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SPECIAL SCIENTIFIC REPORT-FISHERIES Na 349 349 CHEMICAL ANALYSES OF MARINE AND ESTUARINE WATERS USED BY THE GALVESTON BIOLOGICAL LABORATORY SPECIAL SCIENTIFIC REPORT-FISHERIES Na 349 UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE United States Department of the Interior, Fred A. Seaton, Secretary Fish and Wildlife Service, Arnie J. Suomela, Commissioner Bureau of Commercial Fisheries, Donald L, McKernan, Director CHEMICAL ANALYSES OF MARINE AND ESTUARINE WATERS USED BY THE GALVESTON BIOLOGICAL LABORATORY by Kenneth T. Marvin, Zoula P. Zein-Eldin, Billie Z. May and Larence M. Lansford Chemists Galveston, Texas United States Fish and Wildlife Service Special Scientific Report— Fisheries No. 349 Washington, D. C. June 1960 CONTENTS Introduction 1 Sample treatment prior to analysis 1 Sample storage containers 2 Analytical methods 2 Standard samples 2 Phosphate 3 Inorganic only 3 Total and inorganic 3 Total only 4 Nitrate-nitrite 5 Nitrite 5 Salinity 6 Copper 6 Sulfide 7 Oxygen 7 Total carbon dioxide 8 Ammonia 10 Chlorophyll 10 "Carbohydrates" 11 "Protein" (tyrosine equivalent) 12 Washing procedure for all analytical glassware 12 Literature cited 13 111 CHEMICAL AMLYSES OF MAP.INE AND ESTOARIKE mTERS USED BY TBE GALVESTON BIOLOGICAL lABORATORY by Kenneth T. Marvin, Zoula P. Zein-Eldin, Billie Z. May and Larence M. Lansford ABSTRACT This paper describes the chemical techniques and procedures used hy the Biological lahoratory of the U. S. Bureau of Commercial Jlsherles, Galveston^ Texas, for analyzing samples Involved In the chemical and hlo- logical survey of the marine and estuarlne waters of the Gulf of Mexico and also In the many laboratory and field studies and experiments that have heen made pertaining to the red tide investigation. During the past 12 years the staff of All samples collected from the M/Vs the U. S. Bureau of Commercial Fisheries, Kingf ish and Alaska that were subject to Galveston, Texas, has published papers per- bacterial and/or chemical deterioration were taining to the hydrography and chemistry of quick-frozen immediately after collection. the Gulf of Mexico and also problems rela- Ctollier and Marvin (1953) showed that signi- tive to the red tide. Included were data ficant changes in the phosphate ratio of collected from the M/V Pompano from 1949 to some waters occurred within 30 minutes after 1952 (Graham et al. 1954, and Marvin 1955a), collection, but that the ratio could be the MA Alaska from 1951 to 1953 (Collier effectively stabilized by quick-freezing. 1958), and the M/V Kingfish from 1954 to May (unpublished msinuscript) showed that date (Finucane and Dragovich 1959). variations in the carbohydrate-like raatericil in sea water could be minimized by similar The purpose of this paper is to pre- treatment. After quick-freezing, samples sent the chemical methods which were used were stored at below freezing temperatures to obtain the data utilized in these publi- until delivered to the chemistry laboratory cations. We have endeavored to describe for analysis. Our usual freezing bath con- the techniques and procedures in a form sisted of a vat of 38 percent ethylene gly- usable by chemical aids or technicians with col (commercial antifreeze) held at about a minimum of supervision. -20° C. in a quick-freeze cabinet. Freezing can reduce the air pressure within a sample container to a point where impurities around SAMPLE TREATMENT PRIOR TO ANALYSIS the cap-glass junction will be drawn into the container. We minimized this effect by No attempt was made to stabilize the sealing the junction with plastic insulation to Scotch #33). The seal samples collected from the M/V Pomp ano . tape (similar With the exception of salinity and total should not be allowed to come in contact phosphate analyses, all determinations were with the freezing solution. performed on board ship immediately after collection. Salinity, copper, eind total phosphorus samples did not require preservation. The semipermeable membrane under freezing latter, however, were "baited" with a pinch conditions. Samples frozen in this type of of thorium carbonate (Harvey 1948) to pre- container have shown as much as a 2-percent vent the accumulation of phosphorus on the decrease in salinity concentration within sides of the container. An alternative a year. Water from the same samples stored method that we found satisfactory and have at room temperature have shown a salinity used on occasion consisted of adding the increase of over 1 percent during the same amount of H2SO4 called for in the analytical period. procedure immediately after collection. Sulfide, CO2 , and O2 samples were analyzed Sample evaporation can virtually be immediately after collection. We found the eliminated by sealing containers with poly- practice of fixing O2 samples and titrating seal screw caps. Salinity samples, for them later resulted in an error because the example, have remained constant for as long amount of free iodine in the supposedly as a year and a half when sealed in this fixed sample increased with time. manner, and we strongly recommend their use The rate of reactions, which includes the development of color, depends among ANALYTICAL METHODS other things on temperature. For this rea- son the analyst must be sure that all sam- The colorimetric procedures that fol- ples and standards are brought to the same low refer to the Fisher A. C. electrophoto- temperature before adding reagents. Stand- meter, the instrument used for the determi- ard samples were interspersed among the nation of the majority of samples collected regular samples rather than being run as a from the M/V Kingf ish and also the MA Alaska . separate group. We have found that this The colorimetric analyses of samples col- practice reduces operator bias. lected from the M/V Pompano , however, were carried out visually with Nessler tubes. SAMPLE STORAGE CONTAINERS Standard Samples The selection of proper sample con- With a few exceptions, the methods tainers is of considerable importance. We described below require the use of labora- have found, after considerable experimenta- tory-prepared standard samples. Initially tion, that pyrex is equal to or superior to we employed distilled water in the prepara- soft glass, particularly for the storage of tion of these. However, it became evident total and inorganic phosphate and nitrate- that the percent recovery depended, to some nitrite samples. During our survey work extent, on the type of water. For this (M/V Pomp ano ) , those samples that were not reason we endeavored, when possible, to era- analyzed on board ship (salinity and total ploy used portions of the samples for the phosphorus) were stored in citrate bottles. preparation of standards. If a sufficient During the initial collection programs in- volume cannot be obtained for this purpose, volving the M/V Alaska , frozen samples were it is recommended that the percent recovery stored in "Kimble" type screw-cap 25 by 200 be determined by "spiking" a few samples mm. (Culture tubes. Salinity and unfrozen with the standard solution. total phosphate samples were stored in 4- ounce prescription "Duroglas" bottles. It Standard samples were prepared from was during the latter phase of the Alaska compounds of known purity and formula program that pyrex was found to be superior weight that contained the element, nutrient, to the softer glass, particularly for the etc., under consideration. The compounds analyses mentioned. Subsequent collections selected were readily soluble but were not (M/V Kingf ish ) employed pyrex storage con- hygroscopic or deliquescent to the extent tainers for all samples except salinities that they absorbed large amounts of atmos- which were stored in 4-ounce prescription- pheric moisture. The compounds used were type bottles. either bone dry or of a known moisture content. This enabled all weights to be We did not use polyethylene containers reduced to a bone-dry basis. Final amounts because the material acts as an adsorbent, used in standard samples were obtained by reducing the reliability of an analysis. dilution of the relatively concentrated Further, polyethylene becomes an effective stock solution. : Two compounds were usually employed vigorously. Clean each cap-glass junction in the preparation of each series of stand- with a jet of distilled water, remove caps, ard samples. We discouraged the practice and dispense 25-milliliter portion into the of using stock solution more than once. The sample flasks with a large bore 25-milli- practice of starting each series of standard liter graduated pipette. samples from the "dry" compounds rather than from preserved stock solutions, and also of 5. Add 1 drop of stannous chloride using two different compounds to a series reagent to the first sample flask and then of standard samples, enabled the analyst to swirl the flask thoroughly. Thirty seconds detect systematic errors that could reduce later, add a drop to the second flask and the accuracy of his data. swirl. Continue at 30-second intervals until all flasks have been treated. To correct for glassware and reagent contamination, blanks consisting of "pure" 6. Determine the density of the blue water were treated in the same manner as color that will develop if there is any unknown samples. Any color that developed phosphate present with a Fisher a.c. elec- was due to impurities which were corrected trophotometer equipped with a 650 A filter by subtracting the blank sample readings and a 23-milliliter cell. Color-density from those of the regular samples. System- determinations are made 30 minutes after the atic errors can be introduced by using addition of the stannous chloride reagent. a low quality distilled water in preparing If analyst cannot check a sample every 30 blank samples. We have found that a satis- seconds, increase the time interval in item factory grade can be prepared by distilling 5 as necessary. tap water two times in a borosilicate glass still.
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