Direct Determination of Phosphite in Fertilizers by Flow-Injection Amperometry

Abstract In this flow-injection system for direct determination of lithium in serum by atomic absorption spectroscopy, the 10-microL sample is manually injected into a continuously flowing non-segmented stream of de-ionized water, which is pumped, via a dispersion tube, to the spectrometer's nebulizer. Controlled dispersion of the sample zone, before it is introduced into the nebulizer, produces the required sample dilution. Effects of varying the length of the dispersion tube, the flow rate, and the sample size were studied. Analytical readout is obtained, in the form of transient peaks, 5 s after sample injection. It is necessary to include physiological concentrations of sodium and potassium in the standard because each of these cations enhances the lithium absorbance signal. Analytical recovery (98.5 to 101%) and CV (about 2%) are good, and results compare well with those obtained by aspiration of prediluted samples (n = 121, r = 0.99).

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Direct determination of iron in acidified (pH 1.7) seawater samples by flow injection analysis with catalytic spectrophotometric detection: Application and intercomparison

Limnology and Oceanography Methods ◽

10.4319/lom.2006.4.164 ◽

2006 ◽

Vol 4 (6) ◽

pp. 164-171 ◽

Cited By ~ 49

Author(s):

Maeve C. Lohan ◽

Ana M. Aguilar-Islas ◽

Kenneth W. Bruland

Keyword(s):

Flow Injection ◽

Flow Injection Analysis ◽

Direct Determination ◽

Spectrophotometric Detection ◽

Seawater Samples

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Fluorometric Determination of Thiamine Vitamers in Chicken

Journal of AOAC International ◽

10.1093/jaoac/75.2.346 ◽

1992 ◽

Vol 75 (2) ◽

pp. 346-353 ◽

Cited By ~ 4

Author(s):

Jay B Fox ◽

Stanley A Ackerman ◽

Donald W Thayer

Keyword(s):

Flow Injection ◽

Direct Determination ◽

Chromatographic Determination ◽

Nondestructive Method ◽

Phosphate Esters ◽

Light Scatter ◽

Fluorometric Determination ◽

Lower Detection Limit ◽

Lower Detection

Abstract A comparison was made of the direct determination of thiamine In acidified heated chicken extracts, by either flow injection or chromatographic determination, with the standard method (acid and enzyme digestion, adsorption, and elutlon, followed by the fluorometric determination of thiochrome extracted by Isobutanol from K3Fe(CN)6-treated eluates). Liquid chromatography of extracts, followed by oxidation of thiamine vitamers to thlochromes, showed 1 light scatter emission peak and 2 thlochromes, the latter corresponding to thiamine and thiamine monophosphate. Both forms were determined quantitatively by flow Injection determination, the lower detection limit of which was about 60 femtomol. The determination was linear from 0.1 ng to 10 μg thlamlne/mL, and the pooled coefficient of variation was 4%. The determination of thiamine in chicken extracts provides a nondestructive method for determining thiamine and Its phosphate esters, either In toto by flow Injection determination or as individual components by chromatography.

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Chemical Analysis through CL-Detection Assisted by Periodate Oxidation

Bioinorganic Chemistry and Applications ◽

10.1155/2007/92595 ◽

2007 ◽

Vol 2007 ◽

pp. 1-10 ◽

Cited By ~ 7

Author(s):

Nicholaos P. Evmiridis ◽

Athanasios G. Vlessidis ◽

Nicholas C. Thanasoulias

Keyword(s):

Chemical Analysis ◽

Flow Injection ◽

Research Work ◽

Periodate Oxidation ◽

Direct Determination ◽

Good Reproducibility ◽

Through Flow ◽

Set Up ◽

Simple Flow

The progress of the research work of the author and his colleagues on the field of CL-emission generated by pyrogallol oxidation and further application for the direct determination of periodate and indirect or direct determination of other compounds through flow-injection manifold/CL-detection set up is described. The instrumentation used for these studies was a simple flow-injection manifold that provides good reproducibility, coupled to a red sensitive photomultiplier that gives sensitive CL-detection. In addition, recent reports on studies and analytical methods based on CL-emission generated by periodate oxidation by other authors are included.

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