[aeacfm]

simply , which is better spectroscopic methods  of analysis or electrometric methods of analysis ? what i mean is  in general   as the wide spread , easier, simpler, cheaper , accurate , cover all your needs ,.?

[Pradeep]

Most probably that would be spectorscopic methods.

[aeacfm]

but so expensive

[Stepan]

Spectroscopy indeed. It is 5-10 times more expensive, but it is more versatile (many different tests), accuracy approximately 3-5 times better. Sensitivity - depends what you are testing.

[aeacfm]

Sensitivity - depends what you are testing.

.

but at the same time many interferences ( physical , chemical , matrix , spectral ,... may be others ) which need more effort

[Lohe]

It isn't so expensive because you may use a spectrometer during 10-20 years and you don't need very well educated specialist for AA or ICP.

[aeacfm]

the same for electrochemical , we have potetiometry instrument(686 titroprocessor) from about 18 years also i think ICP need well educated operator 

[Stepan]

I would say that electrochemical methods are:
1. limited by number when you compare with capabilities of the spectral methods.
2. more affected by interfering ions than the spectral tests.
3. electrochemical tests just cannot compete with ICP or AA or FTIR. The last 3 give you very different capabilities

Piecewise:
1. Electrochemical: millivoltmeter+ 5 electrodes+ consumables=$1500. Allows you to test 5 parameters (by number of electrodes). Lifespan 2 years of less before you need to replace all electrodes - $800.
2. Spectral: UV VIS+ cuvettes+consumables= $7000. Several hundreds or more different tests for different analytes. Lifespan 10 years before you need to replace a lamp ($300).

this is from my experience.

[aeacfm]

thats exactly what i was looking for , i like numbers
good post buddy