A spectrometric, separation and voltammetric study of the complexation reactions of bromazepam with iron(ii),copper(ii) and cobalt(ii)
1982; Elsevier BV; Volume: 141; Linguagem: Inglês
10.1016/s0003-2670(01)95336-x
ISSN1873-4324
AutoresW.F. Smyth, R. A. Scannell, T.K. Goggin, D. Lucas-Hernández,
Tópico(s)Analytical chemistry methods development
ResumoBromazepam, in the form of a cationic iron(II) chelate, can be determined spectrophotometrically at 588 nm with a limit of detection of ca. 10-6 M. When this chelate is ion-paired with perchlorate, it can be extracted into organic solvents such as 1,2-dichloroethane and 4-methyl-2-pentanone, and determined by atomic absorption spectrometry with a limit of detection of 1.5 × 10-5 M bromazepam at the iron resonance 248.3-nm line. Ion-pairs involving the Fe(II), Cu(II) and Co(II) chelates and perchlorate can be separated by h.p.l.c. using a C18 reverse-phase column and a mobile phase of 4:1 water—methanol, with a u.v. detector at 242 nm. This approach allowed for the determination of iron(II) ions in aqueous solution with a limit of detection of 10-8 M. The h.p.l.c. method could also be used to quantify bromazepam spiked in plasma in the concentration range 1–10 μg ml-1, following extraction of bromazepam from plasma and subsequent formation of the iron(II) ion-pair. Copper(II) forms a labile chelate with bromazepam in pH 4.8 acetate buffer which, when subjected to differential pulse voltammetry at the hanging mercury drop electrode, gives rise to a catalytic phenomenon which can be utilised for the determination of bromazepam in the concentration range 10-5–10-9 M.
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