A sensitive and selective method for the determination of flumorph residues in vegetables and fruits by HPLC-ESI-MS/MS.

A method has been developed and validated for the quantitative determination of flumorph residues in vegetables and fruits using dimoxystrobin as internal standard (I.S.) by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Sequential injection kinetic spectrophotometric determination of quaternary mixtures of carbamate pesticides in water and fruit samples using artificial neural networks for multivariate calibration.

A new analytical method was developed for the simultaneous kinetic spectrophotometric determination of a quaternary carbamate pesticide mixture consisting of carbofuran, propoxur, metolcarb and fenobucarb using sequential injection analysis (SIA). The procedure was based upon the different kinetic properties between the analytes reacted with reagent in flow system in the non-stopped-flow mode, in which their hydrolysis products coupled with diazotized p-nitroaniline in an alkaline medium to form the corresponding colored complexes. The absorbance data from SIA peak time profile were recorded at 510 nm and resolved by the use of back-propagation-artificial neural network (BP-ANN) algorithms for multivariate quantitative analysis.

[Determination of sulfur dioxide in air by sequential injection spectrophotometry].

A sequential injection spectophotometric method for the determination of sulfur dioxide by decolorizing malachite green in an alkali medium is studied; the decreasing in color is proportional to the amount of sulfur dioxide. The loading sequence, the concentration of reagents, the amount of sample and the flow of reagent rate are optimized by univariate method. With sequential injection sample introducing, the volumes of sample and reagent are reduced greatly and the speed of determination is increased apparently, a throughput of 60 samples/h can be achieved.

[Determination of nitrite in water samples by sequential injection analysis with chemiluminescence detection on chip flow cell].

A sequential injection chemiluminescence's system using a chip flow cell was described for the determination of trace amount of nitrite in water samples. Nitride reacted with hydrogen peroxide to form peroxynitrous acid in sulfuric acid medium, which was an unstable in acid medium and subsequently was quenched into peroxynitrite in basic solution. During the composition of peroxynitrite the chemiluminescence intensity was enhanced with the presence of uranin and ethyldimethylcetylammonium bromide.

[Studies on sequential injection spectrophotometric system using a reflective flow cell for process analysis].

A reflective flow cell was developed and coupled to a sequential injection system and optical fiber photometric detection system based on emitting diode light source. A multistrand bifurcated optical fiber was coupled with incident light, detector and flow cell. Optical fibers were used to carry light from the electronics unit to a reflective flow-through cell and back.

[Nitrogen cycling and its dynamic feature in fine roots of poplar trees and herbs].

The nitrogen cycling and its dynamic feature in fine roots of poplar trees and herbs were studied in Shenyang of Liaoning Province. The results showed that the nitrogen content in the standing biomass of fine roots of poplar trees and herbs was 20.3 kg.