Spatial variation of PCDD/F and PCB emissions and their composition profiles in stack flue gas from the typical cement plants in China.

Cement production processes are important sources of unintentionally produced persistent organic pollutants (UP-POPs), such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs). The emissions of PCDD/Fs and PCBs in the stack flue gases from eight typical cement plants in China were investigated in this study, including one wet process rotary kiln, three dry process rotary kilns and four vertical shaft kilns. PCBs exhibited relatively higher mass concentrations with the dioxin-like (dl) and indicator PCBs of 0.

A new cleanup method of dioxins in sediment using large volume injection gas chromatography online coupled with liquid chromatography.

A new cleanup method was developed and validated for the determination of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in sediment. The sample extract was first treated with sulfuric acid and then cleaned up by a large volume injection gas chromatography online coupled with liquid chromatography (LVI-GC-LC) system. PCDD/Fs in the extract were separated by a GC column (DB-5), selected cut, cool trapped and transferred to a LC column (alumina).

[Applications of large-volume injection for environmental analysis].

Large-volume injection (LVI) in capillary gas chromatography (CGC) was developed for determining the trace components in environmental samples and for reducing (or even eliminating) the need for cleanup step, also for on-line connection of liquid chromatography (LC) with CGC. The key features of the LVI include sample retained by a large capacity volume liner or a retention gap, and solvent vapor eliminated by solvent vapor exit. There are many kinds of LVI techniques for different analyses, capillary columns and purposes.