Square Wave Po1arography of Uranium(VI). II. Influence of Surface Active Agents

The influence of surface active ag ents on the square wave polarographic behaviour of uranyl acetylacetone was investiga t ed. Tritone-X-100 decreases specifically the S.W. peak height of each uranyl-acetylacetonato species, i.e. the adsorption layer is specifically penetrable by each one. From this sp ecific depression the over-all stability constant of uranyl acetylacetonato complexes, in 1 M sodium perchlorate, was calculated as log ~2 = 12 .5. This is in agreement with earlier obtained results3• Elec trocapillary curves for T-X-100 and acetylacetone are also prese nted

Učinak sumpornog dioksida i dima na učestalost sekretornog otitisa

The study deals with the effects of sulphur dioxide and smoke as air pollutants on the incidence of secretory otitis media. Although various atmospheric irritants, such as sulphur dioxide and smoke, have been reported to increase proneness to infection and allergy stabilization, and to cause Eustachian tube obstruction and development of secretory otitis media by way of infection and allergy reaction, such statements appear to be challenged by the results obtained in this study. No correlation was found between the number of children hospitalized for secretory otitis media, and the mean and maximum monthly concentrations of sulphur dioxide and smoke in the air. Although there has been a steady decrease in sulphur dioxide and smoke concentrations over the past decade, the number of cases of secretory otitis media has not only failed to follow that decrease but has actually increased.U ovom radu istraživan je utjecaj sumpornog dioksida i dima, kao onečišćivača atmosfere, na nastanak sekretornog otitisa. Iako različiti iritansi iz atmosfere povećavaju vjerojatnost infekcije i alergijske senzibilizacijc, djelujući na sluznicu respiratornog trakta i uzrokujući zatvaranje Eustachi-jeve cijevi i razvoj sekretornog otitisa, u ovom radu to nismo uspjeli dokazati za sumporni dioksid i dim. Nije dokazana povezanost koncentracije sumpornog dioksida i dima i broja djece hospitalizirane zbog sekretornog otitisa. U proteklom desetljeću vrijednosti sumpornog dioksida i dima u zraku snižavale su se, dok broj sekretornih otitisa ne samo da nije pratio taj pad, nego se povećao

Application of ASV for Trace Metal Speciation II. Digital Simulation of Neopolarogram Using Hanging-mercury-drop Electrode

A program for the digital simulation of neopolarography is described and the results of neopolarograms using hanging mercury drop electrodes are discussed

Raspodjele jodata i jodida u vodama stratificiranog estuarija

Speciation and distribution of inorganic iodine in the highly stratified Krka estuary (east coast of the Adriatic Sea) were investigated in the period from December 2000 to April 2001. Conservative behavior of total inorganic iodine was confirmed during the investigated period, but significant temporal and longitudinal variations were also observed. Concentrations of iodate and iodide were less variable in the more saline layers (S ≥10) than in the upper brackish and interfacial layers, indicating lower dynamics and less pronounced influence of secondary processes on the inorganic iodine distribution. An increase in iodate and iodide concentrations toward the estuary mouth was determined in the upper layers. Seasonal variations in iodate and iodide distributions in the brackish layer were indicative of the important role of the freshwater phytoplankton and organic matter for the inorganic iodine cycle in the estuary.Raspodjele kemijskih vrsta anorganskog joda u visoko stratificiranom estuariju rijeke Krke (istočna obala Jadranskog mora) proučavane su u razdoblju od prosinca 2000. do travnja 2001. godine. Kroz promatrano razdoblje potvrđeno je konzervativno ponašanje ukupnog anorganskog joda, a uočene su i značajne vremenske i longitudinalne razlike u raspodjelama. U slanijim slojevima (S ≥10) koncentracije jodata i jodida su znatno manje varirale u usporedbi s onima u bočatom sloju i međusloju, što ukazuje na slabiju dinamiku i slabije izražen utjecaj sekundarnih procesa na raspodjelu anorganskog joda. U gornjim slojevima utvrđen je porast koncentracija jodata i jodida prema izlazu iz estuarija. Sezonske različitosti u raspodjelama jodata i jodida u bočatom sloju pokazatelj su važne uloge riječnog fitoplanktona i organske tvari za kruženje anorganskog joda u estuariju

Polarographic Determination of Ruthenium in Citrates and Tartrates Solutions

Polarographic methods are proposed for the determination of small amounts of ruthenium in two new supporting electrolytes: a. citric acid (0.3 M) and sodium hydroxide (0.15 M); b. tartaric acid (0.2 M), sodium hydroxide (0.1 M) and thymol (0.009 %). Determination of ruthenium is applicable in the concentration range from 4 to 120 micrograms of ruthenium per milliliter with a relative standard errors from 15 to 0.8 % in both electrolytes. Hydrochloric, sulfuric and perchloirc acids (up to 0.5 N) do not interfer, but in the presence of nitric acid (any traces of nitrites) polarographic determinations are impossible