摘要:

A sensitive spectrophotometric method for the determination of nitrogen dioxide in air and nitrite in water and soil samples is described. Nitrogen dioxide in air is fixed as nitrite ion in alkaline sodium arsenite or in triethanolamine absorber solutions. The method is based on the diazo coupling reaction between p-nitro aniline and 1-hydroxy-2-naphthoic acid. The azo dye formed under aqueous condition has an absorption maximum at 585nm and obeys Beer's law over the range 0–25μg of nitrite. The colour system is stable for 72h. The relative standard deviation is 2.7% for ten determinations at 15μg of nitrite. The dye is extracted with 1:1 isoamyl alcohol-IBMK mixture and stabilisation with methanolic potassium hydroxide showed λmaxat 610nm. It obeys Beer's law over the range 0–4μg of nitrite. The colour system is stable for 40h in organic phase and the relative standard deviation is 2.5% for ten determinations at 3μg of nitrite The molar absorptivity of the colour system is 3.68 × 104Lmol−1cm−1. The effect of interfering gases and other ions on the determination of nitrite is described. The developed method has been applied for the determination of residual nitrogen dioxide gas present in the laboratory fume cupboard and automobile exhaust gases. In addition, the method has been applied for the determination of nitrite and nitrate in samples like water, soil and radiator coolants.

ISSN:0003-2719    

DOI:10.1080/00032719508001114

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The extraction behavior of rare earths has been studied with di-(2-ethylhexyl)phosphoric acid (DEHP) in paraffin, naphthalene, and biphenyl. The group separation of rare earths with DEHP was further examined in paraffin. In the presence of 0.3 mol/L HNO3and 2.0 mol/L DEHP, light rare earths can be separated from heavy ones in rare earth ores. Quantitative analysis of the rare earths was then done by spectrophotometry.

ISSN:0003-2719    

DOI:10.1080/00032719508001115

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719508001103

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor