Rapid spectrophotometric determination of benzalkonium in pharmaceuticals by extraction/ FIA
Bivalent BPB anion reacts with 10-5 M quinine in neutral media to form a 1:2 charge transfer complex in 1, 2-dichloroethane, but not with 10-6 M benzalkonium. However, trace amounts of benzalkonium could be extracted into 1, 2-dichloroethane with BPB only when 10-410-5 M quinine was added in the ext...
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Published in | BUNSEKI KAGAKU Vol. 39; no. 2; pp. 73 - 77 |
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Main Authors | , , |
Format | Journal Article |
Language | Japanese English |
Published |
Tokyo
The Japan Society for Analytical Chemistry
1990
Japan Science and Technology Agency |
Subjects | |
Online Access | Get full text |
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Summary: | Bivalent BPB anion reacts with 10-5 M quinine in neutral media to form a 1:2 charge transfer complex in 1, 2-dichloroethane, but not with 10-6 M benzalkonium. However, trace amounts of benzalkonium could be extracted into 1, 2-dichloroethane with BPB only when 10-410-5 M quinine was added in the extraction system giving a blue product. The molar absorptivity of the product was 50500 mol-1cm-1l at 610 nm. The blue product can be used for selective and rapid spectrophotometric determination of benzalkonium by the FIA method. The carrier solution (0.8 M phosphate buffer, pH 7.5) was pumped at a 0.75 ml/min flow rate and 1×10-4 M quinine standard solution and 5×10-5 M BPB were pumped at 0.25 ml/min each. Sample solutions (100 μl) were injected into the carrier stream by a six-way injection valve and mixed with the reagents in a 1 m reaction coil. The ion associate formed by quinine, BPB and benzalkonium was extracted into the organic phase in a 4 m extraction coil. The organic phase was separated by a phase separator with either a microporous polytetrafluoroethylene (PTFE) membrane (pore size 0.5 μm) or PTFE tubing (pore size 2 μm), and put through a 8-μl flow cell. Then the absorbance was measured at 610 nm and recorded as peak-shaped signals. Benzalkonium in the range of 5×10-6 M to 1.5×10-4 M could be determined and the relative standard deviation was 1.1% for 10 determinations of 1×10-4 M benzalkonium. The sample throughput was 24/h. The FIA method proposed here can be applied to the selective and rapid assay of benzalkonium in pharmaceuticals. |
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ISSN: | 0525-1931 |
DOI: | 10.2116/bunsekikagaku.39.2_73 |