M. Harriott

Investigation of the determination of tin tetraalkyls and alkyltin chlorides by atomic-absorption spectrometry after separation by gas-liquid or high-performance liquid-liquid chromatography

A variety of sample presentation and atomisation methods have been examined to obtain sufficient sensitivity for the trace determination of tin tetraalkyls and alkyltin chlorides (RnSnCl4–n; R = methyl or ethyl; n= 1–4) after their separation by gas-liquid or by high-performance liquid-liquid chromatography. Detection limits range from 10–20 µg (flame atomisation) to 1 µg (direct pyrolysis) and 2–20 pg (hydride reduction followed by direct pyrolysis). The construction of systems including an automated hydride generator is described.

Flow-injection extraction-spectrophotometric determination of perchlorate with brilliant green

Abstract Perchlorate (0-2.5 μg ml −1 ) is determined spectrophotometrically at 640 nm after extraction into benzene of its ion-associate with Brilliant Green in a flow-injection manifold with a membrane separator. The injection rate is 20 h −1 . The detection limit is 36 ng ml −1 , based on 250-μl injections. The system is applied to the determination of perchlorate in potassium chlorate after prior selective destruction of chlorate.

Spectrophotometric determination of chromium(VI) by extraction of benzyltributylammonium dichromate

Abstract Chromium(VI) (–100 μg) can be determined spectrophotometrically at 365 nm after its extraction as benzyltributylammonium dichromate into chloroform. The effects of acidity, diverse ions and masking studies are reported.

Flow-injection extraction-spectrophotometric determination of manganese(VII) with benzyltributylammonium cations

Abstract A flow-injection manifold has been developed for the spectrophotometric determination of manganese(VII) at 548 nm after extraction into chloroform of the ion-associate, benzyltributylammonium permanganate. The carrier stream was a pH 6 buffer containing 10% (w/v) ammonium fluoride and the reagent stream was 0.10% (w/v) benzyltributylammonium chloride. The injection rate was 20 h −1 . The calibration graph is linear up to 25 μg ml −1 and the detection limit (3 × baseline noise) is 0.91 μg ml −1 Mn(VII), based on 250-μl injection volumes. The system has been aplied to the determination of manganese in steels and a cupro-nickel alloy.

Flow-injection extraction spectrophotometric determination of bismuth as tetraiodobismuthate(III) with the tetramethylenebis(triphenylphosphonium) cation

Bismuth can be determined spectrophotometrically at 495 nm after its extraction as tetramethylenebis(triphenylphosphonium) tetraiodobismuthate(III) into dichloromethane. The carrier stream is 2 M sulphuric acid and the reagent stream contains 2% (w/v) potassium iodine and 0.4% (w/v) tetramethylenebis(triphenylphosphonium) bromide. The injection rate is 20 h-1. The calibration graph is linear up to 20 μ ml-1 bismuth and the detection limit is 0.24 μ ml-1 bismuth, based on injection volumes of 250μl. The system has been applied to determination of bismuth in pharmaceutical samples.

The extraction, determination and speciation of tributyltin in seawater

SummaryMethods have been developed for the determination, by carbon-furnace atomisation atomic absorption spectrophotometry, of inorganic and of total butyltin in seawater. Concentration/separations are based on the solvent extraction of organotin species directly into toluene and of inorganic tin as its tin(IV) 8-hydroxyquinoline chelate into chloroform. Detection limits are 0.7–0.8 ng.

Flow-injection spectrophotometric determination of cobalt by extraction as tetrathiocyanatocobaltate(II) with the ethylenebis(triphenylphosphoniu) cation

Abstract Cobalt (0–10 μg) may be determined spectrophotometrically at 625 nm after flow-injection extraction into chloroform of the ion associate ethylenebis(triphenylphosphonium) tetrathiocyanatocobaltate(II). The carrier stream contained 10% (w/v) ammonium fluoride and the reagent stream contained 0.5% (w/v) ethylenebis (triphenylphosphonium) bromide and 5% (w/v) ammonium thiocyanate. The injection rate was 20 h −1 . The calibration graph is linear up to 20 μg ml −1 and detection limit is 0.23 μg ml −1 cobalt, based on injection volumes of 500 μl. The system has been applied to the determination of cobalt in a range of tool steels.

Flow-injection extraction-spectrophotometric determination of permanganate with the ethylene-bis(triphenylphosphonium) cation

Abstract Permanganate is determined spectrophotometrically at 545 nm after extraction into chloroform of the ion-associate, ethylene -bis (triphenylphosphonium) permanganate. The carrier stream is pH 6 buffer containing 10% (w/v) ammonium fluoride and the reagent stream is 0.25% (w/v) ethylene-bis (triphenylphosphonium) bromide. The injection rate is 24 h−1. Th calibration graph is linear up to 25 μg ml−1 and the detection limit is 0.58 μg m−1 Mn (VII), based on 250- μl injections. The system is applied to the determination of manganese in a range of steels.

Flow-injection extraction spectrophotometric determination of dichromate with the tetramethylenebis(triphenylphosphonium)cation

Abstract Chromium(VI) (0–5 μg) can be determined spectrophotometrically at 365 nm after flow-injection extraction into chloroform of the ion-associate, tetramethylenebis(triphenylphosphonium) dichromate. The carrier stream is distilled water and the reagent stream contains 1 M sulphuric acid and 0.5% (w/v) tetramethylenebis(triphenylphosphonium) bromide. The sampling rate is 24 h −1 . The calibration graph is linear up to 20 μg ml −1 and the detection limit is 0.44 μg ml−1 chromium, based on injection volumes of 250 μl. The system has been applied to the determination of chromium in a range of steels.

Applications of a slotted tube atom trap and flame atomic absorption spectrometry : determination of bismuth in copper-based alloys with and without hydride generation

Abstract Improved systems are reported for the determination of bismuth (0-0.1%, w/w) in copper-based alloys by flame atomic absorption spectrometry. The use of a slotted quartz tube atom trap (STAT) with nebulised solutions or coupled with hydride generation decreases the characteristic concentrations (nebulized solution, 0.44/0.25, without/with STAT; hydride, 0.022/0.014, without/with STAT) and improved precisions by factors of two compared with those obtained without the use of the STAT. Determination of bismuth in a series of reference materials demonstrates the usefulness of STAT systems for the analysis of metallurgical samples.