Determination of nitrite in waters by microplate fluorescence spectroscopy and HPLC with fluorescence detection.
A selective and versatile fluorescence spectroscopic method for the determination of nitrite in waters has been developed. Nitrite reacts in the presence of mineral acids with the nonfluorescent N-methyl-4-hydrazino-7-nitrobenzofurazan forming N-methyl-4-amino-7-nitrobenzofurazan, which can be detected by fluorescence spectroscopy with an excitation maximum at lambda = 468 nm and an emission maximum at lambda = 537 nm in acetonitrile. Three new methods based on this reaction have been developed: Direct fluorescence spectroscopy, HPLC/fluorescence, or HPLC with UV/vis detector may be selected as detection techniques. On microplates, high-throughput fluorescence spectroscopy is achieved, while HPLC/fluorescence provides lower limits of detection, and HPLC with UV/vis detection enables evaluation of the reaction with standard instrumentation. Different water samples were investigated using all detection modes, and a photometric standard procedure was successfully employed to validate the new methods with an independent technique.
Büldt
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A
Abteilung Analytische Chemie, Westfälische Wilhelms-Universität Münster, Germany.
Karst
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U
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005453:Fluorescence; D006834:Hydrazines / Q000737:chemistry; D015394:Molecular Structure; D009573:Nitrites / Q000032:analysis*; D010069:Oxadiazoles / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods*; D014466:Ultraviolet Rays; D014867:Water / Q000032:analysis*
D006834:Hydrazines; C121459:N-methyl-4-amino-7-nitrobenzofurazan; C121458:N-methyl-4-hydrazino-7-nitrobenzofurazan; D009573:Nitrites; D010069:Oxadiazoles; D014867:Water