Detection Groove

The detection groove is a feature etched into a nticrochannel perpendicular to the fluid flow. The groove is very small, but much deeper than the channel itself, accumulating and mixing the fluid that passes through the channel. This feature can be used to improve the detection sensitivity for shear-driven chromatography. 

The observation that the SDC technique couldn t reach the theoretical predicted efficiency led us to find a way to enhance the detection system. A very simple idea about locally deepened channels was investigated. By creating a small but 10-30 times deeper region (detection groove. Fig. 6a) in the channel structure near the exit, a 10-30 times more intense fluorescent signal can be expected. The groove accumulates the fluid passing in the channel, and instead of... 

The separation experiments with the detection groove were however still insufficient for more qualitative studies. This can be attributed to the semi-manual injection procedure that is not reproducible enough. The standard variation of three consecutive injections can vary from 1 % up to 50 % mainly due to the manual handling in this injection procedure. 

Schematic overview of the detection groove structure. In the nanochannel structure (7-2), a deeper groove (i) is etched to enhance the detection. With this type of groove (with a depth of 4.75 pm see side view), a fivefold decrease in the detection limit could be obtained, (b) Outline of the automated injection system, (a) The supply channels in the PMMA connect to a cavity above the injection micro-well, (b) Wyko (optical profilometry) scan of the backside of the etched well, showing the position of the injection slit in the channel, together with the non-etched channel spacer regions (7, 2) delimiting the lateral extent of the channel and the non-etched region (3) preventing the mobile phase that is present in front of the channel to enter the channel. The flow direction is indicated by the arrows...

McBryant, S.J., E.E. Baird, J.W. Trauger, P.B. Dervan, and J.M. Gotteseeld. Minor groove DNA-protein contacts upstream of a tRNA gene detected with a synthetic DNA binding ligand. /. Mol. Biol. 1999, 286, 973-981. 

A spiral coil of Teflon, or a spiral groove on a stainless steel surface covered with quartz, is used as a flow cell in the CL detector. These cells are placed in front of a photomultiplier tube (PMT), which detects photons emitted by the CL reaction. The cell volumes are generally in the range of 60-120 J.L. 

D.A. Kulesh, R.O. Baker, B.M. Loveless, D. Norwood, S.H. Zwiers, E. Mucker, C. Hartmann, R. Herrera, D. Miller, D. Christensen, L.P. Wasieloski Jr., J. Huggins and P.B. Jahrling, Smallpox and pan-orthopox virus detection by real-time 3 -minor groove binder TaqMan assays on the Roche lightcycler and the Cepheid smart cycler platforms, J. Clin. Microbiol., 42 (2004) 601-609. 

EPR complex. More surface binding into minor groove than intercalation - With complex derivatized by stable nitroxide detection of 3 different + 64... 

The protection of a reactive intermediate complex by the DNA double helix versus a neutral oxidising agent in solution, has also been demonstrated by studying a photo-electron transfer process. In this example the intermediate complex is produced photochemically on the DNA, and is examined spectroscopically after a laser pulsed excitation [73]. Thus Ru(TAP)2(HAT) physically bound to nucleic acid is photo-reduced by hydroquinone during the laser pulse. The intermediate [Ru(TAP)2(HAT)] so-produced, detected by its absorption at 480 nm, is reoxidised by benzoquinone purposely added as oxidant to the solution. It is shown that this reoxidation of the mono-reduced complex is slower in the presence of polynucleotide than in its absence, indicating a protection of the transient mono-reduced complex in the DNA grooves. 

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