9.2
Metals
9.2.1
Antimony
Metals
213
Abu-Hilal and Riley [619] have described a spectrophotometric procedure for the
determination of antimony in algae. After a preliminary oxidative digestion with
concentrated nitric acid, then concentrated sulphuric acid, the element is quantitatively coprecipitated at pH 5.0 with hydrous zirconium oxide. The precipitate is dissolved in acid, and, after reduction with titanium(III) chloride, antimony is oxidized to
antimony(V) with sodium nitrite. The ion-pair of the SbC1 6 ion with crystal violet is
extracted with benzene, and its absorbance is measured at 610 nm. The detection limit
is 0.005 j.lg I-I. A wide range of anions and cations causes no interference at levels
many times those in algae. The relative standard deviation is 1.8 % for samples of
Pelvetia canaliculata (0.19 j.lg Sb g-l). A 98-101 % recovery of antimony was obtained
in spiking experiments.
Kantin [620] gives details of a procedure developed for the determination of
antimony in marine algae by atomic absorption spectroscopy with hydride generation, and presents results from analysis of three species of marine algae from coastal
waters of California. Pentavalent antimony was the dominant form found, but Sargassum sp. contained up to 30 % of trivalent antimony.
9.2.2
Arsenic
Whyte and Englar [621] have described methods for the analysis of inorganic and
total arsenic in several species of marine algae. Arsenic trichloride formation and
distillation was used to determine inorganic arsenic, and acid-oxidative digestion for
total arsenic.
The arsine generation-spectrophotometric method [247] for the determination of
arsenic, described Sect. 4.2.1 for the determination of arsenic in marine sediments,
has been applied to the determination of arsenic in algae. A recovery of 96-99 % of
added arsenic was obtained in spiking recovery experiments carried out on the
microalgae Echlonia radiata.
9.2.3
Bismuth
The flameless atomic absorption spectrometric method [250], described under bismuth in Sect. 4.2.2 for the determination of bismuth in marine sediments, has been
applied to the determination of down to 3 pg of bismuth in marine algae. Using this
method, 0.005 mg kg-I bismuth was found in kelp and 0.009 mg kg-I bismuth in
macrocrystis taken in San Onofre, California.
Metals
9.2.1
Antimony
Metals
213
Abu-Hilal and Riley [619] have described a spectrophotometric procedure for the
determination of antimony in algae. After a preliminary oxidative digestion with
concentrated nitric acid, then concentrated sulphuric acid, the element is quantitatively coprecipitated at pH 5.0 with hydrous zirconium oxide. The precipitate is dissolved in acid, and, after reduction with titanium(III) chloride, antimony is oxidized to
antimony(V) with sodium nitrite. The ion-pair of the SbC1 6 ion with crystal violet is
extracted with benzene, and its absorbance is measured at 610 nm. The detection limit
is 0.005 j.lg I-I. A wide range of anions and cations causes no interference at levels
many times those in algae. The relative standard deviation is 1.8 % for samples of
Pelvetia canaliculata (0.19 j.lg Sb g-l). A 98-101 % recovery of antimony was obtained
in spiking experiments.
Kantin [620] gives details of a procedure developed for the determination of
antimony in marine algae by atomic absorption spectroscopy with hydride generation, and presents results from analysis of three species of marine algae from coastal
waters of California. Pentavalent antimony was the dominant form found, but Sargassum sp. contained up to 30 % of trivalent antimony.
9.2.2
Arsenic
Whyte and Englar [621] have described methods for the analysis of inorganic and
total arsenic in several species of marine algae. Arsenic trichloride formation and
distillation was used to determine inorganic arsenic, and acid-oxidative digestion for
total arsenic.
The arsine generation-spectrophotometric method [247] for the determination of
arsenic, described Sect. 4.2.1 for the determination of arsenic in marine sediments,
has been applied to the determination of arsenic in algae. A recovery of 96-99 % of
added arsenic was obtained in spiking recovery experiments carried out on the
microalgae Echlonia radiata.
9.2.3
Bismuth
The flameless atomic absorption spectrometric method [250], described under bismuth in Sect. 4.2.2 for the determination of bismuth in marine sediments, has been
applied to the determination of down to 3 pg of bismuth in marine algae. Using this
method, 0.005 mg kg-I bismuth was found in kelp and 0.009 mg kg-I bismuth in
macrocrystis taken in San Onofre, California.