Suspension column for recovery and separation of substances using ultrasound-assisted retention of bead sorbents.

A novel approach to sorption recovery and separation of different substances is proposed which is based on the use of suspended bead sorbents instead of conventional packed beds of such sorbents. This makes it possible to employ small-sized beads which are trapped in a low-pressure column due to ultrasound-assisted retention, without any frits to hold the sorption material. A flow system including a separation mini-column, named herein a suspension column, has been developed and tested by the studies of solid phase extraction (SPE) of trace metals from bi-distilled water and sea water using a 150-µL column with a silica-based sorbent containing iminodiacetic groups (DIAPAK IDA) and having a grain size of 6 µm. The adsorption properties of DIAPAK IDA suspension (9.5mg) were evaluated through adsorption/desorption experiments, where the effect of solution pH and eluent on the SPE of trace metals were examined by ICP-MS or ICP-AES measurements. When sample solution was adjusted to pH 8.0 and 1 mol L(-1) nitric acid was used as eluent, very good recoveries of more than 90% were obtained for a number of elements in a single-step extraction. To demonstrate the versatility of the approach proposed and to show another advantage of ultrasonic field (acceleration of sorbate/sorbent interaction), a similar system was used for heterogeneous immunoassays of some antigens in ultrasonic field using agarose sorbents modified by corresponding antibodies. It has been shown that immunoglobulins, chlamidia, and brucellos bacteria can be quantitatively adsorbed on 15-µm sorbent (15 particles in 50 µL) and directly determined in a 50-µL mini-chamber using fluorescence detection.

Theoretical and experimental investigation of immunoprecipitation pattern formation in gel medium.

We present the results of our comprehensive study of precipitation pattern formation by interacting immunogenic proteins in a gel medium. Formation of immunoprecipitation patterns was studied both theoretically and experimentally. Based on a system of reaction-diffusion equations, continuous deterministic description provides a quantitative model of reaction kinetics. Discrete stochastic microscopic description was used to supplement the results of reaction-diffusion model by mimicking product aggregation that contributes to a deeper understanding of the mechanism that governs the phenomenon. Our studies have shown that the mechanism of immunoprecipitation pattern formation is specific for protein precipitation and differs from such mechanisms for any inorganic or biological substances. By microscopic examination, we demonstrated that immunoprecipitation patterns can have a microstructure. We found that the microscopic structure of immunoprecipitation patterns results from multicomponent composition of antiserum.