Yoshimi Umezaki

Simultaneous determination of heavy metals in waters by inductively-coupled plasma atomic emission spectrometry after extraction into diisobutyl ketone

Abstract Nebulization of more than thirty aliphatic and aromatic liquids into a low power (

The electrothermal atomic absorption spectrometric determination of lead, manganese, vanadium and molybdenum in sea water with ascorbic acid to reduce matrix effects

Abstract The effect of ascorbic acid on the response of several metals in sea water obtained by graphite-furnace atomic absorption spectrometry was evaluated from the variation of peak time and the sensitivity. Matrix interferences from sea water in the determination of lead, manganese, vanadium and molybdenum were suppressed by addition of 10% (w/v) ascorbic acid solution to the sample in the furnace. Matrix effects on the determination of cobalt and copper could not be removed in this way. A direct method for the determination of lead, manganese, vanadium and molybdenum in sea water is proposed.

Comparison of ascorbic acid and related compounds as interference suppressors in electrothermal atomic absorption spectrometry

Abstract Suppression of interferences from sodium, calcium and iron(III) chlorides by addition of ascorbic acid and related compounds was investigated for the determination of Pb, Sn, Mn, V and Mo. Absorption—time curves for these metals with and without ascorbic acid and other compounds showed that the peak appeared earlier for Pb, and later for Sn, Mn, Mo and V when ascorbic acid was present. Suppression of interferences was also achieved, but usually less effectively, by lactones, carboxylic acids, ammonium carbonate and formaldehyde. Carbon monoxide or dioxide generated by pyrolysis of the suppressors may participate in the suppression of interferences.

Determination of trace levels of heavy metals in waters by extraction with ammonium tetramethylenedithiocarbamate and hexamethyleneammonium hexamethylenedithiocarbamate into xylene followed by inductively-coupled plasma emission spectrometry

The determination of Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, V and Zn in river and sea water by inductively-coupled plasma emission spectrometry after extraction with a mixture of ammonium tetramethylenedithiocarbamate (APDC) and hexamethyleneammonium hexamethylenedithiocarbamate into xylene is described. All these elements are simultaneously concentrated 100-fold in a single extract and directly introduced into the plasma. The pH dependences of the extraction and the stabilities of the complexes are reported. The limits of detection of the method range from 0.017 ng ml−1 (cadmium) to 0.5 ng ml−1 (lead). With 100-fold concentration factors, calibration graphs are linear up to 30 ng ml−1 or more.

Determination of ng ml-1 levels of phosphorus in waters by diisobutyl ketone extraction and inductively coupled plasma atomic emission spectrometry

Reduced molybdoantimonylphosphoric acid is extracted into diisobutyl ketone (DIBK) and phosphorus in the extract determined by i.c.p. emission spectrometry at the P I 214.91-nm line. The Mo II 213.61 nm line interfered with the P I 213.62-nm line. The method is applied to 0.2–200 μg of phosphorus in 500 ml of river or sea water. Arsenic(III), Si, Ge, Fe(III) and most anions do not interfere, but As(V) >10 × P) causes positive errors. The detection limit is 0.37 ng P ml-1, and the relative standard deviation for 5 μg of phosphorus is 2.1%.

Determination of submicrogram amounts of arsenic and antimony by d.c. plasma arc emission spectrometry

Abstract The application of a d.c. plasma arc to the determination of submicrogram amounts of arsenic and antimony is described. Arsenic or antimony hydride generated by reduction with granulated zinc or zinc powder is collected in a liquid nitrogen trap and then swept into the plasma. The effects of the argon gas flow rates, d.c. are current, acid concentration, etc. were investigated. The limits of detection are 8 ng for arsenic and 40 ng for antimony. The standard deviations are 3.5% for 0.5 μg As and 4.5% for 0.6 μg Sb Interference from nitric acid up to 0.3—0.5 M could be removed by adding chromium(II) The proposed method was applied to the analysis of waste water and sea water.

Indirect determination of sub-ng ml-1 levels of phosphorus in waters by di-isobutyl ketone extraction of reduced molybdoantimonylphosphoric acid an

Abstract Reduced molybdoantimonylphosphoric acid is extracted into di-isobutyl ketone (DIBK) and phosphorus in the extract is indirectly determined by inductively-coupled plasma emission spectrometric measurement of the Mo II 202.03-nm or Sb I 206.83-nm line. Washing of the extract with acid is unnecessary because of the low solubility of DIBK in water. Arsenic(III), Si, Ge, Fe(III) and most anions do not cause serious interference but arsenic(V) must be absent. The detection limits are 5.2 and 45 pg P ml-1, and the relative standard deviations for 1 μg of phosphorus are 2.0% and 2.5%, for molybdenum and antimony measurements, respectively. The method is applied in the analysis of river and seawater.

Evaluation of interference suppressors in electrothermal atomic absorption spectrometry

Abstract Suppression of interferences from iron(III) chloride and sodium chloride by the addition of ascorbic acid, formic acid and carbon dioxide is investigated for the determination of Pb, Sn, Mn, V, Mo, Co, Cu, Ni and Al. The addition of ascorbic acid was most effective for Pb, Sn, Mn, V and Mo.

Determination of arsenic in sediments by chloride formation and d.c. plasma arc emission spectrometry

Abstract The sediment sample is heated in an induction furnace in hydrogen chloride—argon; arsenic trichloride evolved is trapped and then swept into a d.c. plasma arc. Calcium sulfate addition enhances the signals and suppresses interference from organic matter. The limit of detection is 15 ng As; the relative standard deviation is 3.4% ( n = 10) for 1.5μg As 2 0 3 .