The estimation of ammonia using the indophenol blue reaction

ArticleinClinica Chimica Acta 14(2):185-94 · September 1966with66 Reads
DOI: 10.1016/0009-8981(66)90085-4 · Source: PubMed
The addition of sodium hypochlorite solution of pH 12.5 to an ammonia solution before the addition of sodium phenate has been shown to increase the sensitivity and accuracy of the indophenol blue reaction. This reaction is not temperature-dependent over the range −5° to +25°. The pH of the phenate solution is much less critical when it is added after the hypochlorite; a reagent with a pH in the range 10.6–11.2 is quite suitable.This modified method may be applied to the later stages of Fenton's1 method of estimating plasma ammonia and while it increases the sensitivity and accuracy it does not impair the specificity.
    • "The concentrations of K + , Na + , Ca 2+ , Mg 2+ , Al 3+ , Cu 2+ , Mn 2+ , Pb 2+ , and Zn 2+ in the leachates were measured using the inductively coupled plasma atomic emission spectroscopy (Optima2000). NO 3 À –N was determined by the phenol disulfonic acid spectrophotometric method [Nicholas and Nason, 1957] and NH 4 + –N by the indophenol blue spectrophotometric method [Horn and Squire, 1966]. The P concentration was measured by the stannous chloride method (American Public Health Association Standard Methods, a Data except for the metal elements were cited from Liu et al. [2008]. "
    [Show abstract] [Hide abstract] ABSTRACT: [1] Previous studies have reported that atmospheric CO2 enrichment would increase the ion concentrations in the soil water. However, none of these studies could exactly quantify the amount of ions changes in the soil water induced by elevated CO2 and all of these experiments were carried out only in the temperate areas. Using an Open-Top Chamber design, we studied the effects of CO2 enrichment alone and together with nitrogen (N) addition on soil water chemistry in subtropics. Three years of exposure to an atmospheric CO2 concentration of 700 ppm resulted in accelerated base cation loss via leaching water below the 70 cm soil profile. The total of base cation (K++Na++Ca2++Mg2+) loss in the elevated CO2 treatment were higher than that of the control by 220%, 115%, and 106% in 2006, 2007, and 2008, respectively. The N treatment decreased the effect of high CO2 treatment on the base cation loss in the leachates. Compared to the control, N addition induced greater metal cation (Al3+ and Mn2+) leaching loss in 2008, and net Al3+ and Mn2+ loss in the high N treatment increased by 100% and 67%, respectively. However, the CO2 treatment decreased the effect of high N treatment on the metal cation loss. Changes of ion export following by the exposure to the elevated CO2 and N treatments were related to both ion concentrations and leached water amount. We hypothesize that forests in subtropical China might suffer from nutrient limitation and some poisonous metal activation in plant biomass under future global change.
    Full-text · Article · Apr 2014
    • "Treatments are: CK = control, NN = high N, CC = high CO 2 , CN = high CO 2 + high N. and Mg 2+ concentrations in leachates using inductively coupled plasma atomic emission spectroscopy. NO − 3 -N was determined by the phenol disulfonic acid spectrophotometric method (Nicholas and Nason, 1957) and NH + 4 -N by the indophenol blue spectrophotometric method (Horn and Squire, 1966). The P concentration was measured by the stannous chloride method (APHA Standard Methods, 20th ed., 4–145, Method 4500-P D, 1998). "
    [Show abstract] [Hide abstract] ABSTRACT: The effect of high atmospheric CO 2 concentra-tions on the dynamics of mineral nutrient is not well doc-umented, especially for subtropical China. We used model forest ecosystems in open-top chambers to study the effects of CO 2 enrichment alone and together with N addition on the dynamics of soil cations and anions. Two years of ex-posure to a 700 ppm CO 2 atmospheric concentration resulted in increased annual nutrient losses by leaching below 70 cm soil profile. Compared to the control, net Mg 2+ losses in-creased by 385%, K + by 223%, Ca 2+ by 167% and NO − 3 -N by 108%, respectively. Increased losses following exposure to elevated CO 2 were related to both faster weathering of minerals/organic matter decomposition and greater amounts of leaching water. Net annual nutrient losses in the high CO 2 concentration chambers reached 22.2 kg ha −1 year −1 for K + , 171.3 kg ha −1 year −1 for Ca 2+ , 8.2 kg ha −1 year −1 for Mg 2+ and about 2 kg ha −1 year −1 for NO − 3 -N. The N addition alone had no significant effect on the mineral nutrient leaching losses. However, addition of N together with the high CO 2 treatment significantly reduced mineral nutrient losses.We hypothesize that forests in subtropical China might suffer from nutrient limitation and reduction in plant biomass under elevated CO 2 concentration due to mineral leaching losses in the future.
    Full-text · Dataset · Mar 2013 · Soil Science and Plant Nutrition
    • "For the determination of total N and P content in plants, dried samples were digested with 4 mL H 2 SO 4 and 300 g L –1 H 2 O 2 in a Kjeldahl flask. Nitrogen was determined by spectrophotometer using the Indophenol blue method (Horn and Squire 1966) and P was determined by colorimeter using the vanadomolybdate yellow method (Bertramson 1942). "
    [Show abstract] [Hide abstract] ABSTRACT: We studied the effects of the application of organic matter (OM) and chemical fertilizer (CF) on soil alkaline phosphatase (ALP) activity and ALP-harboring bacterial communities in the rhizosphere and bulk soil in an experimental lettuce field in Hokkaido, Japan. The ALP activity was higher in soils with OM than in soils with CF, and activity was higher in the rhizosphere for OM than in the bulk soil. Biomass P and available P in the soil were positively related to the ALP activity of the soil. As a result, the P concentration of lettuce was higher in OM soil than in CF soil. We analyzed the ALP-harboring bacterial communities using polymerase chain reaction based denaturing gradient gel electrophoresis (DGGE) on the ALP genes. Numerous ALP genes were detected in the DGGE profile, regardless of sampling time, fertilizer treatment or sampled soil area, which indicated a large diversity in ALP-harboring bacteria in the soil. Several ALP gene fragments were closely related to the ALP genes of Mesorhizobium loti and Pseudomonas fluorescens. The community structures of the ALP-harboring bacteria were assessed using principal component analysis of the DGGE profiles. Fertilizer treatment and sampled soil area significantly affected the community structures of ALP-harboring bacteria. As the DGGE bands contributing to the principal component were different from sampling time, it is suggested that the major bacteria harboring the ALP gene shifted. Furthermore, there was, in part, a significant correlation between ALP activity and the community structure of the ALP-harboring bacteria. These results raise the possibility that different ALP-harboring bacteria release different amounts and/or activity of ALP, and that the structure of ALP-harboring bacterial communities may play a major role in determining overall soil ALP activity.
    Full-text · Article · Jan 2008
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