H. Pasekova et al., Determination of some sulphonamides by sequential injection analysis with chemiluminescence detection, ANALYT CHIM, 438(1-2), 2001, pp. 165-173
Determination of a group of sulphonamides (sulphanilamide, sulphacetamide,
sulphathiazole, sulphadimidine, sulphafurazole, sulphamethoxypyridazine, su
lphaguanidine) using sequential injection analysis (SIA) technique with che
miluminescence (CL) detection has been devised. The CL signal was emitted d
uring the oxidation of sulphonamides by potassium permanganate in sulphuric
acid medium. The lab-made SIA system consisted of a 2.5 mi Cavro syringe p
ump, eight-port Vici Valco selection valve and a lab-modified Spectra-Physi
cs FS 970 fluorescence detector. It was controlled by a PC with use of orig
inally compiled LabVIEW((R))-suppotted software. Concentration, volume of r
eagents and Row rate were optimised by a simplex method. A number of enhanc
ers was tested to increase the CL signal. The optimum conditions and sequen
ce of injected zones for sulphanilamide (model substance) were: 0.1 M gluta
raldehyde 45 mul, sample 50 mul; 0.5 M H2SO4 45 mul; 1 mM KMnO4 46 mul and
100 mul s(-1) Row rate. The transient CL signal (lambda greater than or equ
al to 390 nm) was recorded after a single reversal of the flow. Calibration
curves relating the intensity of CL (peak heights) to the concentration of
the analytes were curvilinear (of the second polynomial order) with rectil
inear sections typically in the range approximate to0.01-0.5 mM sulphonamid
e. The sample throughput was 120 h(-1). The proposed method has been applie
d for the assay of sulphacetamide and sulphafurazole in pharmaceutical dosa
ge forms. The SIA results did not show any statistically significant differ
ence from those obtained by titrimetry according to USP XXIV. (C) 2001 Else
vier Science B.V. All rights reserved.