The indophenol method
was used for the determination of urease activity by measuring ammonia production as defined by Weatherburn .
Ammonia was determined by the indophenol method
, and measured using a spectrophotometer (Biospectro; SP220; Curitiba, PR, Brazil; [lambda] = 640nm) according to the American Public Health Association (APHA, 1998).
Preparation of aerosol and air samples for the determination of ammonia by the indophenol method
Ammonium ions were analyzed through Indophenol Method
using UV/Visible spectrophotometer.
Urease inhibition activity was determined by measuring ammonia production using the indophenol method
as described by Weatherburn (Weatherburn 1967).
Total ammonia nitrogen in water samples were determined weekly by the indophenol method
Tomohiro S Determination of Vitamin C (ascorbic acid) by indophenol method
Determination of ammonia in sea water by the indophenol method
and its application to the coastal and off-shore waters.
Determination of ammonia and Kjeldahl nitrogen by indophenol method
Total ammonia was determined in extracted water samples (daily at 11:00h) with the colorimetric indophenol method
Selmer-Olsen AR (1971) Determination of ammonium in soil extracts by an automated indophenol method
The remaining dried soil was kept for analyses of total nitrogen (N) with the indophenol method
and phosphorus (P) with the molybdenum blue method, after digesting 250 mg of soil in a sulfuric acid and selenous acid mixture for 1 h (Kedrowski 1983).