Determination of Biogenic Amines at Low µg L-1 Levels as Acetylacetone Derivatives by RP-HPLC with UV-Visible Detection in Expired Apple Juice Samples.

An accurate and sensitive method for trace quantification of three biogenic amines in expired apple juice samples based on reversed-phase liquid chromatography (RP-HPLC) with UV-visible detection is described. Biogenic amines including cadaverine, histamine, and tyramine, were converted to their acetylacetone derivatives in water-methanol medium. The proposed method involves a pre-column derivatization of species followed by RP-HPLC separation with Thermo Hypersil Gold reversed-phase column and UV detection at 315 nm.

A very sensitive flow-injection spectrophotometric determination method for iron (II) and total iron using 2', 3, 4', 5, 7-pentahydroxyflavone.

In this study, an ultra-sensitive and highly selective, rapid flow-injection spectrophotometric method for the determination of iron (II) and total iron has been proposed. The method was based on the reaction between iron (II) and 2', 3, 4', 5, 7-pentahydroxyflavone in slightly acidic solution with a strong absorption at 415 nm. The carrier solution used was 1 × 10(-5) M 2', 3, 4', 5, 7-pentahydroxyflavone in 0.

A simple and selective flow-injection spectrophotometric determination of copper(II) by using acetylsalicylhydroxamic acid.

A new simple, and rapid flow-injection spectrophotometric method is developed for the determination of trace amounts of Cu(II) by using a new chromogenic reagent acetylsalicylhydroxamic acid (AcSHA). The method is based on the formation of colored Cu(II)-(AcSHA)(2) complex. The optimum conditions for the chromogenic reaction of Cu(II) with AcSHA is studied and the colored (green) complex is selectively monitored at lambda(max) 700 nm.

Spectrophotometric flow-injection analysis of mercury(II) in pharmaceuticals with p-nitrobenzoxosulfamate.

A new, simple and rapid spectrophotometric FI method for the accurate and precise determination of Hg(II) in pharmaceutical preparations has been developed. The method is based on the measuring the decrease of absorbance intensity of p-nitrobenzoxosulfamate (NBS) due to the complexation with Hg(II). The absorption peak of the NBS, which is decreased linearly by addition of Hg(II), occurs at 430 nm in 2x10(-4) moll(-1) HNO(3) as a carrier solution.

A simple flow-injection spectrofluorimetric method for the determination of mercury.

A highly sensitive flow-injection spectrofluorimetric method is presented for the rapid and simple determination of Hg (II) in environmental and pharmaceutical samples. Murexide (ammonium purpurate) was used as the fluorescence reagent in the carrier stream. An emission peak of murexide, which is decreased linearly by addition of Hg (II), occurs at 435 nm in aqueous solution with excitation at 335 nm.

Flow-injection spectrophotometric determination of nanogram levels of iron(III) with N,N-dimethylformamide.

A simple and fast flow-injection spectrophotometric method has been described for the determination of iron(III). The method is based on the measurement of absorbance intensity of the complex that is formed between iron(III) and N,N-dimethylformamide (DMF) at 310 nm. The carrier stream was just a mixture of water and DMF at ratio 5% (v/v).

Determination of major phenolic compounds in water by reversed-phase liquid chromatography after pre-column derivatization with benzoyl chloride.

A simple reversed-phase LC method capable of detecting ng/ml quantities of phenolic compounds in water is described. Pre-column derivatization with benzoyl chloride is used for the separation and determination o-cresol, m-cresol, p-cresol, phenol, resorcinol, catechol and hydroquinone in water. The benzoyl derivatives formed within in 15 min, were extracted with dietyl ether, and then analyzed by liquid chromatography with UV detection at 232 nm.