Best analytical performance

Towards the biosensors with the best analytical performance characteristics... 

The analytical performance of four modes of LC-MS, multiple MS (MS"), and tandem MS operation (APCI and ESI with positive and negative ionizations) has been compared for two mass spectrometers, a triple-quadrupole and an ion-trap instrument.With 15 flavonoids as test compounds, the use of APCI in the negative-ion mode gave the best response, with the signal intensities and the mass-spectral characteristics not differing significantly between the two instruments. Under optimum conditions, full-scan limits of detection of... 

As stated by Manz, the pTAS was envisioned as a new concept for chemical sensing, needed since sensors at that time were not providing the best results in terms of selectivity and lifetime. Initially, the main reason for miniaturisation was to enhance the analytical performance of the device rather than to reduce its size. However, it was also recognised that a small scale presented the advantage of a smaller consumption of sample and reagents. Moreover, the total chemical analysis system scheme could provide an integration of several laboratory procedures such as sample preparation, filtration, preconcentration,... 

It is difficult to conclude what the best analytical method is for PCDEs but, based on the literature, microcolumns such as Florisil [57] seem to be effective in separation of PCDEs from PCDDs and PCDFs. Furthermore they are fast and inexpensive. Before PCDEs can be analyzed by MS, however, an additional cleanup step is needed. This has been performed using column chromatography on carbon, since silica gel and neutral alumina microcolumns have not worked well with fish extracts for this purpose [57]. Activated silica and alumina microcolumns, however, could possibly be alternatives for a carbon column. An activated silica column has been used an additional cleanup step after Florisil and carbon column chromatography in the case of mussel extracts [123]. It is not necessary to separate PCBs from PCDEs, since PCBs have been reported not to interfere in the MS analysis of PCDEs [57,130],... 

The SPME selectivity of fibers coated with polyacrylate, carbowax-DVB or poly-DMS can be improved by working at pH 2 to extract organic acids such as phenols or at pH 12 to extract organic bases such as aromatic amines and aromatic heterocyclic compounds. The following recoveries of each analyte were attained by a polyacrylate fiber (best overall performance) immersed for 30 min in 2 mL of water, at pH 12, containing 10 p,g of... 

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