Voltammetry offers a real alternative to atomic absorption spectroscopy, having advaced considerably in the last few years and without the fire risks associated with acetylene
Some hospital biochemistry depts have problems with acetylene because of siting of the lab.
It is can be too high a fire risk to do metal analysis by AAS, so they farm out metals analysis to external contract laboratories.
Rather than just group s 1 and 2 of the Periodic Table, clinicians also want Cu, Zn and Al as key ion for determnation and some hospitals also require the ability to anaylse Hg and Cd to trace levels.
Any labs in a big complex where there could be this fire-risk with atomic absorption spectroscopy (AAS), will potentially have a requirement for Metrohm's voltammetry systems which do not require any gases for the conducting of the analysis Voltammetry has undergone a revolution within the last three years, it now offers the users easy to use software and hardware and lower limits of detection than AAS or ICP, coupled with the added benefit that non-skilled personnel may operate this equipment.
The Metrohm 757VA Computrace offers users trace analysis of heavy metals down to parts per trillion limits of detection.
In addition, the 757VA Computrace analyser offers these sub parts per billion limits of detection at a fraction of the price of AAS or ICP-MS.
The 757 also has very low running costs - using a minimal amount of nitrogen and standard laboratory chemicals, there is no need for expensive lamps, gases or fume extraction facilities.
With over 200 tried and tested applications, the 757 now offers the user cost effective analysis, together with simple to use equipment. The 757 VA Computrace consists of a time tested Metrohm VA stand together with PC controlled Windows 98/2000 software.
Using the software it is possible to analyse whole 'suites' of trace metals together in a single short run, eg, Zn, Cd, Pb, Co, Tl, Ni and Co in waste water according to DIN 38 406.
The 757 is able to offer sub ppb limits of detection by using the technique of stripping voltammetry.
This technique firstly pre-concentrates the contaminants onto the electrode surface, and then once this enrichment step is completed measures the appropriate metal contamination on the electrodes.
The 757 Computrace is eminently suitable for simple routine trace analyses.
All parameters needed for the quantitative evaluation are displayed in an easily surveyed manner within a few windows.
Furthermore, to eliminate matrix interference's the 757 can be connected to a 765 Dosimat to allow automatic standard addition.
The 757 may also be used to identify the different valent states of metals present, eg Cr3+ and Cr6+, while AAS/ICP can only give a total figure. Finally, the 757 can also analyse for these heavy metals in the harshest of environments, eg, highly acidic or saline samples with no effect on the final result.
In fact, the matrix in these cases actually aids the analysis due to their high conductivity, unlike AAS or ICP, where they pose severe limitations.
