A multi-micro-volume pressure-assisted derivatization reaction device has been designed and made for the silylation derivatization of polar heterocyclic aromatic amines by N-(tert-butyldimethylsilyl )-N-methyl-trifluoroacetamide (MTBSTFA) with 1% catalyst tert-butyldimethylchlorosilane (TBDMCS) at a high temperature. The tert-butyldimethylsilyl derivatives then could be automatically analyzed by gas chromatography-mass spectrometry. Using the pressure-assisted device, the silylation reaction may occur at a temperature higher than the boiling points of the reagents, and several micro-volume samples can be simultaneously pretreated in the same device to shorten the sample-preparation time and to improve the repeatability. The derivatization conditions including the headspace volume of the vial, the evaporative surface area of the reagent, derivatization temperature and time have been discussed for the use of the pressure-assisted device. The experimental results proved that the device is an effective way for the simultaneous derivatization of several micro-volume samples at a high temperature. Compared with a common device, the derivative amounts were obviously increased when using the pressure-assisted device at 90 degrees C. Quantitative derivatization can be achieved even at 150 degrees C while there was no common device could be applied at such a high temperature due to the heavy losses of reagents by evaporation. However, no obviously higher reaction speed has been observed in such a circumstance with a higher temperature and a higher pressure using the pressure-assisted device.

In this paper, an electrochemiluminescence (ECL) sensor is fabricated using a covalent bond immobilization approach. A glassy carbon electrode (GCE) modified with gold nanoparticles (AuNPs@GCE) was prepared using a wet chemical method which acts as a support for the ECL reagent. A monolayer of mercaptoacetic acid (MA) was then assembled onto the AuNPs@GCE surface. Finally, an ECL reagent, bis(2,2 0 -bipyridyl) (5-amno-1,10-phen) dichlororuthenium [Ru(bpy) 2 (phen-NH 2 )] 2 2+ , was attached onto the AuNPs@GCE by condensation of the amino group and carboxylic group of MA. Because [Ru(bpy) 2 (phen-NH 2 )] 2 2+ is covalently immobilized on the electrode surface without any polymaterials and directly contacts to the electrolyte, in contrast to traditional ECL sensors fabricated using a polymer technique, mass transportation and electron transfer hindrance is negligible and ECL stability is increased obviously. The sensor is applied in cathodic ECL analysis and presents good performance in a linear range from 1.0 Â 10 À6 mol L À1 to 0.1 mol L À1 and a detection limit of 5 Â 10 À7 mol L À1 for potassium persulfate.