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Articles by T.H. Flower
Total Records ( 5 ) for T.H. Flower
  Muhammad Ayyaz Khan and T.H. Flower
  Organic nitrogen compounds were evaluated for interferences in NH4-N determination in water, 2M KCl and 0.5M K2SO4 at NH4-N level of 0 and 1.0 mg l-1. The results revealed that organic nitrogen compounds interfere negatively in NH4-N determination using the Technicon AutoAnalyzer II. Soil extracting solutions like 2M KCl and 0.5M K2SO4 further increased interferences by these compounds. These results suggested that a pre-treatment step either distillation or gas phase dialysis should be included to reduce the interferences caused by the organic nitrogen compounds in the NH4-N determination by the Technicon AutoAnalyzer II.
  Muhammad Ayyaz Khan and T.H. Flower
  Inclusion of original dialysis system with Technicon AutoAnalyzer II did not show smooth flow which resulted in non reproducible peaks. Air flow across the dialysis membrane disturbed the air bubble pattern. The chemistry of main Ammonium-N system was affected by 0.1M HCl in the acceptor stream. Therefore, 0.01M hydrochloric acid was found suitable in the accepter stream of the dialysis.
  Muhammad Ayyaz Khan and T.H. Flower
  The development of a gas dialysis system proved that ammonium-N recovery was inversely proportion to acceptor flow rate. The relationship between amonia trapping and acceptor flow rate was considered a crucial parameter and the best flow rate for donor and acceptor streams was chosen for the analysis of water and extract samples. The Technicon silicon gas dialysis membrane showed very low ammonia transference. Polytetrafluoroethene (PTFE) membranes allowed higher amounts of ammonia to be transferred through them. Recovery of ammonia using the standard 6 inch dialyser was 56.7 percent. Analysis at 20 samples per hour showed adequate peak separation and good peak shapes. The standard deviation of the results was between 0.002 and 0.004 for a 1 mg l-1 ammonium-N solution. Calibration curves were linear (y=4.14+15.7x, r2=0.99 and y=5.11+42.82x, r2=0.98). Hence, the developed system was sufficiently precise and reliable for its use in NH4-N determination.
  Muhammad Ayyaz Khan and T.H. Flower
  The dialysis system was included in the main manifold for ammonium-N determination of the Technicon AutoAnalyzer II. Studies using this system indicated that only traces of NH4-N were present as impurities in organic nitrogen compounds such as urea, aspartic acid, lysine and histidine. Positive and negative interferences in the NH4-N determination were attributed to hydrolysis or participation of the organic nitrogen compounds in the colorimetric reaction. These positive and negative interferences were eliminated by gas dialysis. The level of random variability measured with dialysis was consistant with random variability due to solution preparation and to the system complexity. The dialysis system was further developed for the determination of NH4-N in Kjeldhal digests. Dialysis use with Technicon AutoAnalyzer II did not disturb the precision of the system.
  Muhammad Ayyaz Khan and T.H. Flower
  This study was conducted to investigate the possible changes in the composition of effluent in relation to its nutrient stability during storage and its ability to supply plant available nutrients. The samples collected from high rate algal ponds (HRAP) were stored with the aim of storage effect on nutrient stability in the algal pond effluent. The trend of change in the chemical composition of algal pond effluent suggested that it can be stored for a week at 2°C with only minor changes in ammonium, nitrite, nitrate, phosphate and potassium during storage. Fresh or stored samples can be applied to the pot experiments but their analysis prior to each application will be essential.
 
 
 
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