Continuous Sampling LC Chips for Process Applications

2 Continuous Sampling LC Chips for Process Applications Characteristics of Ideal LC Microchip Sensors 

In consideration of LC as an on-line sensor, ideal device characteristics would be compactness, speed, very low maintenance, self-containment and low solvent consumption. Compactness is not a given here, albeit the fact that the chips themselves are very small. It is the peripheral system surrounding the chip to which attention needs to be paid in order to minimize footprint. Unlike liquid handling for CE and CEC microchips, hydrodynamic flow components involve pumps and valves, for which more effort is required to miniaturize. We have touched on current advances in these areas already, but extensive development in miniaturization and integration of hydrodynamic fluid handling components is still forthcoming. The following is envisioned. 

Unlike the field of microchip CE, there is almost a total lack of scientific literature covering continuous sampling interfaces for chip-based LC devices. However, the author has investigated sampling methods from continuous sample streams for chip-based LC intended for on-line analysis [52]. We have independently developed a sample flow-through strategy for our LC chips, similar to those described for 

A flow split from the main stream is caused by a smaller line connecting the chip to the sample loop, allowing the split stream, flowing on the order of hundreds of microliters per second to milliliters per 

A pressure head in the line drives an even smaller flow into the microchannel network. The sample flows through a bypass channel (not shown), and plugs are injected at will from this stream. A 10 1 flow reduction is realized in this manner, all the while obtaining a representative sample. 

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