Your most valuable asset is your time.

You desire to use it wisely. If you are reading this you have an interest in chemical analysis, and possibly rapid methods of chemical analysis. The title of this page is "Automated Chemical Analysis". Automation consists of multiple things but in general results from a desire to speed things up so that more analyses can be done per day. Basically, automation is an attempt to gain more time, or at least get better use out of what little we seem to have.

In many instances automation can be simply the use of an auto filling burette, or possibly a titration procedure instead of a gravimetric one. Automation can also include dispensing pipets for repetitive pipeting, pre-weighed filter papers, or use of disposable lab ware. For the most part, however, automation refers to instrumentation that takes the mundane manual tasks away from the lab tech and replaces them with a machine.

How many samples per day is the number one limiting factor that decides what type of automated chemistry analyzer should be used. The next most important, and closely tied, question is the number of tests that will be analyzer per sample. Throughput of a laboratory is limited by the number of tests processed per day. It is, however, very important to be realistic. Many laboratories do not accurately quantify the average number of samples processed per day. Without this knowledge an intelligent decision on what type of analyzer to use cannot be made.

The number of samples per day, number of tests per sample, and variety of matrices and concentration ranges must be known as well as the degree of analyst skill the laboratory is willing to devote to "running the analyzer".

Segmented Flow Analyzers (SFA) are capable of automating almost all wet chemistry tests, of high throughput, high accuracy and precision, with very low detection limits. These significant advantage come with a requirement of a skilled analyst. A multiple channel segmented flow analyzer in the hands of a capable analyst analyzing six methods simultaneously at 90 injections per hour is operating at a throughput of 540 tests per hour. Assuming the laboartory charges $10 per test, this results in $5,400 billable tests per hour of operation. Recall that an autoanalyzer runs unattended meaning that analyst time is minimum and limited to preparing reagents, loading sample cups, and keeping the analyzer operational. Assuming it took a $25 per hour analyst one hour to start the run described the profit realized by the laboratory after deduction of analyst labor and reagent cost is still over $5000 per hour of operation. Segmented Flow Analyzers can also automate dilutions, filtrations, distillations, and digestions further decreasing time and costs leading to the final billable measurement result.

Flow Injection Analyzers (FIA) are simpler forms of SFA and require less operator skill in routine analysis. Flow Injection analyzers are well suited for chemical analysis of a highly repetitive nature - tests the laboratory will do routinely day after day. FIA is an excellent tool for nutrient analysis. FIA methods enjoy essentially the same throughput as SFA making ROI calculations identical to the example given above.

A hidden advantage of FIA is the ease of "changeover" from one method to the next making it slightly easier to analyze multiple tests on a single analyzer without the necessity of simultaneous operation. In the SFA example 6 methods were being analyzed at the same time. A six detector system is difficult to use because it requires the analyst to maintain reagents and chemistry conditions for six methods all at the same time. laboratories rarely have the necessity of 540 tests per hour. A simpler solution is one or two simultaneous tests followed by rapidly changing to the next methods.

Both SFA and FIA instruments limit throughput by the number of active channels. Each channel is capable of one test. Tests are analyzed simultaneously after the sampler picks up the sample and passes it through chemical reactors where reagents are merged into a continuously flowing stream.

Discrete Analyzers are not limited by channels. Chemicals are combined with samples in discrete reaction cuvettes where mixing, incubation, and final color measurement occurs. The limiting factor on a discrete analyzer is the number of incubated reaction chambers instead of the number of channels. Samples per hour throuput on a discrete analyzer is usually determined by the number of reagents per test. Discrete analyzers can perform multiple tests on each sample and only the tests and reagents needed per sample are used. Changeover from one method to the next is automatic. In general, a discrete analyzer requires less operator training than flow methods.