Ammonium citrate analysis

The methods of analysis for phosphate solubility are not absolute, but empirical that is, they are based on practical experience. For example, the neutral ammonium citrate method is favoured in the USA because it has received over 100 years of study and experimentation, and provides an index correlating the laboratory results with the fertilizing value of water-insoluble phosphates under the conditions prevailing in the principal farming regions of the country. The particular solvent is therefore not an attempt to accurately reproduce the properties of the soil solution in the immediate vicinity of the... 

The Sequazyme C-peptide sequencing kit enables peptide digestion followed by analysis of sequentially truncated peptides using MALDI-TOF-MS. Before digesting and analyzing unknown samples of the peptide (adrenocorticotropic hormone), the activity of the enzyme carboxypeptidase Y (CPY) was checked by dilution experiments with ammonium citrate buffer (pH = 6.1), CPY dilution and the peptide standard angiotensin I. The adrenocorticotropin ACTH (18-39) fragment (0.3 pL) was transferred as a solution of 5 x 10 5M in a 1 1... 

Approximately 75 ml solution was used for the analysis. Buffering was performed with ammonium citrate at pH 9, followed by addition of 0.5 ml of 0.25 mol 1 diethyldithiocarbamate. Extraction was carried out with 5 ml pentane. The extract was dried with Na2S04, evaporated to 0.5 ml and redissolved into hexane. Derivatization involved the addition of 0.5 ml of 2mol BuMgCl in THE, followed by addition of H2SO4.Separation was by CGC (fused-silica column of 60 m length. 

Ferric ammonium citrate (C6H607Fe.C6H60r(NH4)2H), is used in making blue-print paper (242). A strong solution of neutral ammonium citrate is used in the analysis of fertilizers in the separation of the different forms of phosphates which the fertilizers contain. 

ESCA analysis of ammonium citrate and HTTHG treated steel is currently being undertaken in an attempt to better understand the chemical processes which are occuring at the surface. The following proposal is presented in an attempt to explain the bond improvement mechanism. As stated earlier, the ammonium citrate pretreatraent was found to be a necessary component of the treatment. Citric acid is known to be an effective treatment for the removal of iron oxide from stainless steel... 

Direct AP methods involve the determination of citrate-soluble P2O5 by direct AP analysis after the water-soluble portion is removed. The failure to remove the water washing step before addition to the neutral ammonium citrate will result in oversaturation of the ammonium citrate, resulting in low results. Generally, direct methods are less precise and results have a higher standard deviation. Problems encountered with direct methods are technique, interference of ammonium citrate in the spectrophotometric method, and not using proper acid digestion methods. 

Joulie s and Petermann s solutions are alkaline ammonium citrates containing free ammonia. Solvent compositions, extraction methods, ratios of sample to solvent, and methods for analysis are specified for each solvent. 

A MALDI-MS study of DNA analysis using 2,4,6-THAP and 2,3,4-trihydroxyaceto-phenone (2,3,4-THAP), separately and in combination, was performed. The results showed that a mixture of 2,3,4-THAP, 2,4,6-THAP, and ammonium citrate with molar ratios of 2 1 1 serves as a good matrix for the detection of DNA, especially for samples containing a small quantity of DNA such as PCR products. The resolution and shot-to-shot reproducibility using this matrix combination were better than, and the MALDI sensitivity comparable to, that obtained when using 3-HPA, PA, and ammonium citrate matrix (9 1 1). 

Calcium, iron, magnesium, alkali metals, and citrates do not affect the analysis. Ammonium salts interfere and must be eliminated by means of sodium nitrite or sodium hypobromite. The hydrochloric acid normally used in the analysis may be replaced by an equivalent amount of nitric acid without any influence on the course of the reaction. Sulphuric acid leads to high and erratic results and its use should be avoided. 

Widespread medicinal use of colloidal bismuth subcitrate (CBS) has prompted extensive studies of bismuth compounds involving the citrate anion. Bismuth citrate is essentially insoluble in water, but a dramatic increase in solubility with increasing pH has been exploited as a bio-ready source of soluble bismuth, a material referred to as CBS. Formulation of these solutions is complicated by the variability of the bismuth anion stoichiometry, the presence of potassium and/ or ammonium cations, the susceptibility of bismuth to oxygenation to Bi=0, and the incorporation of water in isolated solids. Consequently, a variety of formulas are classified in the literature as CBS. Solids isolated from various, often ill-defined combinations of bismuth citrate, citric acid, potassium hydroxide, or ammonium hydroxide have been assigned formulas on the basis of elemental analysis data or by determination of water and ammonia content, but are of low significance in the absence of complementary data other than thermal analysis (163), infrared spectroscopy (163), or NMR spectroscopy (164). In this context, the Merck index lists the chemical formula of CBS as KgfNHJaBieOafOHMCeHsCbh in the 11th edition (165), but in the most recent edition provides a less precise name, tripotassium dicitrato bismuthate (166). 

For Tc labelled peptides, ITLC-SG analysis was accomplished using three different mobile phases 2-Butanone to determine the amount of free TcO (Rf = 1), O.IM sodium citrate at pH5 to determine Tc coligand and TCO4 (- f = 1)> and methanoklM ammonium acetate (1 1 vol./vol.) to determine Tc-colloid (Rf = 0). The Rf values of the radiolabelled peptide in each system were 0.0,0.0 and 0.7-1.0, respectively. 

For the analysis of ammonium, the sample carrier stream consists of 10 mM NaOH + 0.2 M Na-citrate. This converts ammonium into NH -gas which penetrates the PTFE membrane and travels into the gas receiver stream, in this case consisting of 50 pm HCl. Here as well, an electric conductivity cell is used for the measurements. To provide a steady and impulse-free flow of the solutions, a multichannel peristaltic pump is used. The flow rates in both cases were set to approx. 

Bayot et al. [70] prepared and characterized ammonium derivatives of molybdenum(VI) complexes of general formula (NH4)2[MoO(02)2(HxL)] nH20 and (NH4)2[Mo02(C>2)(L)] widi L=oxalate, citrate, tartrate, glycolate and malate on the basis of elemental and thermal analysis as well as by IR and NMR spectroscopy. 

CZE separation of synthetic dyes has been approached by simple (borate and citrate) and volatile buffers (ammonium acetate) modified by solvents as well as nonaqueous systems (ammonium acetate/acetic acid in MeOH). Environmental applications of CZE methodologies include the analysis of spent dyebaths and wastewater samples and the monitoring of groundwater migration, where eosin was used as a fluorescent tracer (details in Table 31.8). ... 

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