New SFA and Discrete Instrumentation

The AA1 nutrient analyser and AQ1 discrete analyser were showcased by Seal Analytical. The AA1 segmented flow analysis (SFA) nutrient analyser consists of an autosampler, a peristaltic pump, a chemistry manifold, a detector and data acquisition software. Sample and reagents are pumped continuously through the chemistry manifold. Air bubbles are introduced at regular intervals forming unique reaction segments which are mixed using glass coils. Glass is ideal, as it is inert, stays clean and enables easy visual checks. In SFA, all reactions run to completion. The ratio of sample to reagents in the detector reaches a constant maximum value - the steady-state condition - for maximum sensitivity resulting in low detection limits and high reproducibility. Instrument control and data acquisition is carried out through the intuitive, easy to use AACE lite software package. The AQ1 discrete analyser employs a robust robotic sampling arm working in conjunction with a stepper motor-driven syringe for aspirating, dispensing and mixing precise quantities of sample and reagent into miniaturised test tubes, or reaction wells. The sample and reagents are incubated in the reaction wells for a pre-programmed time and a single aliquot is then transferred into the stop/flow Optical Quality Glass Cuvette. The absorbance of the reaction is read using a stationary optical bench for best possible signal to noise ratio. The reaction times are user programmable from seconds to minutes. The company has optimised Seal AQ1 Methods to ensure that the chemical reaction is brought to full completion and steady state which emulates both the manual and the segmented flow Methods.