Determination of tetracycline hydrochloride in presence of anhydrotetracycline by differential pulse polarography

Flow Injection Spectrophotometric Determination of Tetracycline in a Pharmaceutical Preparation by Complexation with Aluminium(III)

A rapid flow injection (FI) spectrophotometric procedure for tetracycline determination is described. It is based on the injection of a 100 microl sample solution containing tetracycline into merged streams of aluminium(III) chloride (0.01 mol 1(-1)) and Tris-buffer in the presence of KCl (0.06 mol l(-1)), pH 7.0, with the same optimum flow rate of 3.2 ml min(-1). A yellow Al(III)-tetracycline complex was monitored at 376 nm. The flow injection system and the experimental conditions were optimized by means of the univariate method. The procedure was applied to the determination of tetracycline in pharmaceutical preparations with a high sampling rate of at least 165 h(-1). A high precision with a relative standard deviation was obtained less than 0.72 and 0.30% of 5.0 and 10 microg ml(-1) (n=11), respectively. The detection limit (3sigma) and the quantification limit (10sigma) were 0.07 and 0.72 mg l(-1), respectively. There were no interference effects from traditional excipients in the dosage forms when the method was applied to pharmaceutical preparations. The matrix effect could be reduced by the standard addition method.

Electroanalysis of Tetracycline Using Nickel-implanted Boron-doped Diamond Thin Film Electrode Applied to Flow Injection System

The electrochemical analysis of tetracycline was investigated using nickel-implanted boron-doped diamond thin film electrode by cyclic voltammetry and amperometry with a flow injection system. Cyclic voltammetry was used to study the electrochemical oxidation of tetracycline. Comparison experiments were carried out using as-deposited boron-doped diamond thin film electrode (BDD). Nickel-implanted boron-doped diamond thin film electrode (Ni-DIA) provided well-resolved oxidation irreversible cyclic voltammograms. The current signals were higher than those obtained using the as-deposited BDD electrode. Results using nickel-implanted boron-doped diamond thin film electrode in flow injection system coupled with amperometric detection are presented. The optimum potential for tetracycline was 1.55 V versus Ag/AgCl. The linear range of 1.0 to 100 microM and the detection limit of 10 nM were obtained. In addition, the application for drug formulation was also investigated.

Analysis of Tetracycline Antibiotics Using HPLC with Pulsed Amperometric Detection

The analysis of tetracycline, oxytetracyline, chlortetracycline and doxycycline by high-performance liquid chromatography with pulsed amperometric detection using an anodized boron-doped diamond thin film (BDD) electrode is originally reported. The analyses were carried out using the mobile phase, phosphate buffer (0.01 M, pH 2.5)-acetonitrile (80:20; v/v), on a C18 column (250 x 4.6 mm i.d., 5 microm) at a flow rate of 1.0 mL/min. The optimal PAD waveform parameters at the anodized BDD were 1.5 V (versus Ag/AgCl) detection potential (E(det)) for 290 ms (200 ms delay time and 90 ms integration time), 2.0 V (versus Ag/AgCl) oxidation potential (E(oxd)) for 200 ms oxidation time (t(oxd)) and 0.4 V (versus Ag/AgCI) reduction potential (E(red)) for 200 ms reduction time (t(red)). The proposed method showed the simultaneous determination of tetracycline, oxytetracyline, chlortetracycline and doxycycline with a linear range of 0.1 - 100 microg/mL, detection limits of 0.05 - 0.1 microg/mL and recoveries of 70.8 - 96.0%. The application of this method to real samples was demonstrated and validated using a shrimp sample.

Application of the computerized compensation method and the orthogonal functions method to correct for irrelevant interference in spectrofluorometry

The computerized compensation method and the orthogonal functions method were applied to correct for the presence of interferences in spectrofluorometric analysis. The methods were demonstrated by the determination of tetracycline (TC) and anhydrotetracycline (ATC) in combination. The calibration graphs were linear in the concentration range 0.02-0.12 mg/100 ml of either TC or ATC.