Instant Notes: Analytical Chemistry

600 °C leaving carbon black. The atmosphere is now changed to air, when the carbon black is oxidized away leaving a residue of a ...

Section G – Thermal methods G2 DIFFERENTIAL THERMAL ANALYSIS AND DIFFERENTIAL SCANNING CALORIMETRY Principles If an inert sample ...

melted when the temperatures of the liquid indium and alumina again rise at the same rate. Two alternative strategies can now be ...

The factors that influence the results of thermal methods (see SCRAM in Topic G1) are considered below. ● The sample is generall ...

Calibration of DTA and DSC instruments is usually carried out using stan- dards with well-characterized and tested transition te ...

Many studies of inorganic complexes, of polymer degradations and reactions between samples and reactive gases, have been followe ...

Section G – Thermal methods G3 THERMOMECHANICAL ANALYSIS Principles When any solid sample is heated, it will expand. The coeffic ...

situation to become complex, and the measured modulus, E*,also becomes complex: E*=E’+iE′′ where E’is called the storage modulus ...

Applications The expansion of a plastic component may be studied by TMA.Figure 2shows that below 112°C, the coefficient of expan ...

moisture may lower the temperatures of these transitions and this is easily observed by DMA experiments. As the sample softens t ...

Section G – Thermal methods G4 EVOLVED GAS ANALYSIS Principles During a heating process, any reaction or decomposition may produ ...

which dissociates to give carbon dioxide (m/z44). The third stage produces only carbon dioxide. If several gases are evolved sim ...

break down in several stages over the temperature range 100 to 600°C and the evolution of water, formaldehyde and ammonia and, a ...

Section H – Sensors, automation and computing H1 CHEMICAL SENSORS AND BIOSENSORS Sensors Sensors are small or miniaturized devic ...

binding, methods used including physical adsorption onto or chemical bonding to the surface of the transducer, or entrapment in ...

H1 – Chemical sensors and biosensors 325 Redox electrodesconsisting of crystalline zirconium dioxide, doped with calcium or yttr ...

visible, ultraviolet and near infrared regions by absorbance, fluorescence or reflectance. They have inherent advantages over el ...

H1 – Chemical sensors and biosensors 327 n-Si n-Si pH n-Si n-Si Na+ n-Si n-Si K+ p-Si substrate Fig. 5. FET sensor arrray for mo ...

Section H – Sensors, automation and computing H2 AUTOMATED PROCEDURES Automation The partial or complete automation of analytica ...

tive and repetitive tasks ranging from simple operations, such as weighing samples, adding reagents or filtrations to multistep ...