Oxygen, determination accuracy

As shown in a certification round organized within BCR, different methods can be used to determine oxygen in nickel with a precision and accuracy better than 10 % at the 10 Mg/g level (242). Table VII-28 summarizes the results obtained for oxygen in BCR-CRM No.99 (certified value ... 

Accuracy. Precision and Conditions for Thermal and Fast NAA for Al. Cl Mn Determination of Pellet Weight and of the Copper/Oxygen Ratio to... 

Applications Basic methods for the determination of halogens in polymers are fusion with sodium carbonate (followed by determination of the sodium halide), oxygen flask combustion and XRF. Crompton [21] has reported fusion with sodium bicarbonate for the determination of traces of chlorine in PE (down to 5 ppm), fusion with sodium bisulfate for the analysis of titanium, iron and aluminium in low-pressure polyolefins (at 1 ppm level), and fusion with sodium peroxide for the complexometric determination using EDTA of traces of bromine in PS (down to 100ppm). Determination of halogens in plastics by ICP-MS can be achieved using a carbonate fusion procedure, but this will result in poor recoveries for a number of elements [88]. A sodium peroxide fusion-titration procedure is capable of determining total sulfur in polymers in amounts down to 500 ppm with an accuracy of 5% [89]. 

Fluorine flame calorimetry is a logical extension of oxygen flame calorimetry in which a gas is burned in excess of gaseous oxidant (214). The decision does not reach that of the oxygen flame calorimeter in which, for example, Affj(H20) was determined with a standard deviation of 0.01%. Combustions of H2, NH3 (8), and fluorinated hydrocarbons are typical applications, but the uncertain nonideality corrections of HF(g) prevent full realization of the inherent accuracy. 

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