ИСТИНА

In this work, the performance of a new commercially available miniaturised 6-port injection valve for capillary high performance liquid chromatography (HPLC) featuring light weight (ca. 30 g) and small size (18.3 mm in diameter, 64.9 mm height) was evaluated. It can be easily integrated in a miniaturised modular medium pressure capillary LC system based on off-the-shelf components assembled on a breadboard of a commercial flexible microfluidic platform [1]. The internal volume of the injection valve was determined as 98 nL, and injection loops made of standard polyimide coated fused silica were used, giving total injection volume from 178 nL to 1.3 µL. With the spring loaded rotor adjusted to yield maximum operating pressure measured at up to 320 bar (4641 psi), no change of the injection performance at different backpressure values could be observed. The analytical performance parameters of the miniaturised injection valve were demonstrated by chromatographic separation of common cations and biogenic amine on a miniaturised portable LC system, showing an excellent reproducibility of peak areas with < 2% relative standard deviation (RSD).