This article presents a set of evaluation guidelines — developed from the author's 20 years of experience demonstrating inductively coupled plasma–optical emission spectrometry (ICP-OES) and ICP–mass spectrometry (MS) instrumentation and running customer samples — to help laboratory scientists make the right decision when selecting an ICP-MS instrument. It focuses on the evaluation process and the most important factors to consider rather than on how to compare the analytical performance of the instruments being evaluated.
So you have read the chapter in my book (1) on comparing inductively coupled plasma–mass spectrometry (ICP-MS) with other atomic spectroscopic techniques and convinced your boss that it is the ideal technique for your laboratory. However, understanding how the instrument works doesn't necessarily give you an insight into how to compare different designs, hardware components, and the difficult-to-define intangible factors such as ease of use, reliability, and technical support; these factors are of critical importance when you have to make a decision regarding which instrument to purchase or what vendor to go with. A number of excellent commercial instruments are available on the market that all look very similar and have very similar specifications, but how do you know which instrument is the best for your application needs or which company will take care of you the best? This article presents some guidelines on how best to evaluate the capability of the instrumentation and to assess the expertise and commitment of the ICP-MS vendor.
Evaluation ObjectivesIt is very important before you begin the selection process to decide what your evaluation objectives are. This is particularly important if you are part of an evaluation committee. It is fine to have more than one objective, but it is essential that all the members of the group begin the evaluation process with the objectives clearly defined. For example, is detection limit performance an important objective for your application, or is it more important to have an instrument that is easy to use? If the instrument is being used on a routine basis, good reliability may be very critical. On the other hand, if the instrument is being used to generate revenue, perhaps sample throughput and cost of analysis are of greater importance. Every laboratory's scenario is unique, so it is important to prioritize before you begin the evaluation process. So, in addition to looking at performance, instrument features, and hardware components, you should make the comparison with your evaluation objectives in mind, based on your particular application needs.
Although price can be considered a valid evaluation guideline, especially if you only have limited funds to purchase an instrument, it will not be discussed in this article. However, you will probably own the instrument for 10 years or more. For that reason, you should purchase the instrument that is best suited for your needs and not the instrument with the lowest price tag. If you are interested in the financial side of the evaluation process, it is presented in greater detail in my book (1). With that in mind, let's take a look at the three most common selection criteria used in the evaluation process.
They typically include
Let's examine these in greater detail.