Instruments and Techniques
PerkinElmer 2000DV ICP-OES
Norwalk, CT USA
The ICP-OES is the workhorse of the Inductively Coupled Plasma offerings. It is a PerkinElmer 2000DV, optical emission spectrometer.
DV stands for Dual View. The plasma torch is mounted horizontally and a system of mirrors directs the optics to look at the plasma either from below, radial view, or down the length of the plasma, in axial view, which extends the range of the instrument from % and ppm into sub ppm and mid ppb ranges.
In axial view, the tip of the plasma is sheared off by an air knife (N2 in our case), to help define the analytic zone. Not only the sensitivity is magnified by the longer analytical zone, but so is every perturbation, whether caused by inevitable pulsation of the peristaltic pump, differences in sample characteristics, such as viscosity, surface tension etc., so an internal standard is used, and added to each blank, standard and sample at a constant rate via an extra channel on the peristaltic pump.
The instrument calibrates linearly over several orders of magnitude, and is used for the majority of samples coming into this lab for metals analysis. It complements nicely the capabilities of the ICP-MS, where certain elements suffer greatly from interference issues. The ICP-MS is now reserved for truly ultra-trace analyses.
I hope this answers some of your questions regarding ICP-OES. Feel free to visit the lab to have a look at the instruments and I will try to address any questions you might have.