Conditions Optimization Cláusulas Exemplificativas
Conditions Optimization. 1. Optimization Criteria
a) Optimization based on stability Good detection stability is the first consideration when doing conditions optimization. And the detection sensitivity can be less considered.
b) Optimization based on sensitivity Detection sensitivity can be the first consideration when doing conditions optimization. However, the detection stability, interferences, and other influence factors also should be considered properly.
Conditions Optimization a) Lamp Current Lamp current is one of the important conditions of static conditions optimization. For normal hollow cathode lamp, excluding some elements, the smaller the lamp current is, the higher the detection sensitivity will be. However, the smaller the lamp current is the worse the detection sensitivity will be. For high performance hollow cathode lamp, the detection sensitivity also will be improved at least dozens of percent when the detection stability is greatly improved, and sometimes even be improved for several times, which is much advantaged to improve the instrument performance. There are already twenty two kinds of HPHCL up to now, especially for hydride elements. Instead of weak and unstable HCL, all the hydride elements use HPHCL to improve the detection stability, and the detection sensitivity are improved several times. So, HPHCL is preferred as far as possible. For HCL, the best current range is between 1mA and 5 mA, and to satisfy the stability requirement, a higher current of 6 mA ~ 7 mA is enough. For HPHCL, the best current range of main current is between 1mA and 5 mA, and the best current range of auxiliary current is between 1mA and 8 mA. Generally, the sum value of the two currents not exceeding 10 mA ~ 12 mA is much better. Another empirical data is that the auxiliary current more or less than the main current with one third would be better. It will be the optimized value when the energy reaching its peak value by adjusting (increasing or decreasing) the auxiliary current.
b) Negative high voltage Negative high voltage is also one of the important conditions of static conditions optimization. The smaller the absolute value of the negative high voltage is, the higher the detection stability will be. The best range of the negative high voltage is between 150 V and 300 V. For much higher value, it’s better not to exceed 400V.
c) Gain Gain selection is peculiar to the static conditions optimization of this instrument. It has a special effect on those unstable and relatively weak element lamps. The negative high voltage can be lower because of the gain selection. A gain selection of two times or four times may be better for the detection stability. However, it is not absolute, and it depends on the specific element. One time gain is usually selected.