On-line determination of residual aluminium in potable and treated waters by flow-injection analysis

A portable, automated, flow-injection-based solid-state spectrophotometric field monitor for the determination of residual dissolved aluminium in potable and treated waters is described. Aluminium is determined by complexation with pyrocatechol violet to form a colloidal lake with a maximum absorbance at 580 nm. Interference from iron(III) is masked by reduction to iron(II) and complexation with 1,10-phenanthroline. The monitor operates on a 30-min analytical cycle, i.e., with 48 results per day, and each cycle includes an autocalibration step. Over the course of a 3-month field trial the reliability was greater than 90%. The performance conforms to industry specifications for both overall accuracy (bias < ± 10%) and repeatability (relative standard deviation < ± 10%), the linear range is 0–1000 μg l^?1 and the practical limit of detection is 45 μg l^?1.     

Extraction-photometric determination of thorium with chlorophosphonazo-III

A simple and rapid spectrophotometric determination of thorium is described. The thorium-chlorophosphonazo-III complex is extracted into 3-methyl-1-butanol from 2.0–3.0 M hydrochloric acid solution. Maximum absorbance occurs at 620 and 670 nm and Beer's law is obeyed at the latter wavelength over the range of 0–15 μg per 10 ml of the organic phase. The molar absorptivity is 12.2·10⁴ l mole^-1 cm^-1 at 670 nm. Thorium can be determined in the presence of fluoride, oxalate, sulfate and EDTA. Many common cations do not interfere, but uranium, zirconium and niobium interfere seriously.     

Flow-injection photometric determination of trace copper in natural waters

A procedure for the flow-injection photometric determination of trace copper(II) in fresh natural waters is developed using a sorption preconcentration on the Diasorb-IDK-130 adsorbent with iminodiacetate groups. The procedure provides the determination of copper in the concentration range from 0.5 to 20 μg/L     

Investigation of trace and ultra-trace elements of nutritional and toxicological significance in Italian potable waters by INAA

The element concentrations in potable water samples collected in two different urban areas for the water supply, Rome and Florence, are determined by INAA and compared. The results on drinking water of Rome show that the potentially toxic elements (Sb, Hg, Cr, Ni, etc.) are present at levels below the limit values whereas the essential human elements give a convenient nutritional support. Further, it is also evidenced that the elemental composition is quite similar to that of uncontaminated natural waters. According to the drinking water of Florence the characterization of the concentration of elements show an almost good situation except for Al.     

On-line preconcentration and GFAAS determination of trace metals in waters

An on-line separation preconcentration system coupled to electrothermal (graphite furnace) atomic absorption spectrometry was developed. A miniature column packed with iminodiacetic acid ethyl cellulose (IDAEC) was inserted into the loop. A peristaltic pump was used to deliver solutions. A flow of air was driven into the packed column, evacuating it between sample loading, washing and elution. The retained analyte was introduced on-line to graphite furnace using countercurrent elution with HNO₃. The system was applied for the determination of V, Co and Pb in medicinal mineral water samples, and nickel in sea water samples. The detection limits (3σ) were 0.058, 0.022, 0.067, 0.062 μg/l for Co, Pb, V, and Ni, respectively. The R.S.D. (n=5) was <5% at 0.4–1.0 μg/l concentration range.     

Uses of ion-exchangers in the determination of trace elements in waters

Summary The use of ion-exchangers has not only increased in importance in water technology but also in the analysis of waters of different origin. By means of cation- or anion-exchangers, cations or anions may be concentrated and separated, or interfering ions removed. This methodology is applicable not only to inorganic substances but also to organic compounds, particularly acids and bases. Examples are given of the applicability of the procedures.

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Spezielle Anwendungen von Ionenaustauschern in der Spurenanalytik von Wässern

Zusammenfassung Die Anwendung von Ionenaustauschern hat nicht nur in der Wassertechnologie, sondern auch bei der Analytik von Wässern verschiedener Provenienz an Bedeutung gewonnen. Mittels Kationen- oder Anionenaustauschern können Metalle oder verschiedene Anionen angereichert und voneinander getrennt oder auch Störionen entfernt werden. Die Methodik ist aber nicht nur für anorganische Substanzen, sondern auch für organische Verbindungen, insbesondere Säuren und Basen anwendbar. Die Brauchbarkeit der Verfahren wird an Beispielen erläutert.

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Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980.     

Extraction—photometric determination of trace amounts of nitrite in waters

Traces of nitrite in river water can be determined by extraction spectrophotometry. Nitrite in 100 ml of sample water at pH 1.5–3.0 diazotizes p-aminoacetophenone, which is then coupled with m-phenylenediamine at the same pH. The 2,4-diamino-4'-acetyl-azobenzene formed is extracted into 5 or 10 ml of toluene at pH 9 and the absorbance is measured at 450 nm. The molar absorptivity is about 2.3·lO⁴ l mol^?1 cm^?1. The ions normally present in river water do not interfere. The nitrite contents in river waters in Okayama Prefecture, Japan, are 1–30 P.P.b.     

Extraction-photometric determination of trifluoromethanesulfonic acid with Methyl Violet

Optimal conditions were found for the formation of ion associates of trifluoromethanesulfonic acid with Methyl Violet. A procedure was developed for the extraction-photometric determination of trifluoromethanesulfonic acid in the air of the working area and atmospheric air.     

Extraction-photometric determination of indium in zinc-base alloys with bromopyrogallol red

The extraction-photometric determination of indium at the 5 p.p.m. level in highpurity zinc and zinc-base alloys is described. After a preliminary separation of indium by isopropyl ether extraction from hydrobromic acid medium, indium is determined by extraction into benzyl alcohol of its complex with bromopyrogallol red at pH 9.0. It is shown that 2:1, 1:1 and 1:2 complexes can be formed in aqueous and water-ethanol media; the 1:3 complex reported earlier was not found. The composition of the complexes extracted into benzyl alcohol from aqueous solutions at pH 6.5 and 9.0, was found to be 1:2.     

Preconcentration and selective determination of traces of tin in natural waters

A combined preconcentration-photometric determination technique has been worked out for trace concentration of tin in fresh and sea waters. After refluxing the sample acidified to 1M HCl for 2 h, tin is preconcentrated by anion-exchange in the presence of thiocyanate and recovered by elution with dilute HNO₃. Tin is then generated as stannane, caught in permanganate solution, and determined spectrpphotometrically with phenylfluorone. The results are quoted on the determination of tin in several fresh and sea waters in the order of submicrogram of tin per litre. The results for tin are in good agreement with those obtained for these samples by manganese dioxide coprecipitation-hydride generation-phenylfluorone spectrophotometric method that is also newly developed.     

Spatial distribution investigation of radioactivity of potable waters in Luxembourg

A survey of naturally occurring radio-nuclides was performed on the territory of Luxembourg in order to identify the main physical and chemical parameters in drinking waters. During last summer water samples from 316 different outflows were collected twice and analyzed. A routine laboratory sequentional extraction radiochemistry procedure was applied for monitoring low concentrations of radio-nuclides in natural waters. New investigations were done to optimize some analysis conditions for the different determination procedures. A quality assurance procedure was applied. The obtained results are analyzed in term of spatial distribution, supported geology and chemistry.     

Extraction-photometric determination of uranium(IV) with chlorophosphonazo-III

A sensitive spectrophotometric method has been developed for the determination of uranium. The uranium(IV)-chlorophosphonazo-III complex is extracted into 3-methyl-1-butanol from 1.5–3.0 M hydrochloric acid solution. Maximal absorbance occurs at 673 nm and Beer's law is obeyed over the range of 0–15 μg per 10 ml of the organic phase. The molar absorptivity is 12.1·10⁴ 1 mole^?1 cm^?1. Uranium can be determined in the presence of fluoride. sulfate and phosphate. Nitrate ion and elements (chromium, copper, iron) which affect the reduction of uranium(VI) or stability of uranium(IV) interfere.     

Particle discrimination effects in the determination of trace metals in natural fresh waters

Instrumental neutron activation analysis (i.n.a.), atomic absorption spectrometry (a.a.s.), and inductively-coupled plasma atomic emission spectrometry (i.c.p.a.e.s.) have been applied to the determination of Na, K, Mg, Ca, Al, Mn, Fe and Zn in fresh waters containing naturally occurring particles. Scattered results were obtained for the total concentrations of trace metals which were associated to some extent with particles retainable by 0.45-μm filter membranes. Particle discrimination effects are indicated and the fraction of elements included in the final result depends on the method used. For the simultaneous determination of the total concentrations of Al, Mn, Fe and Zn, i.n.a.a. is preferred, as all element fractions present are included in the result. When a.a.s. or i.c.p.a.e.s. is applied, lower results are obtained when particulate matter is present, the results referring only to the acid-soluble low-molecular-weight fraction (< 0.45 μm diameter). When particles are removed prior to the quantifying step, the results obtained on the filtrates by all methods are in good agreement. However, considering the low concentrations of several elements in the separated fractions, i.n.a.a. is most favourable for the determination of aluminium while graphite-furnace a.a.s. is most suitable for zinc. Both methods are applicable for manganese. For Ca, Fe, K, Mg and Na, i.c.p.a.e.s. is recommended.     

Microcoulometric determination of total inorganic and organic sulfur in trace amounts in waters

Sulfur and its compounds are converted to sulfur dioxide which is titrated microcoulometrically. Complete volatilization of inorganic sulfur is effected by adding a little phosphoric acid to the samples; metals are thus converted to their stable phosphate salts. The limit of detection is about 0.1 ppm based on a 25-μl sample. An analysis requires 4–5 min. The only interference arises from > 100 ppm halogen contents.