Reverse flow-injection analysis

Figure 2.5. Analytical manifolds for the determination of phosphate by flow injection analysis (a) and reverse flow injection (b). The symbols S, M, and A are the seawater, mixed reagent, and the ascorbic acid solutions. The pump injection valve and detector are represented by P, I, and D, respectively. W = waste. From [177]... 

Johnson and Petty [177] adapted reverse flow injection analysis to the well-known Murphy and Riley [178] colorimetric phosphomolybdate reduction method for the determination of phosphate. 

Figure 2.5a and b show flow sheets for the determination of phosphate by flow injection analysis and reversed flow injection analysis, respectively. 

Flow injection analysis is a rapid method of automated chemical analysis that allows for quasi-continuous recording of nutrient concentrations in a flowing stream of seawater. The apparatus used for flow injection analysis is generally less expensive and more rugged than that used in segmented continuous flow analysis. A modified flow injection analysis procedure, called reverse flow injection analysis, was adopted by Thompson et al. [213] and has been adapted for the analysis of dissolved silicate in seawater. The reagent is injected into the sample stream in reverse flow injection analysis, rather than vice versa as in flow injection analysis. This results in an increase in sensitivity. 

Thompson, J. J. and Houk, R. S., Inductively coupled plasma mass spectrometric detection for multielement flow injection analysis and elemental speciation by reversed phase liquid chromatography, Anal. Chem., 58, 2541-2548, 1986. 

J. Toei, Determination of glucose in clinical samples by flow reversal flow injection analysis, Analyst 113 (1988) 475. 

G.D. Clark, J. Zable, J. Ruzicka, G.D. Christian, Flow-reversal flow-injection analysis. Enhancement of flow-injection titrations, Talanta 38 (1991) 119. 

J. Wang and H. D. Dewald, Flow Injection Analysis of Oxidizable Species with Reverse-Pulse Amperometric Detection. Talanta, 29 (1982) 901. 

A. G. Fogg, Reverse Flow Injection Formation of Monitorands in Direct and Indirect On-Line Flow Injection Analysis Methods. Analyst, 111 (1986) 859. 

J. J. Thompson and R. S. Houk, Inductively Coupled Plasma Mass Spec-trometric Detection for Multielement Flow Injection Analysis and Elemental Speciation by Reversed-Phase Liquid Chromatography. Anal. Chem., 58 (1986) 2541. 

Today, no active optode is capable of application in industrial environments for process control. Indeed, the required properties such as reversibility, durability, and reliability are very difHcult to obtain. Nevertheless, various approaches have been made in the laboratory, eg, pH measurements in acidic or basic media [34], the detection of uranium in phosphate medium [166], and the continuous measurement of the concentration of vapors in polar organic solvents using blue thermal paper placed in a flow-through cell [153]. Moreover, the features of the flow-injection analysis (FIA) technique [69, 70] are being adapted in the laboratory to process control. 

See also Arsenic. Flow Injection Analysis Environmental and Agricultural Applications. Membrane Techniques Dialysis and Reverse Osmosis Ultrafiltration Liquid Membranes Pervaporation. Selenium. Sulfur. 

See also Blood and Plasma. Clinical Analysis Overview Sample Handling. Distillation. Extraction Solvent Extraction Principles. Flow Injection Analysis Industrial Applications. Food and Nutritional Analysis Overview. Geochemistry Soil, Major Inorganic Components. Membrane Techniques Dialysis and Reverse Osmosis. Pharmaceutical Analysis Drug Purity Determination. Water Analysis Freshwater Seawater - Inorganic Compounds Industrial Effluents. 

Trujillo, A.J. Isidre, C. Buenaventura, G. Analysis of major ovine milk proteins by reversed-phase high-performance liquid chromatography and flow injection analysis with electrospray ionization mass spectrometry. J. Chromatogr. A, 2000, 870, 371-380. 

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