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Uranyl ion-imprinted polymeric (IIP) resins were prepared by dissolving stoichiometric amounts of uranyl nitrate and selected chelating ligands, viz. salicylaldoxime, catechol, succinicacid, 5,7-dichloroquinoline-8-ol and 4-vinyl pyridine in 2-methoxy ethanol (porogen) and copolymerizing thermally in the presence of 2-hydroxyethylmethacrylate (HEMA) and ethyleneglycol-dimethacrylate (EGDMA), using 2,2'-azobisisobutyronitrile (initiator). Again, IIP resins were also prepared on similar lines by utilizing ternary [uranium-non-vinylated ligand-vinylated ligand (4-vinyl pyridine)] complexes. Non-imprinted polymeric resins were identically prepared in both cases without the use of uranyl imprint ion. The percent enrichment and retention capacity studies showed significant imprinting effect in all cases. However, ion-imprinted polymeric resins formed with succinic acid (SA) or 5,7-dichloroquinoline-8-ol (DCQ) and 4-vinylpyridine (VP) alone gave quantitative enrichment and various parameters that influence the enrichment and elution were then optimized. The percent enrichment of uranium from synthetic seawater solutions was found to be 25.0+/-0.5 and 83.0+/-0.8 for SA-VP and DCQ-VP systems, respectively. The DCQ-VP-based IIP resins were successfully tested for the recovery of uranium from real seawater samples.

The chemical speciation of dissolved copper in a coastal seawater sample was determined using a variety of voltammetric methods by three different research groups. This intercomparison study was performed on a sample from near the mouth of Narragansett Bay, Rhode Island, chosen to be representative of coastal seawater from the East Coast of North America. Three research groups used distinct methods of competitive ligand equilibration/adsorptive cathodic stripping voltammetry (CLE-ACSV) with different competing ligands (salicylaldoxime, benzoylacetone and 8-hydroxyquinoline), two of which employed a range of added ligand concentrations. Two groups used anodic stripping voltammetry (ASV) with a thin mercury film (TMF) rotating glassy carbon disk electrode (RGCDE). Combining these various approaches, resulted in analytical competition strengths (αCu(AL)2) ranging from 102.7 to 106.5 for the CLE-ACSV approaches and 101.3 (αCu) for the ASV methods. As the value of the analytical competition strength for the added competing ligand increased, the value determined for the natural Cu-binding ligand concentration decreased, while its conditional stability constant, KCuLi,Cu2+cond, increased. This type of behavior is consistent with the natural Cu-binding ligands consisting of a continuum of Cu-binding ligands with increasingly smaller concentrations of increasingly stronger ligands. Results from the different approaches carried out at similar analytical competition strengths compared very favorably. All of the approaches determined that dissolved copper in this sample was overwhelmingly chelated with strong Cu-binding ligands (>99.97%). Thus, although the total dissolved copper concentration was 12.7 nM (10−7.9 M), the Cu-binding ligands lowered the free cupric ion concentration, [Cu2+], to ∼10−13.0 M, a concentration that is non-toxic to even the most sensitive marine microorganisms.

Copper complexing ligands in sea water were determined by cathodic stripping voltammetry (CSV) with ligand competition using salicylaldoxime (SA) at a detection window intermediate to that and overlapping with those currently available using other electroactive ligands. The optimised condition to determine total dissolved copper in sea water by CSV using SA entails an SA concentration of 25 μM, a solution pH of 8.0–8.4, and a deposition potential of -1.1 V; the voltammetric scans were initiated at -0.15 V. The conditional stability constants for copper complexation by SA were calibrated by ligand competition against EDTA in sea water of salinities between 1 and 35. The following empirical relationships were found to hold between these conditional stability constants and the salinity (S, in psu): log K′CuSA = (10.12 ± 0.03) - (0.37+-0.02) log S, and log β′Cu(SA)2 = (15.78 +- 0.08) - (0.53 +- 0.07) log S. The centre of the detection window for detection of copper complexation in sea water using SA can be varied in the range of 3.6–5.8 by varying the SA concentration between 1 and 25 μM; this range lies between that covered by tropolone (2.5–4.5) and 8-quinolinol (5.0–8.4). Use of SA in CSV has the analytical advantage of high sensitivity for copper (3–4 fold greater than using catechol, 8-quinolinol or tropolone), reflected in a limit of detection of 0.1 nM copper at a deposition time of 1 min which can be lowered further by extending the deposition time. Comparative complexing ligand titrations indicated that an equilibration period of 6 h is required to attain equilibrium between the added copper, the natural comlexing ligands and the added SA. The method was tested by determining copper complexation at several windows in samples from the North Sea, the NW Mediterranean Sea and the NE Atlantic Ocean, revealing the presence of several complexing ligands. At a constant detection window the ligand concentration in the upper water column of a station in the NE Atlantic was found to vary between 3 and 8 nM, with a maximum at 78 m depth.

Ion-imprinted polymers (IIPs) were prepared for uranyl ion (imprint ion) by formation of binary (salicylaldoxime (SALO) or 4-vinylpyridine (VP)) or ternary (salicylaldoxime and 4-vinylpyridine) complex in 2-methoxy ethanol (porogen) following copolymerization with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinking monomer using 2,2'-azobisisobutyronitrile as initiator. Control polymers (CPs) were also prepared under identical experimental conditions without using imprint ion. The above synthesized polymers were characterized by surface area measurement, microanalysis and FT-IR analysis techniques. The imprinted polymer formed with ternary complex of UO(2)(2+)-SALO-VP (1:2:2, IIP3) showed quantitative enrichment of uranyl ion from dilute aqueous solution and hence was chosen for detailed studies. The optimal pH for quantitative enrichment is 3.5-6.5. The adsorbed UO(2)(2+) was completely eluted with 10 mL of 1.0 M HCl. The retention capacity of IIP3 was found to be 0.559 mmol g(-1). Further, the distribution ratio and selectivity coefficients of uranium and other selected inorganic ions were also evaluated. Five replicate determinations of 25 microg L(-1) of uranium(VI) gave a mean absorbance of 0.032 with a relative standard deviation of 2.20%. The detection limit corresponding to three times the standard deviation of the blank was found to be 5 microg L(-1). IIP3 was tested for preconcentration of uranium(VI) from ground, river and sea water samples.

Vanadium(V) reacts with monobasic and bidentate extracting agents, i.e. 8-quinolinol, 2-methyl-8-quinolinol, salicylaldoxime, hinokitiol, benzoylphenylhydroxylamine, maltol, cupferron, dibenzoylmethane, salicylaldehyde, and phenylmethylbenzoylpyrazolone-5, to form 1:2 complexes containing a basic V=O group and an acidic V—OH group in the same molecule. The basic group reacts with acidic substances to give a hyper- and bathochromic effect; the acidic group reacts with basic substances to give a hyper- and hypsochromic effect. These reactions are observed in benzene solutions.

The model of thin-layer chromatography suggested earlier has been developed so that it describes solute behaviour more thoroughly. Equations have been derived which describe particular cases such as development by a single solvent, or by a mixture of two solvents of different polarity, or by a mixed solvent of constant composition at varying humidity. Experimental verification was provided by a study of the t.l.c. behaviour of metal dithizonates and diethyldi-thiocarbamates on Silufol. A comparison of the mobilities of these metal chelates, as well as of those of 8-hydroxyquinoline, salicylaldoxime and benzoylacetone, with their extraction constants showed a mutual correlation between these properties.

It has been found that the innercomplex salts of palladium with dimethylglyoxime, (benzildioxime and furildioxime), salicylaldoxime and 8-hydroxyquinolinc do not enter into redox reaction with carbon monoxide, cither in solid or in molecular dispersed form. Solutions of palladium-dimethylglyoxime and palladium-salicylaldoxime in alkali hydroxide or ammonia are masked with respect to many reactions of the palladium as well as of the organic components. In alkaline solutions, when adding alkali cyanide, demasking occurs, with the deliberation of the innercomplex forming organic components. For the processes of dissolution and demasking appropriated equations are suggested. The demasking of dimethylglyoximc in alkaline solutions of palladium dimethylglyoxime permits a new sensitive test for cyanide ion. This cyanide test seems to be appropriate for the detection of illuminating gas. Palladium hydroxyquinorate is insoluble in solutions of alkali cyanides, though it is not precipitable from cyanide containing palladium solutions. An explanation for this “false equilibrium” is suggested.

A highly sensitive spectrophotometric method for the determination of traces of copper with 2-(5-nitro-2-pyridylazo)-l-naphthol (5N-α-PAN) has been developed. At a pH of 3–4copper(II) is selectively extracted into chloroform as its salicylaldoxime chelate and then stripped into an aqueous acid solution; the pH is adjusted to 9.3, and 5N-α-PAN is added. The 1:2 chelate between copper(II) and the reagent, which promptly precipitates, is extracted into chloroform and measured at 598 nm. The molar absorptivity is 86,000. The application of the method to the analysis of high-purity magnesium and cobalt is described.

Solvent extraction methods were used to prepare the solutions of the palladium and rhodium chelates that were investigated. Toluene, chloroform, 4-methyl-2-pentanone, and pentyl acetate were used as extraction solvents. The effectiveness of several different chelating agents for palladium and for rhodium was investigated. The optimum pH was determined for each of the extraction systems that was used. The extraction of the salicylaldoxime chelate of palladium into 4-methyl-2-pentanone was found to be quantitative at pH 3. The chelate of rhodium produced by sodium diethyldithiocarbamate was completely extracted into 4-methyl-2-pentanone at pH 8.

Traces of copper can be extracted and determined spectrophotometrically by means of thiodibenzoylmethane. The determination is highly selective, with a molar absorptivity of 23.7·103 at 410 nm. There is no interference from 1000-fold amounts of Na, K, Ca, Mg, Sr, B, Al, Ga, In, Tl, Pb, Co, Ni, Mn, ammonia, citrate, tartrate, or salicylaldoxime; from 100-fold amounts of Fe, Zn, Cd, Bi, Hg, Ag, Sb, Cr, thiourea, or thioglycolic acid; or from 10000-fold amounts of iodide, fluoride, thiocyanate or nitrate. Cyanide or palladium in equal amounts interfere.