Sub-ppm gas sensor detection via spiral μ-preconcentrator

Development of ultra-low-power consumption MOX sensors with ppb-level VOC detection capabilities for emerging applications

“…[25] using SnO 2 sensors with Au catalyst) and can therefore be considered an exceptional result. In particular, it is worth considering that generally in the literature [26,27] the use of preconcentration systems is assumed to be able to detect similar concentrations.…”

Gas phase micro-preconcentrators for benzene monitoring: A review

“…These devices are available in either packed [11,[18][19][20][21][22] or wall-coated structures [9,[23][24][25][26][27].…”

“…6) [21]. The Pt heater was defined in a pyrex substrate which was anodically sealed to the silicon substrate.…”

The Use of Microchannels for Separation and Preconcentration: Comparison Between Three-Dimensional and Planar Configurations

“…These columns are intended to portable gas chromatograph systems, the development of which in the past four decades led to several innovations, not only in columns, but also in detectors; however, some difficulties still remain, specially regarding the integration of each part to the whole equipment (15,16) . The column is the core of a chromatograph and its miniaturization produced an enormous variety of layouts, but the use of a planar spiral (12,(17)(18)(19) is not uncommon, as explained later, or a serpentine shape (20) . However, three-dimensional microchannels are rarely considered for such equipment and the three-dimensionality concept is usually more referred to high aspect ratio and sudden velocity variations, but reproduced in a flat surface (14,19) , than in production processes based on two or more layers (21) .…”