Indirect fluorescence detection of free cyanide and related compounds by capillary electrophoresis
1995; Elsevier BV; Volume: 709; Issue: 2 Linguagem: Inglês
10.1016/0021-9673(95)00446-t
ISSN1873-3778
AutoresVicenç Martí, M. Aguilar, Edward S. Yeung,
Tópico(s)Electrochemical Analysis and Applications
ResumoA capillary electrophoretic method to detect CN− and some related compounds (CNO−, SCN−, and NO3−) using a prototype laser-based indirect fluorescence detector has been developed. This method avoids interferences from Cl−, SO42−, CO32−, HCO3−, and ClO− and allows the detection of CN− in less than 4 min and the detection of related compounds in less than 8 min with precise migration times (R.S.D. about 1%). The measured detection limits of CN− [5 × 10−6 M with DR = 90 (dynamic reserved)] are close to the expected theoretical value [TRCN = 0.44 (transfer ratio)]. For the related compounds, the measured detection limits ranged from 10−5 to 2 × 10−6 M, depending on noise conditions (DR ⩾ 300). The results showed that the chosen analytical conditions were appropriate and the detection limits could be improved using techniques to further decrease the noise (probably due to mechanical vibrations). Peak-height precision was about 10% R.S.D. and log-log regressions had slopes lower than one. These results seem to be due to instabilities in the indirect signal. The analysis of a quasi-real sample has been achieved, allowing identification of the related compounds present in a CN−/SCN− sample oxidized with ClO− and determination of the CNO− formed in this alkaline oxidation.
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