J.P. Riley

The automatic determination of nitrate in sea water

Abstract A Technicon AutoAnalyzer has been applied to the determination of 0–400 μg NO 3 − -N/1. in sea water. The sample is mixed with an ethylenediamine tetraacetic acid reagent of pH 6·5–7·0 and passed through a coil containing cadmium filings. The resultant nitrite, which is formed in ∼ 75% yield is determined by Bendschneider and Robinsons method. Nitrite itself is reduced to an extent of ∼ 5% during the process, and allowance may be made for its presence. About 30 samples per hour can be processed. The method gave a coefficient of variation of 1·6% at a level of 200 μg NO 3 | stuggerred | − -N/1.

The bromide/chlorinity and sulphate/chlorinity ratio in sea water

Abstract Water samples collected from the worlds oceans for the National Institute of Oceanography for the study of the inter-relationships between chlorinity, electrical conductivity and density have been analysed for bromide and sulphate. Bromide determinations carried out on 219 samples showed that the bromide/chlorinity ratio was 0·003473 ± 0·000012. Sulphate determinations were performed on 345 samples and gave a sulphate/chlorinity ratio of 0·14000 ± 0·00023. No significant deviations from these ratios were found for any locations with the exception of the Baltic; figures for the latter have been omitted when calculating the above ratios.

The solubility of gases in distilled water and sea water—IV. Carbon dioxide

Abstract The solubility of carbon dioxide in distilled water and (acidified) sea water (chlorinity 0–20‰) has been measured over the temperature range 1°–35°C. Measurements were made by stripping carbon dioxide from a known volume of the saturated water and determining it gravimetrically. The results for distilled water are in reasonably close agreement with those of Bohr (1899) and Morrison and Billett (1952).

The concentrations of cadmium, copper, iron, manganese, molybdenum, nickel, vanadium and zinc in part of the tropical north-east Atlantic ocean

Abstract Determinations of cadmium, copper, iron, manganese, molybdenum, nickel, vanadium and zinc have been carried out on water samples from the tropical north-east Atlantic Ocean, using a chelating ion-exchange concentration method followed by atomic absorption spectrophotometry, or for molybdenum and vanadium by colorimetry. The results indicate that cadmium, iron, manganese and nickel are relatively uniformly distributed in this area, whereas molybdenum, vanadium, zinc and to some extent copper show larger variations of a random nature.

The electrical conductivity/chlorinity relationship in natural sea water

Abstract Chlorinity and conductivity ratio at 15°C have been determined for a wide range of natural sea waters. Mathematical expressions have been computed, relating chlorinity and salinity to conductivity ration. In addition, the temperature coefficient of conductivity ratio has been determined, and a formula derived. These measurements form the basis of new International Tables, for use with conductivity salinometers.

The chemical composition of the hot salty water from the bottom of the Red Sea

Abstract Samples of a hot salty water discovered in a deep basin in the Red Sea have been analysed for dissolved gases and major and minor constitutents. It is shown that this water is different in composition from ordinary sea water and some possible explanations of its composition are discussed.

The determination of amino-acids in sea water

A comparison has been made between the published methods of concentrating amino-acids from sea water for analysis. Very poor recoveries were obtained by coprecipitation with ferric hydroxide (Tatsumotoet al. 1961) and by the method of Degenset al. (1964). Recoveries by coprecipitation with the hydroxides of gallium, aluminium and indium were also poor. Recoveries of ∼90% were attained by the procedure of Palmork (1963b); and this has been used in conjunction with thin layer chromatography in a semiquantitative method for the determination of amino-acids. The sea water (2·5 1.) is concentrated to about 15 of its original volume in a climbing-film evaporator. The concentrate is transferred to a rotary-film evaporator and evaporated in vacuo. The salts which crystallize are removed from time to time. The final desalting process is carried out by cation exchange. The amino-acids are separated from one another by thin-layer chromatography and determined photometrically as their ninhydrin compounds. Eleven amino-acids have been determined in water samples from the Irish Sea; their concentrations range from 2 to 16 μg/l.

The lithium content of sea water

Abstract Lithium has been separated from the other ions present in sea water by ion exchange, and determined by flame spectrophotometry—the method shows a variance of 1·1%. Thirty samples of sea water from all the oceans and major seas have been analysed, and it was found that their lithium contents were proportional to the chlorinity. The average lithium content of water of chlorinity 19·374% was 183 μg/l.

The automatic determination of phosphate in sea water

A Technicon AutoAnalyzer has been used for the photometric determination of 0–90 μg PO43− − P/l. in sea water and natural waters. Photometric measurement is made on the blue coloured compound produced by the reaction of phosphate with a single solution reagent containing acid, ammonium molybdate, ascorbic acid, together with a small amount of potassium antimonyl tartrate. A linear relationship is found between optical density and phosphate concentration up to at least 2500 μg PO43− − P/l. The method shows a coefficient of variation of 0·86% at a level of 40 μg PO4 − P/l. Up to 20 samples can be analyzed per hour.

The direct gravimetric determination of the salinity of sea water

Abstract The direct method of salinity determination devised by Guntz and Kocher has been investigated and refined. The modified method has a coefficient of variation of 0·026%. The salinities obtained with it for a series of 15 sea waters have been compared with those determined by electrical conductivity and by titration. It was found that in general the results were within 0·015% S of the results obtained by conductivity and titration.