Dispersive liquid-liquid microextraction coupled to liquid chromatography tandem mass spectrometry for the determination of phenolic compounds in human milk.

This work describes a novel approach for the analysis of 11 phenolic compounds (naringenin, hesperetin, kaempferol, quercetin, epicatechin, epicatechin gallate, epigallocatechin gallate, genistein, daidzein, caffeic acid, gallic acid) in human milk. Clean-up of the sample and extraction of 11 analytes from milk was performed by dispersive liquid-liquid microextraction (DLLME). Under the optimal conditions, the extraction recoveries of 11 analytes were in a range from 94.

Application of direct-injection detector integrated with the multi-pumping flow system to chemiluminescence determination of the total polyphenol index.

In this work, we present a novel chemiluminescence (CL) method based on direct-injection detector (DID) integrated with the multi-pumping flow system (MPFS) to chemiluminescence determination of the total polyphenol index. In this flow system, the sample and the reagents are injected directly into the cone-shaped detection cell placed in front of the photomultiplier window. Such construction of the detection chamber allows for fast measurement of the CL signal in stopped-flow conditions immediately after mixing the reagents.

Determination of the total polyphenolic content in Cirsium palustre (L.) leaves extracts with manganese(IV) chemiluminescence detection.

It was found that weak chemiluminescence of manganese(IV)-hexametaphosphate-formaldehyde system was greatly enhanced by plant polyphenolic compounds. Based on this finding, a new flow injection chemiluminescence method (FI-CL) was developed for the determination of the total content of polyphenols in plant extracts. The calibration graph obtained for standard solutions of 6-hydroxyluteolin 7-O-glucoside (6OHLG) was linear in the range 0.

Determination of the flavonoids/antioxidant levels in Cirsium oleraceum and Cirsium rivulare extracts with cerium(IV)-rhodamine 6G chemiluminescence detection.

The determination of the sum of flavonoid compounds in extracts from inflorescences (expressed as mgL(-1) of apigenin) and leaves (expressed as mgL(-1) of linarin) of Cirsium oleraceum and Cirsium rivulare species by flow injection system with chemiluminescence detection (FI-CL) has been carried out. The method is based on the strong enhancement by polyphenols occurring in both plants of the CL signal generated by the reaction of cerium(IV) with rhodamine 6G in a sulfuric acid medium. Under the optimized conditions, the linear working ranges of 0.

Sorption of platinum on immobilized microorganisms for its on-line preconcentration and chemiluminescent determination in water samples.

Fungi of the type Aspergillus sp. were immobilized on a cellulosic resin and used as a biosorbent for the on-line preconcentration and separation of Pt(IV) ions prior to their chemiluminescent determination via flow injection analysis. Biosorption and elution conditions were optimized, and the results compared to biosorbents based on the use of Chlorella vulgaris algae and Saccharomyces cerevisiae yeast in terms of preconcentration and selective retention of Pt(IV).

Flow injection chemiluminescence determination of the total phenolics levels in plant-derived beverages using soluble manganese(IV).

This study established a flow injection (FI) methodology for the determination of the total phenolic content in plant-derived beverages based on soluble manganese(IV) chemiluminescence (CL) detection. It was found that mixing polyphenols with acidic soluble manganese(IV) in the presence of formaldehyde evoked chemiluminescence. Based on this finding, a new FI-CL method was developed for the estimation of the total content of phenolic compounds (expressed as milligrams of gallic acid equivalent per litre of drink) in a variety of wine, tea and fruit juice samples.

A novel flow-injection method for the determination of Pt(IV) in environmental samples based on chemiluminescence reaction of lucigenin and biosorption.

A new flow-injection chemiluminescence method (FI-CL) was developed for the determination of trace amounts of Pt(IV). The method is based on the quenching effect of the analyte on CL emission generated by lucigenin in alkaline solution. Application of a column filled with an algae Chlorella vulgaris immobilized on Cellex-T resin allowed to preconcentrate and separate the Pt(IV) ions from complex environmental samples, such as road dust.

Determination of phenolic compounds and their antioxidant activity in Erigeron acris L. extracts and pharmaceutical formulation by flow injection analysis with inhibited chemiluminescent detection.

It was found that the chemiluminescence (CL) produced from the reaction of luminol with iodine in the alkaline medium was strongly inhibited by plant phenolic compounds. Based on this finding, a new flow injection CL method was developed for the determination of caffeic acid and 6'-caffeoylerigeroside. The latter compound was isolated for the first time from Erigeron acris L.

Determination of catecholamines by flow-injection analysis and high-performance liquid chromatography with chemiluminescence detection.

A chemiluminescence (CL) detection of catecholamines [norepinephrine (NE), epinephrine (E), dopamine (DA) and L-dopa (LD)] is described for the flow-injection (FI) and high-performance liquid chromatographic (HPLC) determination of these compounds. The detection method is based on the inhibition effect of catecholamines (CAs) on the CL reaction of luminol with iodine in the alkaline medium. The proposed FI method allows the determination of CAs in pharmaceutical preparations for the purpose of drug quality control.

Determination of dopamine by flow-injection analysis coupled with luminol-hexacyanoferrate(III) chemiluminescence detection.

A novel flow-injection method (FIA) for the determination of dopamine based on the inhibition of the intensity of chemiluminescence (CL) from luminol-hexacyanoferrate(III) system in basic medium is described. The present method allows the determination of dopamine over the range 30-100 microg l(-1) and 400-3000 microg l(-1). The relative standard deviation is 2.

Studies and analytical application of reaction of imipramine with chrome azurol S.

Chrome azurol S (CAS) was tested as a spectrophotometric reagent for the determination of imipramine (IMP). It reacts in aqueous media with IMP forming pink-red, sparingly soluble in water ion association compound. This compound was quantitatively extracted with chloroform and the absorbance of organic phase was measured at 510 nm.