Flavonoid compounds possessing vitamin P activity, such as quercetin and quercetin-3-O-rhamnoglucoside (rutin), are usually produced for the vitamin industry by extraction from various raw plant materials [ 1,2]. As is known, the extraction, purification, and analysis of the above flavonoids are frequently performed by liquid chromatography using colunms filled with polyamide (PA) sorbents [3 -12]. However, neither types of PA sorbents nor their characteristics are usially indicated in most of the domestic publications, in contrast to the papers published abroad. This circumstance reflects the absence of standard domestic PA sorbents for the column chromatography, which accounts for the use of various laboratory methods in the preparation of sorbents. As a result, the data reported by different authors are difficult to compare.The purpose of this work was to obtain PA sorbents and characterize their partitioning ability for the liquid chromatography of flavonoid compounds with vitamin P activity.
EXPERIMENTAL PARTThe PA sorbents were prepared from commercially available domestic granulated raw materials: polycaprolactam PA-6 (Standard Technological Conditions TU 6-05-988-98) and poly(hexamethylene sebacamide) PA-610 (State Standard GOST 10589-73) produced by the Sverdlovsk Plastics Plant. The PA powders were obtained by precipitation from 30% hydrochloric acid solutions of the above raw materials with a 6-fold excess of an ethanol -water (1 : I) mixture under intense stirring at room temperature. The precipitate was filtered, washed to neutral pH reaction with water and ethanol, and slightly dried in air. Then the product in the slightly wet state was separated into fractions by sieving. Further tests were performed with fractions having grain size within 0. I -0.2 mm. The powders obtained from PA-6 and PA-610 were characterized by a water absorption of 10.5 and 3.1% (upon a i "Reaktiv" State Engineering Center, Ufa, Bashkortostan, Russia. 2 Institute of Biology, Ufa Scientific Center, Russian Academy of Sciences, Ufa, Bashkortostan, Russia.
38110-day exposure over water) and a molecular weight of 20,300 and 14,200, respectively. The water absorption was studied by a standard procedure according to which a powder sample is weighed upon keeping in a desiccator over water, and the molecular weights were determined by viscometry [13]. Thje intrinsic viscosity of PA-6 was determined in a mixture of formic acid with water (64.5 : 35.5) at 25~ and that of PA-610, in toluene at 44~ The partitioning ability of the final PA powders having the characteristics indicated above was studied using artificial mixtures of quercetin, isoquercitrin, and rutin-a combination of flavonoids that is frequently present in raw plant materials [14]. The experiments were performed with commercial quercetin (Lachema, Brno, Czech Republic), rutin (Olaine Chemico-Pharmaceutical Plant, Olaine, Latvia), and isoquercitrin obtained by preparative column chromatography under laboratory conditions. The partitioning experiments were conducted in a la...