Flow injection procedure

Transposed laboratory methods - This first group is historically the most important as the first developments were carried out in that way. All colorimetric systems using automatic sampling feeding a fast reaction/detection line (for example, with a flow-injection procedure) have been developed from classical procedures, first to increase the analytical rate in laboratories before being transposed for off-line measurement. 

Mohamed et al. reported the use of a flow injection procedure for the analysis of the drug among other antheimentics and antiprotozoal compounds [33], The ethanolic sample solution (24 pL), prepared from tablets or suspensions, was injected into a carrier stream of ethanol and the absorbance measured in an 80 pL flow cell having a path length of 1 cm. The paper reports the analyzing wavelength, flow rate, and other parameters are reported. 

Flow injection procedures are very useful for performing trace analyses in highly concentrated salt solutions. Fang and Welz [270] showed that the flow rate of the carrier solution can be significantly lower than the aspiration rate of the nebulizer. This allows even higher sensitivities than with normal sample delivery can be obtained. Despite the small volumes of sample solution, the precision and the detection limits are practically identical with the values obtained with continuous sample nebulization. The volume, the form of the loop (single loop, knotted reactor, etc.) and the type and length of the transfer line between the flow injection system and the nebulizer considerably influence the precision and detection limits that are attainable. 

Ortega-Barrales, P., Ruiz-Medina, A., Fernandez-De Cordova, M. L., and Molina Diaz, A. Sensitive and simple determination of diclofenac sodium by use of a continuous flow-injection procedure with solid-phase spectroscopic detection. Anal. Sci. 15(10) 985—989, 1999. 

P.J. Worsfold, I.R.C. Whiteside, H.F. Pfeiffer, H. Waldhoff, An automated spectro-photometric flow-injection procedure for the determination of cellulase activity in bioreactor preparations, J. Biotechnol. 14 (1990) 81. 

E.P Borges, B.F. Reis, An enzymatic flow-injection procedure with chemiluminescence detection for on-site determination of L-alanine in synthesis process, J. Braz. Chem. Soc. 16 (2005) 1226. 

A. Sanz, V. Tomas, C. Martinez-Lozano, T. Perez-Ruiz, Extraction-spectrofluorimetric method for the determination of erythromycin and its esters in pharmaceutical formulations using manual and flow-injection procedures, Analyst 118 (1993) 567. 

H. Mana, U. Spohn, Selective flow injection procedures for the determination of nitrogen containing analytes by gas dialytic-fluorimetric detection of enzymatically generated ammonia, Anal. Chim. Acta 325 (1996) 93. 

Tris (2,2 -bipyridyl)ruthenium(II) has been used as the basis of CL detection of a wide range of compounds after oxidation to the ruthenium(III) complex. The analyte interacts with the ruthenium(III) complex reducing it to the ruthenium(II) complex in an excited state, which then emits CL as it returns to the ground state. In the present study, a flow injection procedure for SPAX determination with CL detection was proposed in which ruthenium(II) was oxidized by Ce(IV) solution. The CL emission intensity depended on the concentration of the analyte in the CL system. This work describes a relatively sensitive and rapid chemiluminescence method for SPAX determination based on tris(2,2 -bipyridyl)ruthenium(II) without sample pretreatment process. 

Sulfur Dioxide in Solutions by Pyridinium Bromide Perbromide and Titri-metric and Flow Injection Procedures. Anal. Chim. Acta, 123 (1981) 351. 

A. D. Basson, J. F. van Staden, and P. M. Catttin, Determination of Phosphorous as Molybdovanadophosphoric Acid in Phosphate Rock with a Flow-Injection Procedure. Fresenius Z. Anal. Chem., 307 (1981) 373. 

M. Masoom and P. J. Worsfold, Automated Flow-Injection Procedures for Glycerol and Triglycerides. Anal. Chim. Acta, 188 (1986) 281. 

Sidnei, G. S. Fabio, P.R (2010). A flow injection procedure based on solenoid micropumps for spectrophotometric determination of free glycerol in biodiesel. Talanta. Volume 83, Issue 2,15 December 2010, Pages 559-564. doi 10.1016/j.talanta.2010.09.061. 

The sample is purged within seconds following addition of acid, and is not affected by the presence of chlorinated compounds that hydrolyze slowly in acid solution. A flow injection procedure has recently been developed that makes use of a continuous purge cell. 

Kinetic spectrophotometric methods have also been used. The catalytic effect of manganese(II) on the oxidation of diphenylamine-4-azo-benzen-4 -sul-fonic acid potassium salt with potassium periodate in the presence of 1,10-phenanthroline in weak media has been reported, with an LOD of 0.017ng mH A sensitive flow injection procedure is based on the catalytic effect of manganese on the oxidation of 2-2 -azinobis(3-thylbenzothiazoline-6-sulfonic acid) with periodate (415 nm). 

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. -... 

For the simultaneous determination of PO and SiOg in water, a flow-injection procedure using intermittent flows was proposed. The infermittent flows are attained with a single commutator which permits the implementation of two different methods in the same manifold. With stream intermittence, selectivity is enhanced because of the emphasis on the differences in fhe formation rate of Mo blue. Effects of sample size, flow rate, acidity, etc., were studied. The sample analytical rate is 60 h . Relative standard deviatiorrs were <1% for 2.5-15 mg/L of Si and 0.25-1.5 mg/L of P, detection limit of P was 0.02 xg/L. The resulfs were in good agreemenf wifh fhose of standard methods. 

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