{"id":2958,"date":"2016-05-18T22:42:32","date_gmt":"2016-05-18T21:42:32","guid":{"rendered":"http:\/\/agora.xtec.cat\/ies-merce-rodoreda\/?p=2958"},"modified":"2016-05-18T22:42:32","modified_gmt":"2016-05-18T21:42:32","slug":"espectrofotometre-de-flama","status":"publish","type":"post","link":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/modul-a\/espectrofotometre-de-flama\/","title":{"rendered":"Espectrofot\u00f2metre de flama"},"content":{"rendered":"<p style=\"text-align: center;\"><a href=\"http:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2016\/05\/i_667_16042010161_new.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone  wp-image-2959\" src=\"http:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2016\/05\/i_667_16042010161_new.jpg\" alt=\"i_667_16042010161_new\" width=\"383\" height=\"287\" srcset=\"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2016\/05\/i_667_16042010161_new.jpg 550w, https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2016\/05\/i_667_16042010161_new-300x225.jpg 300w, https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2016\/05\/i_667_16042010161_new-200x150.jpg 200w\" sizes=\"auto, (max-width: 383px) 100vw, 383px\" \/><\/a><\/p>\n<p style=\"text-align: center;\">En aquest apartat us presentar\u00e9 uns dels aparells que m\u00e9s acostumem a utilitzar a la meva empresa on realitzo les pr\u00e0ctiques, aquest s\u2019anomena espectrofot\u00f2metre de flama, la seva marca \u00e9s Corning i el model FP 410. L\u2019equip permet la realitzaci\u00f3 d&#8217;an\u00e0lisi de continguts en sodi, potassi i liti en mostres aquoses i en mostres s\u00f2lides. L&#8217;equip t\u00e9 un l\u00edmit inferior de detecci\u00f3 de 20 ppb de sodi i potassi i la seva sensibilitat de lectura \u00e9s de 100 unitats.<\/p>\n<p><!--more--><\/p>\n<p>L&#8217;espectrosc\u00f2pia d&#8217;emissi\u00f3 amb flama \u00e9s un m\u00e8tode anal\u00edtic basat en la mesura de l&#8217;energia radiant emesa per \u00e0toms (o ions o mol\u00e8cules) d&#8217;un element que es troba en estat de vapor.<\/p>\n<p>A temperatura ambient, tots els \u00e0toms d&#8217;una mostra es troben essencialment en l&#8217;estat fonamental. Els \u00e0toms s\u00f3n elevats a un estat electr\u00f2nic excitat t\u00e8rmicament, \u00e9s a dir, a trav\u00e9s de col\u00b7lisions amb els gasos cremats en la flama. El temps de vida d&#8217;un \u00e0tom en l&#8217;estat excitat \u00e9s breu i la seva volta a l&#8217;estat fonamental va acompanyat de l&#8217;emissi\u00f3 electromagn\u00e8tica i la longitud d&#8217;ona d&#8217;aquesta radiaci\u00f3 est\u00e0 en correspond\u00e8ncia amb la difer\u00e8ncia d&#8217;energia entre tots dos estats. Mitjan\u00e7ant un sistema monocromador o de filtre s&#8217;a\u00eflla la zona de l&#8217;espectre d&#8217;inter\u00e8s i la intensitat del senyal em\u00e8s es mesura amb un sistema fotom\u00e8tric adequat. La correlaci\u00f3 entre la intensitat del senyal i la concentraci\u00f3 de l&#8217;element emissor en una soluci\u00f3 permet la utilitzaci\u00f3 d&#8217;aquest fenomen amb finalitats quantitatives. Si l&#8217;emissi\u00f3 es produeix per la transici\u00f3 des del primer estat excitat al fonamental s&#8217;obtenen les anomenades l\u00ednies de resson\u00e0ncia que s\u00f3n les m\u00e9s intenses i les que s&#8217;utilitzen generalment en aquest m\u00e8tode.<\/p>\n<p>Els processos que condueixen a l&#8217;emissi\u00f3 s&#8217;aconsegueixen mitjan\u00e7ant la introducci\u00f3 de la mostra en el si de la flama. La mostra es nebulitza transformant la dissoluci\u00f3 en un aerosol o \u201cspray\u201d de l\u00edquid que queda susp\u00e8s en el gas que viatja al cremador o encenedor. A causa de la seva simplicitat i sensibilitat la fotometria de flama \u00e9s molt \u00fatil per a certes an\u00e0lisis de rutina, especialment quan s&#8217;analitzen metalls alcalins, alcalinoterris, que s\u00f3n els m\u00e9s f\u00e0cilment excitables i la determinaci\u00f3 dels quals per altres m\u00e8todes \u00e9s en general m\u00e9s complicada. La major dificultat que ofereix aquest m\u00e8tode est\u00e0 originada pel gran nombre de variables que influeixen en la intensitat de la radiaci\u00f3, exigint, per tant, un control acurat de les mateixes per aconseguir una bona reproducibilitat i obligant a l&#8217;ocupaci\u00f3 de solucions patrons de l&#8217;element a determinar. Per aquesta ra\u00f3 no es considera un m\u00e8tode d&#8217;an\u00e0lisi absoluta.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>En aquest apartat us presentar\u00e9 uns dels aparells que m\u00e9s acostumem a utilitzar a la meva empresa on realitzo les [&hellip;]<\/p>\n","protected":false},"author":59,"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 center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[268,173],"tags":[284,285],"class_list":["post-2958","post","type-post","status-publish","format-standard","hentry","category-fct","category-modul-a","tag-c4","tag-tecniques-danalisi"],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/posts\/2958","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/users\/59"}],"replies":[{"embeddable":true,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/comments?post=2958"}],"version-history":[{"count":2,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/posts\/2958\/revisions"}],"predecessor-version":[{"id":2972,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/posts\/2958\/revisions\/2972"}],"wp:attachment":[{"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/media?parent=2958"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/categories?post=2958"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/tags?post=2958"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}