Flow-injection analysis apparatus

Flow injection analysis apparatus was successfully used by Watanabe et al. [14] for measuring chlorine dioxide disinfectant residues in water samples. They used 4-aminoantipyrine and phenol reagent (mixture of 0.8 mM 4-aminoantipyrine and 2.0 mM phenol in pH = 9.0 Tris-HCl buffer). 

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. 

The electronic tongue system based on flow injection analysis (FIA) with two amperometric detectors was set up. The FLA apparatus consisted of a Jasco (Tokyo, Japan) model 880 PU pump and two EG G Princeton Applied Research (Princeton, NJ, USA) Model 400 thin-layer electrochemical detector connected in series. Each detector was equipped with a working electrode (a dual glassy carbon electrode and a gold... 

D. Betteridge, W.C. Cheng, E.L. Dagless, P. David, T.B. Goad, D.R. Deans, D.A. Newton, T.B. Pierce, An automated viscometer based on high-precision flow-injection analysis. Part I. Apparatus for high-precision flow-injection analysis, Analyst 108 (1983) 1. 

T. Korenaga, Apparatus for Measuring Chemical Oxygen Demand Based on Flow Injection Analysis [in Japanese]. Bunseki Kagaku, 29 (1980) 222. 

F. A. Shaver and D. J. O Conner, Method and Apparatus for Dosing a Flowing Liquid Stream. Eur. Pat. No. 153530 (Sybron Corp., USA) (1985). J. ROiidka and E. H. Hansen, Flow Injection Analysis [In Chinese. Translated by Fang Zhaolun]. Science Press, Beijing, People s Republic of China (1986). 

Apparatus consisting of a QCM system, which is available commercially (ANT Tech, www.anttech.com.tw) and includes a frequency meter, an oscillator, a port connected to a computer, a software to collect and display on a computer screen, a flow-injected analysis system. 

It is difficult to be automated in its classical form (using a separation funnel or similar apparatus), although a number of flow-system LLE approaches have been presented, applying the principle of flow injection analysis. 

A rotating enzyme-immobilized reactor and a flat pH electrode were incorporated into a sealed cell for use under continuous-flow/stopped-flow (SF) operation for the rapid determination of penicillins G and V in tablets and injectables [50]. A co-immobilization in a rotating bioreactor and amperometric detector resulted in a sensitive system for determination of succinylcholine and acetylcholine in pharmaceutical preparations [51]. A tandem system incorporating two rotating bioreactors into a continuous-flow/SF sample/reagentprocessing setup was apphed for the determination of alkaline phosphatase activity in serum samples [52]. By functional combination of the SF and flow-injection analysis (FIA), an automated micro apparatus was constructed resulting in significant reduction of the injection volumes of enzyme and substrate [53]. SF/continuous flow methods were apphed to acquire kinetic information also [54, 55]. 

In a typical analysis a 10.0-mg sample is dissolved in water and diluted to volume in a 25-mL volumetric flask. A 125- tL aliquot is transferred to a 25-mL volumetric flask and diluted to volume with a pH 9 buffer. When injected into the flow injection apparatus a signal of 21.4 is obtained. What is the %w/w cocaine in the sample ... 

Turbidimetric chloride measurement by FIA turbidimetric method was described by Zagatto and coworkers [47] for the serial analysis of chloride content of natural water samples. A flow injection apparatus was used for the measurements. 

No methods could be found in the literature for the individual flow analysis determination of acesulfame-K. The first flow analysis method for acesulfame-K was proposed by Nikolelis et al. 2001 [72]. This method allowed the electrochemical flow injection monitoring and analysis of mixtures of acesulfame-K, cyclamate, and saccharin using stabilized systems of filter-supported bilayer lipid membranes (BLMs). Detection consisted of t time-dependent appearance of a transient ion current peak in which the time-dependence could be used to distinguish the presence of different artificial sweeteners, and the peak magnitude was related to the concentration of the artificial sweetener. The BLM-based system is able to monitor each artificial sweetener in mixtures. The apparatus for the formation of stabilized BLMs is shown in Figure 24.4. The method also offers response times of less than 1 min, which are the fastest times reported for any similar... 

Carbon monoxide adsorption measurements. To determine the dispersion of the noble metal CO adsorption measurements were performed using a modified Quantasorb apparatus. The samples were reduced in flowing hydrogen for 16 h at 20 °C prior to the analysis. Then, the noble metal dispersion was determined by injection of pulses of CO and measuring the amount of CO which was not adsorbed. A blank experiment showed that Al-N itself did not adsorb any CO. 

The method described by Grob and Zurcher (151 in which a very small amount of charcoal is used to collect volatile compounds has been modified slightly by P. S. Beevor and coworkers, Tropical Products Institute, London (1 61 to collect pheromones from insects. We have adapted and further modified this method. Briefly, it consists of a small charcoal filter prepared by sealing 3-5 mg of charcoal between two 325-mesh stainless steel frits in a 6 mm (0.D.1, 3.7 mm (I.D.l Pyrex tube (Figure 81. This filter is then placed at the exit end of an aeration chamber, and air is drawn through the aeration apparatus at a flow rate of 2.5 liters/min. When aeration is complete, the filter is rinsed with six aliquots (15-20 pi) of distilled dichloromethane the combined aliquots are concentrated to about 5-10 pi by gently warming, and isooctane or another solvent of choice for analysis by capillary GC with splitless injection is added. 

The analyses were performed on a Polymer Lab apparatus, equipped with five ultraStyragel Waters columns (in the order 1000, 500, 10000,100, and 100000 A pore size) attached in series, using a Polymer Lab differential reffactometer. The solvent was THF or CHCI3, the flow rate was 1 mL/min, and 60 microliters of polymeric solution (15 mg/ml) were injected. Normally 50 fractions of 0.2 mL were collected. In the case of sanq)le M30, four different fractionation experiments were performed, and 50 fractions of 0.2 mL, 25 fractions of 0.4 mL, 15 fractions of 0.8 mL, 15 fractions of 1 mL were collected The chromatogram was calibrated using the result of the analysis of MALDI-TOF spectra of selected fractions (see Tables 1 and 2). The average molar masses (Mn and Mw) of the copolymer were measured using the Cahber software distributed by Polymer Lab. The type of calibration selected by us was a narrow standards the calibration function was polynomial of order 1 and the calculation method was area based. ... 

The flow analyzer involves simple apparatus such as samplers, liquid drivers (peristaltic pumps, piston pumps, solenoid pumps), injection devices (rotary valves, injector-commutators), reactors and flow lines (usually narrow bore tubing), mixing chambers, and flow-through detectors. As a rule, these devices are readily available in most laboratories devoted to chemical analysis. Regarding detection, almost all analytical techniques have been used in flow analysis a small flow cell volume and a short response time that is compatible with system dynamics are important detector parameters. 

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