Evaporator inverse response

An interesting phenomenon is the inverse response which can occur in an evaporator, shown in Fig. 10.13 and already described before. 

However, the gas flow rate must be optimized because it is inversely proportional to droplet size. Larger droplets scatter more light, thereby increasing the analytical signal and sensitivity, but they are also less prone to evaporate, thereby increasing baseline noise. Since the limit of detection is related to the signal-to-noise ratio, the chromatographer must seek the best compromise. Droplet size must be carefully controlled because it establishes the size of the dried solute particles that in turn determines the extent of the linear response. It is important to use the lowest possible evaporative temperature to allow solute crystal formation, to avoid evaporation of solute and destruction of thermo-sensitive solute. 

---