Flow-Injection Chemiluminescence Determination of Formaldehyde with a Bromate-Rhodamine 6G System

New chemiluminescent method of levofloxacin and ofloxacin determination based on terbium (III)-sensitized fluoroquinolone-KBrO3 reaction

Fluoroquinolones can be oxidized with some agents, in this study selected fluoroquinolones (levofloxacin, ofloxacin, ciprofloxacin, norfloxacin, pefloxacin and enrofloxacin) were oxidized with potassium bromate in the presence of terbium (III) ions. According to the kinetic and spectral analysis of chemiluminescence emitted by the above systems, the terbium (III) ions were the only emitter. The excitation of the lanthanide ion was a result of the process of energy transfer from the products of fluoroquinolones oxidation to Tb(III) ions. The highest intensity of chemiluminescence was obtained for levofloxacin and ofloxacin containing an alkoxy substituent at C-8 in the quinoline ring. The chemiluminescence intensity was correlated linearly (r = 0.9994) with the concentration of ofloxacin (or levofloxacin) in the range 1 × 10^-6 to 4 × 10^-5 mol L^-1 ; the detection limit was 3 × 10^-7 mol L^-1 for both fluoroquinolones. In the optimized conditions, the chemiluminescence of the levofloxacin (or ofloxacin)-Tb(III)-KBrO₃ -H₂ SO₄ systems was used to determine these compounds in a mixture of fluoroquinolones and in pharmaceuticals.

A simple and sensitive flow injection method based on the catalytic activity of CdS quantum dots in an acidic permanganate chemiluminescence system for determination of formaldehyde in water and wastewater

The intensity of emitted light from KMnO₄–HCHO–CdS QDs system is linearly proportional to HCHO concentration.

Flow Injection Determination of Formaldehyde by Its Catalytic Effect on the Oxidation of Sulfonazo III by Bromate with Spectrophotometric Detection

A simple and sensitive flow injection method with spectrophotometric detection was developed for the determination of formaldehyde. The method is based on the catalytic effect of formaldehyde on the oxidation of sulfonazo III with bromate in acidic media. The decrease in absorbance of the reaction mixture was measured at 566 nm. The calibration graph was linear in the range of 0.005 to 2.80 microg ml(-1) formaldehyde at a rate of 38 +/- 4 samples h(-1). The limit of detection was 4 ng ml(-1). The relative standard deviations for ten replicate measurements of 0.20, 0.50 and 1.00 microg ml(-1) formaldehyde were 1.3, 0.8 and 0.7%, respectively. The method was applied to the determination of formaldehyde in river water, shampoo and melamine-formaldehyde resin.