Multichannel flow injection analysis

J. F. van Staden, Simultaneous Determination of Protein (Nitrogen), Phosphorous and Calcium in Animal Feed Stuffs by Multichannel Flow Injection Analysis. J. Assoc. Anal. Chem., 66 (1983) 718. 

An Expert System for the Supervision of a Multichannel Flow Injection Analysis System... 

The 1950s saw the introduction of a completely new approach to automation, in the form of continuous flow analysis. This made a significant contribution to the advance of automated analysis and subsequent development has been in the form of flow injection analysis. The original instruments were single channel and capable of measuring only one constituent in each sample. Multichannel instruments were then developed which could simultaneously carry out several different measurements on each sample. These were useful in laboratories where many samples required the same range of tests. 

V. Kuban, F. Ingman, Design of a multichannel dropping segmenter for liquid—liquid extraction continuous flow-injection analysis, Anal. Chim. Acta 245 (1991) 251. 

Several instrument manufacturers supply flame photometers designed specifically for the determination of sodium, potassium, lithium, and sometimes calcium in blood serum, urine, and other biological fluids. Single-channel and multichannel (two to four channels) instruments are available for these determinations. In the multichannel instruments, each channel can be used to determine a separate element without an internal standard, or one of the channels can be reserved for an internal standard such as lithium. The ratios of the signals from the other channels to the signal of the lithium channel are then taken to compensate for flame noise and noise from fluctuations in reagent flow rate. Flame photometers such as these have been coupled with flow injection systems to automate the sample-introduction process (see Section 33B-3). Typical precisions for flow-injection-analysis-based flame photometric determinations of lithium, sodium, and potassium in serum are on the order of a few percent or less. Automated flow injection procedures require l/KIO the amount of sample and 1/10 the time of batch procedures. -... 

J C Hoogvliet, J M Reijn, W P van Bennekom, Multichannel amperometnc detection system for liquid chromatography and flow injection analysis. Anal Chem, 63 (1991), 2418-2423... 

FIGURE 1.7 Examples of commercially available flow injection analysis instruments (a) FIAlab2500 analyzer from FIAlab Inc., USA, www.flowinjection.com, (b) FIA2000 multichannel analyzer from Burkard, United Kingdom, www.burkardscientific.co.uk, (c) QuikChem 8500 Series Flow Injection Analyzer from Fachat, USA, www.lachatin-struments.com, and (d) flow injection analysis system from MLE company, Dresden, Germany, www.mle-dresden.com. 

Flow injection analysis is an analytical technique based on injecting a known volume of sample into carrier or reagent streams that are transported in small-diameter conduits (typically 0.5-0.8 mm internal diameter) under laminar flow conditions (Ruzicka and Hansen, 1988 Taljaard and van Staden, 1998 McKelvie, 2008 van Staden and van Staden, 2012 Worsfold et ah, 2013). In this moving stream, the sample does not decompose it is physically and chemically converted into a detectable species that causes a detector response downstream of the injection point (Ruzicka and Hansen, 1988 Taljaard and van Staden, 1998 Saurina, 2008 Saurina, 2010 van Staden and van Staden, 2012). The results will be reproducible on condition that all critical parameters (reproducible injection, controlled reaction time, and controlled dispersion) are held within certain tolerance levels (Ruzicka and Hansen, 1988 Taljaard and van Staden, 1998 van Staden and van Staden, 2012). The basic FIA instrument is composed of a multichannel pump, an injection valve, a flow-through detector, and a signal output device (originally a recorder, lately a computer) (van Staden and van Staden, 2012). Before FIA, relevant variables such as flow rates, reactor dimensions, injection volume(s) and chemical (reaction) conditions... 

Fluidic approaches move samples, reagents, and eluents from place to place entirely through a system of pumps, valves, and tubing. Fluidic methodology from the field of flow injection (FI) analysis has been adapted to the needs of automated radiochemistry. In its original form, FI used a multichannel peristaltic pump and an injection valve in a continuous forward flow paradigm to mix the sample with reagents and... 

Another alternative for designing multi-commuted flow systems operating in the pumping mode is to exploit syringes as fluid propulsion devices. This led to the proposal of multi-syringe flow injection analyser by Albertus et al. in 1999 [109] as an advanced means of managing multichannel flow analysis. 

A schematic of a commercially available system that was conflgured in our laboratory for parallel analysis and purification is shown in Figure 11-9. This four-channel parallel LC/MS purification system consists of a binary HPLC system, an autosampler configured with four injection, a multichannel UV detector, a quadrupole mass spectrometer equipped with an MUX ion source which monitors four flow streams simultaneously, and four independently... 

All mass spectra were obtained on a VG Quattro triple-quadrupole mass spectrometer (Micromass Inc., Altrincham, U.K.). Peptides were ionized with electrospray ionization under the following conditions mobile phase, methanol/water (50/50 v/v) needle voltage, 2.8 kV high voltage lens (counter electrode), 0.05 kV and skimmer potential, -12 V. The flow rate of the mobile phase for the spectra of the whole library was 100 pl/min rather than 10 pl/min, which was used for the samples after binding. All samples were dissolved in methanol. Either 5 or 10 pi of sample was injected. Two injections were performed for each sample. Data were acquired in Multichannel Analysis... 

Fig. 9.7.15 First continuous sampling CE chip designed by Andrew Ewing s group at Pennsylvania State University, (a) Schematic of set-up and principle of operation for continuous flow CE chip used for on-line analysis. Capillary is rastered back and forth laterally at the gap entrance to a chip by linear translation stage actuated by stepper motors, where the analyte is pulled from a continuous flowing stream by EOF and continuously injected onto the chip. A multichannel detector is used to measure the migration of...

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