Quartz Technology Ltd
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Quartz Technology Ltd
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For general/ initial studies a balanced array is advantageous, i.e. an array which includes sensors that will show a response to all sample types. The QTS-1 contains just such a balanced array. Sensor 1 This sensor maximises dipolar interactions. The existence of a permanent dipole in the structure of the coating enhances dipole/dipole and dipole/induced dipole interactions. Compounds with a permanent dipole have to align in a certain way to interact with the dipole of the coating and it will improve the chances of their discrimination from other chemical functionalities. Sensor 2 This coating material is moderately dipolar and the sensor is a H-bond acceptor comparable to sensor 7. This sensor interacted with alcohols (H-bond donors) with almost the same magnitude irrespective to their molecular sizes. Sensor 3 This sensor interacts only weakly with hydrophilic molecules (alcohols and amides) but interacted more strongly to hydrophobic dipolar compounds e.g. esters and aromatic compounds through dipole-induced dipole interaction and p-p interactions. Sensor 4 This sensor exhibits strong affinity towards halogenated compounds through dipolar/ polarizability type interactions. The order of interactions was: Cl ñ NO2 ñ C=O, -O- ñ OH ñ Ar ñ CºN ñ R-H. Sensor 5 This material was synthesized for moderate H-bond acid interactions with minimal dispersion effects. The sensor demonstrated just what it was designed for. The fluorocarbon segments in the polymer structure has been proved to be quite inert to dispersion interactions. Sensor 6 This coating material was synthesized for strong H-bond acid interaction. The responses to H-bond acceptors such as amide, amines, ketones and esters are strong . Interactions with alcohols are even stronger through simultaneous H-bond accepting and donating mechanisms. The response to hydrophobic hydrocarbons such as chloroform, hexane and toluene were comparatively low. Sensor 7 This
H-bond base sensor has moderate ability of accepting H-bonds.
This property was demonstrated by its strong response to chloroform which
is chemically slightly acidic due to the inductive effects of the chlorine atoms
in the molecule. The low response
to triehtylamine (a basic molecule) demonstrated that electron donating
molecules were unfavourable adsorbates for the sensor.
Good sensitivity for H-bond donators such as alcohols was observed.
The sensor also demonstrated a low degree of hydrophobic sensitivity such
as to hexane and toluene. Sensor 8 This sensor showed strong affinity for hydrophobic analytes, eg. hexane, and weak interactions to hydrophilic vapours, eg. methanol. The sensor demonstrated good ability to discriminate chemically similar compounds of different chain-lengths and is a typical sensor for dispersive-interactions. |
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