Nitrates values

Typical specifications for several common types or grades of acid are shown in Table 13. Similar limits are generally used for other sulfuric acid concentrations, with the exception of turbidity values for high strength acids (and oleum) and SO2 and nitrate values in oleums. Because kon sulfate is relatively insoluble in concentrated acids, the turbidities of 98—99% H2SO4 and oleum may be higher than shown, even at acceptable total kon concentrations. 

Nitrite/nitrate values of 9 GFD + oats and 8 GFD remained high after 1 year... 

The nitrite value can be determined by eliminating the reductor column and standardizing with an appropriate nitrite value. In order to determine the nitrate values, the nitrite alone must be subtracted from the total (nitrate and nitrite). 

The specific gravity of anhydrous lithium nitrate is 2-334 (17 5°), according to P. Kremers 20 and 2 442 (110 ), according to L. Troost. For sodium nitrate, values ranging from 2"09 to 2 29 have been published the older values are too low—... 

The dimensions of a nitrocellulose crystal cell depend on the degree of nitration. Values from the papers of Mathieu [14, 34] characterizing native cellulose and various nitrocelluloses are quoted in Table 38. 

The hydroxy a-amino acids l-serine and l-threonine, used as models for the 2-amino-2-deoxy glyconic acids, have been complexed with Ni(II) at 37 °C in aqueous solutions of 0.15M potassium nitrate. Values for the stability constants were obtained from iso-pH titration data which were collected by alternate, small, incremental additions of metal ion and potassium hydroxide being made such that the pH of the solution remained nearly constant. The data were consistent with the predominance of MLn species, along with additional protonated and hydrolyzed complexes. There was no evidence for the involvement of the hydroxyl group in chelation. By the same iterative computations the complexes formed between borate and mannitol have been analyzed, and the stability constants have been calculated. Complexes with mannitohborate stoichiometries of I.T, 1 2, 1 3, and 2 1 were proposed. 

The first probable values for the molecular size of the native pectins from apple and sugar beet were obtained by Schneider and co-workers.71 These workers prepared the nitro- and acetyl-derivatives in order to avoid the anomalous behavior due to charge effects which occurred using the unsubstituted polysaccharides. From osmotic and viscometric measurements on the nitrate, values for the molecular weight of 30,000-100,000 were found, the constant Km in Staudinger s equation being 6(10)-4. Viscometric measurements indicated that there was little difference in size between the two derivatives. 

As is known, fixed nitrogen is present in seas and lakes in several forms. Nitrates produce the greatest influence on biotic productivity. They, similar to phosphates, are present in the Aral Sea in very low concentrations. Thus, the nitrate nitrogen content in the open part of the Large Sea never exceeded 5 mg m and only in the mouth areas of rivers was it somewhat higher. The nitrate values in the Small Sea were higher. Their content in the surface waters varied from 7.0 to 15.0 mg m and in the bottom layer - from 1.0 to 3.0 mg m . ... 

Homogeneous Nitration. Values of k2 were determined by means of a Nortech SF-3A stopped-flow spectrometer. Equal volumes of dilute solutions of chlorobenzene and nitric acid in 79. 5 siilphuric acid were mixed in a thermostat controlled to 0.001 C, and the change in the transmittance at 350 nm with time recorded on a storage oscilloscope. The concentrations of... 

Figure 2 shows the concentration of soil nitrate values observed in the trial period. For all the treatments, the tendency is characterised by high values in the summer due to the combined effect of fertilisation and native soil N mineralisation, since, in this season, soil conditions are not limiting for biochemical activities (optimal soil water contents maintained by micro irrigation and high soil temperature). On the other hand, low values measured in the winter could be ascribed to the rainfall that may leach nitrates from the superficial soil layer. 

Serum NO (nitrite + nitrate) values were decreased in male C57BL/6J mice (at the start of the experiment 15 months of age) that received 10 pg melatonin/ml drinking water (only during the night hours from 18.00 and 9.00) supplementation for 3 months (Chen et al. 1999). 

The yield of the reduction of nitrate to nitrite depends upon the metal used in the reductor, on the pH of the solution and on the activity of the metal surface. Reaction solutions that are too alkaline or inactive metal surfaces result in only partial reduction solutions that are too acidic, the use of highly electronegative metals or too active surfaces result in the nitrate being reduced further than the nitrite step. In both cases the analysis will result in nitrate values that are too low. The standard electromotive forces Eo of the two reactions... 

The determination of nitrate in seawater is not subject to interferences. It has been claimed that nitrate might occur together with small amounts of hydrogen sulphide. For thermodynamic reasons this can only be true for waters from the transition layers between oxic and anoxic environments where intense vertical turbulent mixing processes occur. In this case the hydrogen sulphide is precipitated on top of the reductor as copper or cadmium sulphide and does not interfere in the nitrate analysis. Nitrate values observed together with hydrogen sulphide should be interpreted with care. 

The apparent nitrate values must be further corrected for the nitrite measured in the same sample. Again assuming a 100 % efficiency of the redactor, the nitrite concentration is subtracted from the nitrate value. If the redactor efficiency is significantly less than 100 %, the nitrite correction may be performed as follows. 

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