Determinación de nitratos en vegetales
A number of methods have been devised for the determination of nitrates in plant tissue, but no unanimous agreement has been reached as to which is the most satisfactory. This paper looks at four such methods of plant tissue analysis and seeks to establish correlations among them and set guidelines...
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| Publicado en: | Revista de la Facultad de Ciencias Agrarias |
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| Autores principales: | , , , |
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| Acceso en línea: | https://bdigital.uncu.edu.ar/fichas.php?idobjeto=153 |
| Sumario: | A number of methods have been devised for the determination of nitrates in plant tissue, but no unanimous agreement has been reached as to which is the most satisfactory. This paper looks at four such methods of plant tissue analysis and seeks to establish correlations among them and set guidelines for their selection and applicability. A total of 690 samples for iceberg an butterhead lettuce (Lactuca sativa L. var. capitata) were collected within a one year period at the Mercado Cooperativo de Guaymallén (Mendoza, Argentina). According to the tenors of NO3 - found in the entirety of the studied population, a proportional stratified random sub-sampling was made in order to obtain a number of samples that would represent total population variability.
Four methods were used in the determination of nitrates:
1. the steam distillation method, taken as reference method
2. the colorimetric method, for nitration with salicylic acid
3. the modified colorimetric method.
4. the potentiometric method, with ion selective electrode
Different regression models were used in evaluating the correlation between the reference and the other methods, with the result that being the lineal model the one better suited to all cases. The biggest correlation (r2 = 93 %) existed between the distillation and potentiometric methods. Nevertheless the remaining methods also presented high correlation. Method selection will depend mainly on the number of samples to be analyzed, the required analysis time and the cost.
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