A procedure was proposed for the preconcentration of Sr, Cs, Pb, Co, Bi, and Ce beta radionuclides by solid-phase extraction as ion-pair complexes in the system dicyclohexyl-18-crown-6–sodium dodecyl sulfonate.

Recovery of Eu(III) and Am(III) by solid-phase extraction in the form of complexes with tetraphenylmethylenediphosphine dioxide (TPMDPD) was studied. TPMDPD is suitable for concentrating these elements from nitric acid solutions in the acidity range from pH 5 to HNO3 concentration of 6 M. High degree of recovery (concentrating factors 10(2)-10(3)) is preserved in extraction from large volumes of solutions and at a high solution flow rate. The recovery from nitric, hydrochloric, sulfuric, and phosphoric acid solutions increases on adding minor amounts of perchloric acid. The recovery is selective: Na, K, Ca, Mg and Al present in concentrations of 2, 1, 10(-1) 10(-2), and 10(-4) M, respectively, do not interfere with extraction from 3 M HNO3, and the same elements present in concentrations of 1, 0.5, 10(-3), 10(-3), and 10(-3) M, respectively, do not interfere with extraction from solutions with pH 5.

A procedure for determining antimony and arsenic in-fresh water, plants, and common salt was developed. The procedure is based on the selective preconcentration of Sb(III) and As(III) dipropyl dithiophosphates from chloride solutions by solid-phase extraction using DIAPAK-C16 cartridges. It is shown that microcolumns with this sorbent can be used for flow preconcentrating antimony and arsenic. Antimony and arsenic are determined in the eluate by electrothermal atomic absorption spectrometry. The relative standard deviation in the determination of antimony and arsenic at the level of 10(-6) to 10(-4)% is 3-7%.

Recovery of Eu(III) and Am(III) by solid-phase extraction in systems with diaryl(dialkylcarbamoylmethyl)phosphine oxides (CMPOs) was studied. CMPOs can be can be successfully used for concentration of these elements from nitric acid solutions. The degree of recovery from nitric, hydrochloric, and sulfuric acid solutions increases in the presence of minor amounts of perchloric acid. The Na, K, Ca, Mg, and Al ions in concentrations up to 0.1 M do not interfere with the recovery. The interfering effect of Fe(III) can be eliminated by adding hydroxyethylidenediphosphonic acid.

The behavior of palladium, platinum, iridium, and gold was studied when platinum-group metals are extracted by solid-phase extraction as ion pairs of anionic platinum-metal chloride complexes and tetrabutylammonium and as chelates of dialkyldithiophosphoric acids. These systems were shown to be suitable for the preconcentration of the studied elements.

It was demonstrated that the data on liquid-liquid extraction of neutral metal chelates can be used for choosing the optimum chelating reagents and conditions for the recovery of metals by solid-phase extraction.