{"id":5940,"date":"2018-05-21T21:44:49","date_gmt":"2018-05-21T19:44:49","guid":{"rendered":"http:\/\/agora.xtec.cat\/ies-merce-rodoreda\/?p=5940"},"modified":"2018-05-21T21:44:49","modified_gmt":"2018-05-21T19:44:49","slug":"determinacion-de-nitratos-en-las-patatas-por-potenciometria","status":"publish","type":"post","link":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/mediambient\/determinacion-de-nitratos-en-las-patatas-por-potenciometria\/","title":{"rendered":"Determinaci\u00f3n de nitratos en las patatas por Potenciometria"},"content":{"rendered":"<p><a href=\"http:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/patata.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-6117 size-medium aligncenter\" src=\"http:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/patata-300x249.jpg\" alt=\"\" width=\"300\" height=\"249\" srcset=\"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/patata-300x250.jpg 300w, https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/patata-768x637.jpg 768w, https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/patata-1024x850.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>El nitrato est\u00e1 presente de forma natural en el medio ambiente como consecuencia del ciclo del nitr\u00f3geno, que puede ser alterado por diversas actividades agr\u00edcolas e industriales. Entre \u00e9stas cabe destacar la utilizaci\u00f3n de fertilizantes nitrogenados en la agricultura o los vertidos org\u00e1nicos de origen dom\u00e9stico e industrial no sometidos a tratamientos adecuados de depuraci\u00f3n.<\/p>\n<p>El nitrato est\u00e1 ampliamente distribuido en los alimentos, siendo las principales fuentes de exposici\u00f3n los vegetales y el agua de bebida. Algunas especies vegetales tienen gran capacidad de acumulaci\u00f3n de nitrato, por lo que puede ser frecuente encontrar cantidades elevadas en este tipo de productos. El grado de acumulaci\u00f3n no s\u00f3lo depende del tipo y variedad gen\u00e9tica, sino tambi\u00e9n de la temperatura, la luz solar, el nitr\u00f3geno disponible, o el modo de cultivo entre otros factores.<!--more--><\/p>\n<p><strong>Efectos perjudiciales de la ingesta de nitratos<\/strong><br \/>\nUn incremento de metahemoglobina en la sangre, que es una hemoglobina modificada (oxidada) incapaz de fijar el ox\u00edgeno y provoca limitaciones de su transporte en los tejidos. En condiciones normales hay un mecanismo enzim\u00e1tico capaz de restablecer la alteraci\u00f3n y reducir la metahemoglobina otra vez a hemoglobina.<br \/>\nCuando la metahemoglobinemia es elevada, la primera manifestaci\u00f3n cl\u00ednica es la cianosis, generalmente asociada a una tonalidad azulada de la piel.<br \/>\nEn cuanto a la relaci\u00f3n con el c\u00e1ncer, los experimentos realizados parecen indicar que los nitratos no son directamente carcinog\u00e9nicos para los animales y estudios m\u00e1s definitivos no han confirmado la relaci\u00f3n entre\u00a0la ingesta de nitratos y el c\u00e1ncer.<\/p>\n<p><strong>Procedimiento\u00a0<\/strong><\/p>\n<ol>\n<li>La preparaci\u00f3n de la soluci\u00f3n patr\u00f3n de nitratos: se pesa 2,7419g de NaNO3 y lo enrasamos en un erlenmeyer de 1L. (2000ppm)<\/li>\n<li>La preparaci\u00f3n de la soluci\u00f3n sulfato de sodio: en un vaso de precipitado de 250 mL con un volumen de 100 mL le a\u00f1adimos 11,9g de sulfato de sodio y lo mezclamos continuamente, preferiblemente trabajar con un agitador magn\u00e9tico para evitar que se solidifique el sulfato de sodio.<\/li>\n<li>Despu\u00e9s de pelar las patata y picarlas en peque\u00f1o en 3 vasos de precipitado de 250 mL, lo llevamos a la balanza granetaria y pesamos 100g de patata y le a\u00f1adimos 90 mL de agua destilada y 10 mL de sulfato de sodio.\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0<img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-6116 size-medium\" src=\"http:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/muestrasdepatata-300x168.jpg\" alt=\"\" width=\"300\" height=\"168\" srcset=\"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/muestrasdepatata-300x168.jpg 300w, https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/muestrasdepatata-768x430.jpg 768w, https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/muestrasdepatata-1024x573.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/li>\n<li>Procedemos hacer el \u00e1rbol de diluci\u00f3n que partimos de una soluci\u00f3n patr\u00f3n de 2000 ppm y que debe tener 5 patrones finales que va de 7,5-50 ppm y se deben cruzar alg\u00fan patr\u00f3n.<\/li>\n<li>Se le ha de a\u00f1adir 10 mL de sulfato de sodio antes de enrasar el matraz aforado en los 5 patrones finales.<a href=\"http:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/patrones.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-medium wp-image-6118\" src=\"http:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/patrones-300x143.jpg\" alt=\"\" width=\"300\" height=\"143\" srcset=\"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/patrones-300x143.jpg 300w, https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/patrones-768x366.jpg 768w, https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/patrones-1024x488.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/li>\n<\/ol>\n<p><strong>La mediciones con el Potenciometro<\/strong><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-6115 size-medium alignleft\" src=\"http:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/Potenciometro-300x266.jpg\" alt=\"\" width=\"300\" height=\"266\" srcset=\"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/Potenciometro-300x266.jpg 300w, https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/Potenciometro-768x680.jpg 768w, https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2018\/05\/Potenciometro-1024x907.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>Los intervalos de trabajos son m\u00e1s grandes, no influye la turbidez ni el color. Pero su medidas son m\u00e1s inestables y es menos selectivo. En comparaci\u00f3n a la colorimetria.<\/p>\n<p>Cuando se hace las mediciones obtenemos E en Volteos, de los patrones y las muestras,\u00a0 los patrones los tenemos en ppm sean de pasar a molar y luego el logaritmo molar a cada patr\u00f3n y los volteos a minivolteos y con estos datos se obtienen la recta de calibrado.<\/p>\n<p>Y mediante la ecuaci\u00f3n de la recta de calibrado se obtiene la concentraci\u00f3n en ppm de nitratos de cada muestra de patata.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>El nitrato est\u00e1 presente de forma natural en el medio ambiente como consecuencia del ciclo del nitr\u00f3geno, que puede ser [&hellip;]<\/p>\n","protected":false},"author":231,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center 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