equipment, in order to produce some chemical compounds with higher concentration in (13C), compounds asked in various domains. The present work deals with column efficiency analysis and stability in industrial mode of operation.
Flooding process analysis by 13C cryogenic separation column
The applications of stable isotopes from different chemical elements are well-known. Based on specific properties, a great diversity of isotope concentration (separation) methods have been developed, one of them being the cryogenic separation for (13C). After a short description of the separation equipment (separation column), the authors deal with the arising of the flooding process. Based on simplified equations, the evolution of an intended flooding is studied, divided in more stages: normal mode of operation, pre-flooding, ldquodischargerdquo period, flooding period and flooding damping. The next step of study will analyze the possibilities to avoid the flooding process.
HPLC determination of chlorhexidine gluconate and p-chloroaniline in topical ointment.
A novel fast isocratic reversed-phase HPLC method for simultaneous determination of chlorhexidine and its degradation product p-chloroaniline was developed. Zorbax SB Phenyl column (75 mm x 4.6 mm, 3.5 microm) was used for the separation. Mobile phase composed of acetonitrile and buffer solution of 0.08 M sodium phosphate monobasic containing 5 ml of triethylamine (0.5%) and adjust with 85% phosphoric acid to pH 3.0 in ratio 35:65 (v/v) pumped isocratically at flow rate 0.6 ml min(-1) was used. UV detection was performed at 239 nm, the total analysis time was about 10 min. The method is suitable for practical routine analysis of topical ointment in the quality control laboratory.