Ammonia analysis

Ammonia analysis for oxygen permeation through polyethylene,... 

Boric acid is used as an antiseptic in mouthwashes, eye washes, and ointments a preservative in natural products to protect wood against insect damage in washing citrus fruits as a catalyst in hydrocarbon oxidation as a flame retardant in cellulose insulation in nickel electroplating baths and as a buffer in ammonia analysis of wastewaters hy acid titration. 

Avanzino, R.J. and V.C. Kennedy. 1993. Long-term frozen storage of stream water samples for dissolved orthophosphate, nitrate plus nitrite and ammonia analysis. Water Resour. Res. 29 3357-3362. 

Figure 2. Calibration curve for ammonia analysis by Nesslers reaction (ammonium chloride).

The phenol-hypochlorite (Indophenol-blue) method was used for ammonia analysis (Solorzano, 1969). Appropriate sample sizes were fixed with phenol within 24 hours of collection (Degobbis, 1973) and stored at all times at 4 C. Analyses were made within 2 weeks of collection. The reagent dilutions given by Presley (1971) were used, but the quantity added was doubled. All reaction and color development was done in polyethylene scintillation vials. Color development was allowed for 6-8 hr to obtain a straight-line standardization curve blanks (always <0.010 absorbance with respect to distilled water, 1-cm cell) were insignificant compared to sample absorbances and precision better than 3%. Standards were diluted immediately before use. 

Quantitatively transfer the solution from the previous ammonia analysis in part C to a 250-mL or larger beaker. Add 0.5 M aqueous ammonia, NH3, slowly from your buret until the pH of the solution is 9-10. Add 20. mL of the pH 10. buffer. If the resulting solution is cloudy, slowly with stirring add more buffer until the solution clears or until the total volume of added buffer is 30. mL. Quantitatively transfer the solution to a 500-mL volumetric flask, and dilute the solution with distilled water to the "mark." Mix the solution thoroughly. Rinse and fill your buret with this solution. Measure precisely 50.00 mL of the solution into a clean 250-mL Erlenmeyer flask. Add an additional 125 mL of distilled water to the flask, and heat the solution to 50-60°C (Laboratory Methods D). Add about 0.1 g of Murexide Tablet indicator (0.1 g is approximately the amount if you have 0.5 cm on the end of your spatula) to the flask. Be careful you should not add excess indicator. Clean the buret, and fill it with your standardized EDTA solution from part B. Titrate the warm metal ion solution with EDTA to a blue endpoint which persists for at least 30. seconds. Record the initial and final volumes of EDTA solution in TABLE 17.ID. Repeat the analysis with a second 50.00-mL portion of the solution from sample 1 in part C. Then repeat the copper analysis in duplicate again if a second sample is available from part c. 

Determination of alkali metals, alkaline earth metals, and ammonia is the most often used application of ion chromatography in the range of cation analysis. The key advantage of this method is the ability to determine ammonia in complex samples that contain both inorganic cations and organic amines, as the latter compounds can interfere with the conventional colorimetric or ion selective electrode methods used for ammonia analysis. 

Also shown in Figure 3 is TP hydrolysis of PAM in aqueous solution as measured by the titration method. The data shown were obtained via three separate aging experiments. For comparison with the aqueous hydrolysis curve determined by ammonia analysis, a similarly complex curve has been drawn through the composite data for the three titration experiments. Such a curve appears to give a reasonable fit to the data, but is admittedly arbitrary. Without benefit of the ammonia analyses (curve b), one would probably be inclined to represent the titration data as a smooth curve. A similar comment applies to curve a of Figure 3. 

This study has examined three methods for analyzing the TP hydrolysis of PAM. The ammonia analysis method is the most interesting since it appears to enable resolution of subtle details of the hydrolysis process, which are not readily detectable by the 1C or the titration methods. Comparison of hydrolysis data from the ammonia or 1C methods, vs. the titration... 

Hibbard T, Killard A (2011) Breath ammonia analysis clinical application and measurement. Crit Rev Anal Chem 41 21-35... 

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