AutoAnalyzer
Samples and standards are treated in an exactly identical manner as they travel the length of the fluidic pathway, eliminating the necessity of a steady state signal, however, since the presence of bubbles create an almost square wave profile, bringing the system to steady state does not significantly decrease throughput ( third generation CFA analyzers average 90 or more samples per hour) and is desirable in that steady state signals (chemical equilibrium) are more accurate and reproducible.
A continuous segmented flow analyzer (SFA) consists of different modules including a sampler, pump, mixing coils, optional sample treatments (dialysis, distillation, heating, etc.
For typical assays commonly measured with FIA (e.g., nitrite, nitrate, ammonia, phosphate) it is not uncommon to have a throughput of 60-120 samples per hour.
Andres Ferrari reported that analysis was possible without bubbles if flow rates were increased and tubing diameters decreased.
[citation needed] The second generation of the FIA technique, called sequential injection analysis (SIA), was conceived in 1990 by Ruzicka and Marshal, and has been further developed and miniaturized over the course of the following decade.
The enormous volume of FI and SI literature documents the versatility of FI and SI and their usefulness for routine assays (in soil, water, environmental, biochemical and biotechnological assays) has demonstrated their potential to be used as a versatile research tool.
In medical testing applications and industrial samples with high concentrations or interfering material, there is often a dialyzer module in the instrument in which the analyte permeates through a dialysis membrane into a separate flow path going on to further analysis.
In 1974 Ruzicka and Hansen carried out in Denmark and in Brazil initial experiments on a competitive technique, that they termed flow injection analysis (FIA).
[9] Third generation segmented flow analyzers were proposed in the literature,[10] but not developed commercially until Alpkem introduced the RFA 300 in 1984.
The RFA 300 pumps at flow rates less than 1 milliliter per minute through 1 millimeter ID glass mixing coils.
OI Analytical manufactures the only segmented flow analyzer that uses polymeric tubing in place of glass mixing coils.
AutoAnalyzers were used mainly for routine repetitive medical laboratory analyses, but they had been replaced during the last years more and more by discrete working systems which allow lower reagent consumption.
These instruments typically determine levels of albumin, alkaline phosphatase, aspartate transaminase (AST), blood urea nitrogen, bilirubin, calcium, cholesterol, creatinine, glucose, inorganic phosphorus, proteins, and uric acid in blood serum or other bodily samples.
AutoAnalyzers automate repetitive sample analysis steps which would otherwise be done manually by a technician, for such medical tests as the ones mentioned previously.
Over the years the Discrete Sample Analysis method slowly replaced the Continuous Flow system in the clinical laboratory.
[12] The first industrial applications - mainly for water, soil extracts and fertilizer - used the same hardware and techniques as clinical methods, but from the mid-1970s special techniques and modules were developed so that by 1990 it was possible to perform solvent extraction, distillation, on-line filtration and UV digestion in the continuously flowing stream.
In 2005 about two thirds of systems sold worldwide were for water analysis of all kinds,[citation needed] ranging from sub-ppb levels of nutrients in seawater to much higher levels in waste water; other common applications are for soil, plant, tobacco, food, fertilizer and wine analysis.
