A novel strategy to handle sample and reagent introduction in continuous flow systems is proposed . Basic features such as the effect of flow cell volume, analytical pathlength and peristaltic pump pulsation on the precision of measurement were studied . The manifold was based on a set of three-way
Multicommutation in flow analysis. Part 4. Computer-assisted splitting for spectrophotometric determination of copper and zinc in plants
β Scribed by C.C. Oliveira; R.P. Sartini; B.F. Reis; E.A.G. Zagatto
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 545 KB
- Volume
- 332
- Category
- Article
- ISSN
- 0003-2670
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β¦ Synopsis
An improved splitting process in flow analysis accomplished by means of a computer controlled three-way solenoid valve is proposed. This valve is located at the splitting site, and defines the flow pattern and the portions of the processed sample delivered to each emergent stream. As an application, the simultaneous spectrophotometric determination of copper and zinc in plant digests was selected. The method is based on metal complexation with cyanide, differential kinetics of decomplexation, and reaction with Zincon. The proposed system is very stable and handles 45 samples per hour which corresponds to 0.27 mg Zincon per determination. Precise measurements (r.s.d.=0.7% and 1.7% for first and second peaks) are obtained within 0.00-I .OO mg 1-l Cu and 0.00-2.00 mg I-' Zn. Detection limits are 0.05 and 0.04 mg I-' for Cu and Zn.
Results are in agreement with standard reference materials.
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A method is described for the rapid determination of copper, iron, manganese and zinc on separate aliquots of a single plant digest solution. The coefficients of variation for these elements should not exceed 5% for strawberry, blackcurrant, apple and plum leaves. More variable results may be obtain