![\"cianosis\"](\"http:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-content\/uploads\/usu644\/2016\/05\/nad\u00f31.jpg\")
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Al laboratori de l\u2019institut vam determinar el contingut de nitrats en les patates i ho vam fer \u00a0mitjan\u00e7ant el m\u00e8tode potenciom\u00e8tric, el qual utilitza un el\u00e8ctrode selectiu, espec\u00edfic per a nitrats, i vam concloure que el seu nivell estava per sota del l\u00edmit perm\u00e8s (Per sort!) Aquest que vam fer servir, \u00e9s un procediment sensible, relativament pr\u00e0ctic i efica\u00e7 per determinar els nivells d\u2019aquest contaminant en l\u2019aigua potable.<\/p>\n <\/p>\n Per\u00f2 com que els nitrats s\u00f3n nocius per a la salut \u00fanicament en concentracions elevades, en moltes circumst\u00e0ncies ens aniria b\u00e9 un m\u00e8tode aproximat. I aqu\u00ed la Qu\u00edmica anal\u00edtica lluny d\u2019un aparell sofisticad\u00edssim i terriblement car ens ha proporcionat una soluci\u00f3 f\u00e0cil i assequible: les tires reactives. Una determinaci\u00f3 semiquantitativa de nitrats que pot ser \u00fatil en moltes circumst\u00e0ncies. A Amazon<\/em> les podem aconseguir per uns 24 \u20ac.<\/p>\n <\/p>\n <\/p>\n Per\u00f2 els reptes no s\u2019acaben, tenim per exemple els PPCP (Personal Care Products) que s\u00f3n productes utilitzats en higiene personal o en cosm\u00e8tica; les EDC (Endocrine Disrupting Chemicals) que son subst\u00e0ncies que a causa de la seva similitud qu\u00edmica amb les hormones alteren el delicat equilibri hormonal en \u00e9ssers vius. Tant els PPCP, les EDC o les mateixes hormones es poden trobar\u00a0 en l\u2019aigua per a consum hum\u00e0 tant sigui en aigua potable de la xarxa p\u00fablica com en aigua embotellada, aix\u00f2 si \u00a0en concentracions \u00ednfimes. Estem davant d\u2019un nou problema de seguretat, perqu\u00e8 no \u00e9s f\u00e0cil ni identificar, ni quantificar aquestes subst\u00e0ncies; ni saber ben b\u00e9 el risc que suposen per a la salut ja que estan en concentracions de nanograms. I per aix\u00f2, a prou feines s\u2019han regulat els seus l\u00edmits en aigua. Un cop m\u00e9s caldr\u00e0 confiar en la Qu\u00edmica Anal\u00edtica, en els seus m\u00e8todes i en els seus aparells per protegir-nos d\u2019aquestes subst\u00e0ncies. De moment la seva resposta s\u00f3n equips que combinen \u00a0dues t\u00e8cniques: la cromatografia i l\u2019espectrometria de masses. Aqu\u00ed sota tenim un d\u2019aquests aparells. El venen a ebay<\/em> per 49.000 d\u00f2lars. Ens el portaran els reis l\u2019any que ve al Rodoreda?<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" M\u00e9s severitat en el control de les aig\u00fces requereix m\u00e9s prestacions tecnol\u00f2giques en els equips de control. Aix\u00ed doncs, que les quantitats considerades com a segures es redueixin comporta inevitablement que els aparells i el m\u00e8todes de detecci\u00f3 hagin de ser cada cop m\u00e9s sensibles. I aquesta \u00e9s sens dubte una de les causes que han fet que la Qu\u00edmica Anal\u00edtica hagi experimentat un desenvolupament dif\u00edcil d\u2019imaginar i, al mateix temps, que una de les grans benefici\u00e0ries hagi estat la seguretat de l\u2019aigua potable dels pa\u00efsos desenvolupats. Desgraciadament, molt queda per fer encara en pa\u00efsos del tercer m\u00f3n.<\/p>\n","protected":false},"author":27,"featured_media":2989,"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":[173],"tags":[284],"class_list":["post-2981","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-modul-a","tag-c4"],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/posts\/2981","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\/27"}],"replies":[{"embeddable":true,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/comments?post=2981"}],"version-history":[{"count":3,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/posts\/2981\/revisions"}],"predecessor-version":[{"id":2998,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/posts\/2981\/revisions\/2998"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/media\/2989"}],"wp:attachment":[{"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/media?parent=2981"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/categories?post=2981"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/agora.xtec.cat\/ies-merce-rodoreda\/wp-json\/wp\/v2\/tags?post=2981"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/a><\/a>