136
Fish
7.2.2
Total Phosphorus
Total phosphorus in fish has been determined [399] by ashing the sample at 550600°C in the presence of magnesium acetate as an ashing aid, the ash being dissolved
in dilute sulphuric acid and the phosphorus determined spectrophotometrically as
molybdovanadophosphoric acid.
Kirkpatrick and Bishop [400] determined total phosphorus due to organophosphonates in fish. The sample was digested with 1.5 ml of a 98: 230 : 1200: 120 v Iv
mixture of sulphuric acid: water: nitric acid: perchloric acid for 1.5 h at 225°C.
Orthophosphate was then determined in the digest molybdophosphate by ultramicro
spectrophotometry at 830 nm. Recoveries from fish of 2-aminoethyl phosphoric acid,
N-methyl-2-aminoethyl phosphoric acid, N,N dimethyl-2-aminoethyl-phosphoric
acid, 2-amino-3-phosphoropropionic acid, and phosphoserine were in the range 95101 % and relative standard deviations were in the range 1.4-2.4 %.
Elementary phosphorus has been determined in benzene or isooctane extract of
fish by gas chromatography with a flame photometric detector [401].
7.3
Organics
7.3.7
Hydrocarbons
Farrington et al. [402] used column chromatography and thin-layer chromatography
to isolate hydrocarbons, arising from marine contamination, in fish lipids. The hydrocarbon extracts were then examined to select those that could be determined by
gas chromatography mass spectrometry, by combinations of spectrophotometric
methods, or by wet chemistry. As a screening method, gas chromatography was
shown to be fairly accurate and precise for hydrocarbons boiling in the range 287450°C and of suitable polarity.
Farrington et al. [403] also described a gas chromatographic method for the determination of hydrocarbons such as petroleum cuts, fuel oil, and lubricating oils in tuna
meat and cod liver lipid extracts. The cod liver oil samples used in this study were
spiked with known amounts of various commercial hydrocarbon products and subjected to analysis in order to check analytical recoveries. In one recovery procedure,
the cod liver oil sample was refluxed with methanolic 1 N potassium hydroxide to
saponify esters. An ether extract of the digest was prepared, the ether was removed,
and the residue dissolved in chloroform. This extract was subjected to thin-layer
chromatography and gas chromatography. Further cod liver oil samples were chromatographed on a column consisting of layers of alumina and silica gel, elution of
hydrocarbons being carried out with a 5 % solution of benzene in pentane. Solvent
was then removed from the eluate in vacuo and the residue dissolved in a small
volume of carbon disulphide. This extract was then gas chromatographed to give the
distribution of hydrocarbons present.
Fish
7.2.2
Total Phosphorus
Total phosphorus in fish has been determined [399] by ashing the sample at 550600°C in the presence of magnesium acetate as an ashing aid, the ash being dissolved
in dilute sulphuric acid and the phosphorus determined spectrophotometrically as
molybdovanadophosphoric acid.
Kirkpatrick and Bishop [400] determined total phosphorus due to organophosphonates in fish. The sample was digested with 1.5 ml of a 98: 230 : 1200: 120 v Iv
mixture of sulphuric acid: water: nitric acid: perchloric acid for 1.5 h at 225°C.
Orthophosphate was then determined in the digest molybdophosphate by ultramicro
spectrophotometry at 830 nm. Recoveries from fish of 2-aminoethyl phosphoric acid,
N-methyl-2-aminoethyl phosphoric acid, N,N dimethyl-2-aminoethyl-phosphoric
acid, 2-amino-3-phosphoropropionic acid, and phosphoserine were in the range 95101 % and relative standard deviations were in the range 1.4-2.4 %.
Elementary phosphorus has been determined in benzene or isooctane extract of
fish by gas chromatography with a flame photometric detector [401].
7.3
Organics
7.3.7
Hydrocarbons
Farrington et al. [402] used column chromatography and thin-layer chromatography
to isolate hydrocarbons, arising from marine contamination, in fish lipids. The hydrocarbon extracts were then examined to select those that could be determined by
gas chromatography mass spectrometry, by combinations of spectrophotometric
methods, or by wet chemistry. As a screening method, gas chromatography was
shown to be fairly accurate and precise for hydrocarbons boiling in the range 287450°C and of suitable polarity.
Farrington et al. [403] also described a gas chromatographic method for the determination of hydrocarbons such as petroleum cuts, fuel oil, and lubricating oils in tuna
meat and cod liver lipid extracts. The cod liver oil samples used in this study were
spiked with known amounts of various commercial hydrocarbon products and subjected to analysis in order to check analytical recoveries. In one recovery procedure,
the cod liver oil sample was refluxed with methanolic 1 N potassium hydroxide to
saponify esters. An ether extract of the digest was prepared, the ether was removed,
and the residue dissolved in chloroform. This extract was subjected to thin-layer
chromatography and gas chromatography. Further cod liver oil samples were chromatographed on a column consisting of layers of alumina and silica gel, elution of
hydrocarbons being carried out with a 5 % solution of benzene in pentane. Solvent
was then removed from the eluate in vacuo and the residue dissolved in a small
volume of carbon disulphide. This extract was then gas chromatographed to give the
distribution of hydrocarbons present.