Nickel, determination

The use of peroxyacids, including PMSA, makes it possible to improve photometric method of nickel determination - to increase selectivity, accuracy and reproducibility of measurements. Peroxyacids as oxidants ai e used for nickel determination in aluminium and copper alloys, natural waters, stomatological products. 

It has been suggested that the rate limiting step in the mechanism is the chemisorption of propionaldehyde and that the hydrogen undergoes dissociative adsorption on nickel. Determine if the rate expression predicted by a Hougen-Watson model based on these assumptions is consistent with the experimentally observed rate expression. 

The results demonstrate that cadmium can be determined directly the direct determination of copper, manganese, and chromium is also possible, but their application is more limited than cadmium. The lead and nickel determination proved to be the most difficult, since their determination is limited by their low sensitivity and by the overlap of their absorption profiles with the background absorbance generated by seawater matrix. The direct determination of lead and nickel by this technique can be used only for seawater samples taken in coastal or estuarine zones that are quite polluted. 

Second, insertions are very selective, and the nature of the bond between organic groups and nickel determines the type of molecule which can be inserted. For example, allylic groups prefer to react with acetylene rather than with carbon monoxide (example 33, Table VII) but the opposite is true for benzyl or aryl groups. 7r-Lactonyl groups do not react either with carbon monoxide or acetylene, but they do react with ketones or aldehydes (example 39, Table VII). In this way sequential reactions take place on nickel with high selectivity. 

Sort through the information, first. You only need to know about the dimes and nickels. Determine the total of 20 rolls of nickels. Then figure out how many rolls of dimes you can get for that amount of money. Twenty rolls of nickels is 20 x 2 = 40. Divide 40 by 5 40 5 = 8 rolls of dimes. 

Schuphahn, I., Ballschmiter, K., Tolg, G. Use of polychlorous compounds for gas chromatographic determination of elements in the ng-level. I. Polychlorous xantho-genates and their use for nickel determination. Z. Anal. Chem. 255, 116 (1971). 

Nickel Determine as directed under Nickel Limit Test, Appendix IIIB, using a 20-g sample. 

Anhydro-D-glucose, Glucose and Sorbitol Transfer 30 mg of sample, accurately weighed, into a screw-cap vial, and add about 2 mL of pyridine. While flushing the vial with a stream of dry air or nitrogen, heat at 80° to 90° until the solution volume is reduced to 0.2 to 0.5 mL. Add a second portion of pyridine, and repeat the evaporation procedure. Continue as directed in the monograph for Polydextrose. Nickel Determine as directed under Nickel Limit Test, Appendix IIIB. 

Fig. 2. Improvement in linearity and sensitivity of nickel determination at higher resolution settings.

Metal-free sodium citrate buffer solution for iron and nickel determination, 1.0 M Dissolve 147 g of sodium citrate dihydrate plus 105 g of citric acid monohydrate in water and dilute to ca. 900 ml. Add 10 drops of bromphenol blue indicator solution (13) and adjust the pH to 4.7. 

If the total salt content of a solution is high or if only small amounts of sample are available the injection technique may be used. If a piston burette is used for the injection, individual errors cannot be avoided, and reproducibility becomes somewhat poorer than with continuous aspiration. Also, the uncertainty of the volume measurement with small injection volumes becomes noticeable in the reproducibility. In Table 4 the data and statistical values of a simultaneous copper and nickel determination are shown. 

Table 2 Concentration of chromium and nickel, determined by AAS, in samples taken from four sources of waste waters...

S. Schiefer, M. Huth, A. Dobrinevski, and B. Nickel, Determination of the Crystal Structure of Substrate-Induced Pentacene Polymorphs in Fiber Structured Thin Films, J. Am. Chem. Soc. 129, 10316-10317(2007). 

Nickel is determined by the gravimetric dimethyl-glyoxime procedure after reduction of the compound with sulfur dioxide and hydrochloric acid. Iodine is determined as silver iodide after reduction with sulfur dioxide in sulfuric acid medium. Total active oxygen is calculated by measuring the quantity of iodine liberated from potassium iodide in acidic solution. Alkali metals are determined as sulfates in the filtrates from the nickel determinations. 

Second, the values of bond energies of hydrogen, carbon, and nitrogen with nickel determined according to the second variant of the kinetic method practicallj- coincide with those obtained much earlier by the independent combined thermochemical and comparative method (Table XIV). 

Analytical Methods and Speclatlon Electrothermal atomic absorption spectrophotometry (ETAAS), differential pulse adsorption voltammetry (DPAV), isotope-dilution mass spectrometry (ID-MS), and inductively coupled plasma mass spectrometry (ICP-MS) furnish the requisite sensitivity for measurements of nickel concentrations in biological, technical and environmental samples (Aggarwal et al. 1989, Case et al. 2001, Stoeppler and Ostapczuk 1992, Templeton 1994, Todorovska et al. 2002, Vaughan and Templeton 1990, Welz and Sperling 1999). The detection limits for nickel determinations by ETAAS analysis with Zeeman background correction are approximately 0.45 jg for urine,... 

Nickel determination by flameless A AS (graphite tube technique)... 

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