Flow injection analysis natural water samples

Conversely, confluence flow injection systems rely on sample insertion into a chemically inert carrier stream and the required reagents are added by confluence. The configuration is characteristic of the segmented flow analyser. The carrier (or background) stream is a solution similar to the sample but without the chemical species under determination. Distilled water, soil extracting solution, ethanol and synthetic seawater are examples of chemically inert carrier streams for the analysis of natural waters, soil extracts, spirits and seawater, respectively. 

C. Pons, R. Forteza, V. Cerda, The use of anion-exchange disks in an optrode coupled to a multi-syringe flow-injection system for the determination and speciation analysis of iron in natural water samples, Talanta 66 (2005) 210. 

Figure 10.13 Analysis of iodide in a natural water sample. Separator column lonPac AS9-SC eluent 3 mmol/L Na2C03 flow rate 2 mLymin detection UV (227 nm) injection volume 100(iL peaks 268pg/L iodide (1).

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. 

FIGURE 1,6 Example of manifolds developed for flow injection speciation analysis, (a) Manifold of the reversed FIA system for speciation of chromium with pH measurements and spectrophotometric detection, q—peristaltic pumps, V—injection valves, L— reaction coil, M.E.—pH glass electrode. (Adapted from Ruz, J. et al. 1986. J. Autom. Ghent. 8 70-74.) (b) Manifold of branched FIA system for simultaneous biamperomet-ric determination of nitrate and nitrite. (Cd)Cu—reductive column with copperized cadmium, L—mixing coils. (Adapted from Trojanowicz, M., W. Matuszewski, and B. Szostek. 1992. Anal. Chim. Acta 261 391-398.) (c) Example signal recordings obtained in the FIA system shown in (b) 1-6—standard solutions, A-I—natural water samples. Concentration in standard solutions 1—0.075 2—0.050 3—0.025 mM nitrate and 4—7.5 5—5.0 6—2.5 pM nitrite. 

Membrane separation coupled on-line to a flow-injection system was employed for the monitoring of propazine and terbutryn in natural water. A microporous hydro-phobic membrane was utilized in which the analytes were extracted from the aqueous medium into an organic solvent that was carried to the flow cell of a photodiode-array spectrophotometer. The LCDs were 4-5 qg so the technique could potentially be used for screening purposes. Samples with positive detection would require further analysis. 

Laboratory analysis of drinking water may be required to assess possible fluoride excess in natural well waters and may also be necessary during incidents of failure of the equipment used to treat drinking water. The determination of fluoride in urine can be used to assess exposure to different sources of fluoride. For drinking water and urine, direct determination using a fluoride-specific electrode is employed. For food, feces, and tissue, prior separation of fluoride from the sample matrix is required using a Conway diffusion procedure. The combination of the fluoride-electrode with flow injection has allowed a rapid and sensitive method to be used for serum and urine fluoride analysis/ ... 

Benkhedda, K., Infante, H. G., Ivanova, E., and Adams, F. C. (2000) Trace metal analysis of natural waters and biological samples by axial inductively coupled plasma time-of-flight mass spectrometry (ICP-TOFMS) with flow injection on-line adsorption preconcentration using a knotted reactor. J. Anal. At Spectrom., 15,1349. 

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