Chlormequat residues and dissipation rates in cotton crops and soil.

A simple and reliable analytical method for chlormequat residues in cotton and soil was established in this study. The residual levels and dissipation rates of chlormequat in cotton crops and soil were determined by High Performance Liquid Chromatography-Mass Spectroscopy (HPLC-MS). The limit of quantification (LOQ) was 0.

Dissipation and residues of chlormequat in wheat and soil.

A specific, sensitive method was developed for the analysis of chlormequat in wheat and soil by high performance chromatography/mass spectrometry. The fortified recoveries of soil were from 75.08% to 96.

Spatial variability of organochlorine pesticides (DDTs and HCHs) in surface soils from the alluvial region of Beijing, China.

The spatial variability in the concentrations of 1,2,3,4,5,6-hexachlorocyclohexane (HCH) and 1,1,1-trichloro-2,2-bis-(p-chlorophenyl) ethane (DDT) in surface soils was studied on the basis of the analysis of 131 soil samples collected from the surface layer (0-20 cm depth) of the alluvial region of Beijing, China. The concentrations of total HCHs (including alpha-, beta-, gamma-, and delta-isomers) and total DDTs (including p,p'-DDT, p,p'-DDD, p,p'-DDE, and o,p'-DDT) in the surface soils tested were in the range from nondetectable to 31.72 microg/kg dry soil, with a mean value of 0.

Health safety of main water pipe materials supplied in China market.

Objective: To assess the health safety of copper, steel and plastic water pipes by field water quality investigations.

Methods: Four consumers were randomly selected for each type of water pipes. Two consumers of every type of the water pipes had used the water pipes for more than 1 year and the other 2 consumers had used the water pipes for less than 3 months.

Expression and characterization of carboxylesterase E4 gene from peach-potato aphid (Myzus persicae) for degradation of carbaryl and malathion.

An abridged carboxylesterase E4 (CbE E4) gene was cloned from the peach-potato aphid, Myzus persicae, by reverse transcription-PCR and subcloned into the expression vector pET28b. The abridged CbE E4 gene was successfully expressed in E. coli BL21 (DE3).

[Study on the resonance scattering light spectra of atrazine-RNA and its analytical application].

The Resonance Light Scattering (RLS) spectra of atrazine with yeast ribonucleic acid (yRNA) had been studied. At pH 1.50, the enhanced RLS of atrazine-yRNA system is characterized by the maximum scattering peaks at 320 nm and the RLS intensity is proportional to the concentration of yRNA.

[Determination of 15 organophosphorus pesticides in cucumber, tomato and pepper samples by capillary gas chromatography with gel permeation chromatographic clean-up].

Fifteen organophosphorus pesticide residues in vegetable samples were extracted and cleaned-up by gel permeation chromatography and detected by capillary GC-FPD. An alternative validation method was established based on GC-NPD detection on an HP-1701 column. The eluting profiles of 15 compounds on a gel permeation column (10 mm i.