Flow-injection preconcentration and graphite furnace atomic absorption spectrometric determination of platinum.

Flow-injection graphite furnace atomic absorption spectrometric (GFAAS) methods were worked out using oxime, sulphoxine and 2,2'-diamino-diethylamine (DEN) cellulose microcolumns for preconcentration of platinum after reduction by iodide or sulphite ions. The detection limits were, at 20-fold enrichment, 0.21, 0.18 and 0.30 mug l(-1), respectively. The total reflection X-ray fluorescence spectrometry (TXRF) was also used for the determination of platinum in eluates. The method was applied for the determination of platinum in salmeterol xinafoate and Ca-folinate pharmaceutical compounds. Decomposition of organic matrix of Ca-folinate was necessary before the preconcentration.

Use of a new type of 8-hydroxyquinoline-5-sulphonic acid cellulose (sulphoxine cellulose) for the preconcentration of trace metals from highly mineralised water prior their GFAAS determination.

Sulphoxine cellulose microcolumn was used in an FI-GFAAS system for the preconcentration of trace metals, Cd, Co, Ni, Pb and V from water and from highly mineralised water and also in the presence of complexing agent, e.g. citrate. The recovery was quantitative at pH 5 for all of the elements from NIST 1643c trace elements in water SRM and from highly mineralised water samples. No significant difference was found in the sorption of V(IV) and V(V) during preconcentration. The preparation of the 8-hydroxyquinoline-5-sulphonic acid cellulose (sulphoxine-cellulose) by Mannich reaction from aminoethyl cellulose or via chlorodeoxy and ethylenediamine cellulose is also described.

Optimization of Flow Injection On-Line Microcolumn Preconcentration of Ultratrace Elements in Environmental Samples prior to Their Spectrochemical Determination

The preconcentration of some elements such as Cd, Co, Ni, and V(IV) was modeled in the presence of complexing agents such as citrate and oxalate at high Ca, Mg, and sulfate concentrations on iminodiacetic acid/ethyl cellulose (IDAEC), a chelating cellulose. The effect of the species present in the solution was studied after construction of the species distribution curves using critical, estimated, and measured stability constants. The stability constants of the IDAEC chelates were determined potentiometrically. The constants were calculated or estimated using computer programs. The diagrams calculated in homogeneous media were used for optimization of the flow injection on-line preconcentration for analysis of ultratrace metals in the highly mineralized water "Hunyadi."

How much soil do young children ingest: an epidemiologic study.

Sixty-four children aged 1-4 years were evaluated for the extent to which they ingest soil. The study followed the soil tracer methodology of S. Binder, D. Sokal, and D. Maughan (1986, Arch. Environ. Health, 41, 341-345). However, the present study included a number of modifications from the Binder et al. study. The principal new features were (1) increasing the tracer elements from three to eight; (2) using a mass-balance approach so that the contribution of food and medicine ingestion would be considered; (3) extending the period of observation from 3 days to 8 days; and (4) validating the methodology by having adult volunteers ingest known amounts of soil in a mass-balance validation study. The principal findings reveal the following. (1) The adult study confirmed the validity of the tracer methodology to estimate soil ingestion. (2) Of the eight tracers employed in the adult study, only Al, Si, and Y provided sufficient recovery data that was directly acceptably stable and reliable. (3) If food ingestion determinations were taken into consideration, the median estimates of soil ingestion from the eight tracers ranged from a low of 9 mg/day (Y) to a high of 96 mg/day (V); the median values of Al, Si, and Y, the three most reliable tracers, ranged from 9 mg/day to 40 mg/day. (4) One child had soil ingestion values ranging from 5 to 8 g/day, depending on the tracer. (5) If food ingestion had not been considered, the estimates of soil ingestion would have increased about two- to sixfold, depending on the tracer with Ti and Y being most affected by food intake. (6) Since soil and dust samples did not significantly differ in their levels of tracer elements, no reliable differentiation between the contribution of ingestion of dust and soil could be made. (7) These findings are generally consistent with the previously reported findings of Binder et al. (1986) and P. Clausing, B. Brunekreff, and J.H. van Wijnen (1987, Int. Arch. Occup. Med., 59, 73) if these latter studies are corrected for ingestion of tracers in food and medicine. The findings also account for the apparent discrepancy between the estimates from Al and Si and estimates based on Ti in previous studies. Thus the elevated estimates of soil ingestion by Ti were substantially reduced when food ingestion is considered.

[Ion exchange interactions on silica gel layers. III. Salts of organic bases with organic acids. Organic acids and sodium salts]. / Szilikagél rétegen vébemenö ioncserés kölcsönhatások. III. Szerves bázisok szerves savakkal alkotott sói. Szerves savak és nátriumsók.

By thin-layer chromatographic and spectroscopic (UV, IR) methods it has been proved that bass and acid are formed from salts of organic bases with organic acids during primary interaction because of the ion exchange behaviour of the silica gel layer. The organic acids formed have interacted with metals on the layer during secondary ion exchange and they migrate further as salts again. It has also been established that the extent of secondary ion exchange between metal silanate groups and acids depends on pKS values of acids. On the basis of investigations it can be ascertained with great probability that organic acids of pKS greater than 7 do not interact with metal silanate groups of silica gel layer. Sodium salts of organic acids of pKS less than 3 values similarly do not interact on the other hand sodium salts of organic acids of pKS greater than 3 values are able to interact with silanol groups. It has been established by flame atomic emission method that salicylic acid interacts with sodium ion and 86% of it migrates further as sodium salicylate.

Collection of traces of metals on carboxy cellulose cation-exchanger.

Carboxy cellulose ("C-cell") is a cation-exchanger based on cellulose and having carboxyl functional groups with pK 3.46 +/- 0.05 at 20 +/- 1 degrees in 1M sodium chloride. The capacity of the exchanger is pH-dependent and the maximum is 0.22 mequiv/g. The capacity is also influenced by the dielectric constant of the medium and by the swelling of the cellulose. C-cell is suitable for the collection of metal ion impurities from aqueous and non-aqueous media.