{"id":290,"date":"2017-10-27T13:04:12","date_gmt":"2017-10-27T12:04:12","guid":{"rendered":"http:\/\/wpd.ugr.es\/~fqm302\/blog\/?p=290"},"modified":"2017-10-27T13:04:12","modified_gmt":"2017-10-27T12:04:12","slug":"fully-compatible-and-ultra-sensitive-micellar-electrokinetic-chromatography-tandem-mass-spectrometry-using-sheathless-porous-tip-interfacing","status":"publish","type":"post","link":"https:\/\/wpd.ugr.es\/~fqm302\/blog\/?p=290","title":{"rendered":"Fully compatible and ultra-sensitive micellar electrokinetic chromatography-tandem mass spectrometry using sheathless porous-tip interfacing."},"content":{"rendered":"<p>The on-line coupling of micellar electrokinetic chromatography and mass spectrometry (MEKC-MS) is often hampered by incompatibility problems leading to reduced separation performance and unfavorable limits of detection (LODs). Here we propose a new selective and highly sensitive MEKC-MS\/MS method employing a sheathless porous-tip interface in combination with a micellar phase comprised of semi-volatile surfactant molecules. Carbamate pesticides (CRBs) were selected as representative model compounds being neutral toxic pollutants potentially present at trace levels in environmental water samples. A background electrolyte of 75\u00a0mM perfluorooctanoic acid adjusted to pH 9.0 with ammonium hydroxide allowed efficient separation of 15 CRBs and appeared fully compatible with electrospray ionization (ESI)-MS. Interfacing parameters, such as the distance between the capillary tip and mass-spectrometer inlet, ESI voltage, and dry gas temperature and flow were optimized in order to attain good spray stability and high analyte signal-to-noise ratios. For CRBs the LODs ranged from 0.2 to 3.9\u00a0ng\u00a0L<sup>\u22121<\/sup> (13\u00a0nL injected, i.e., 2% of capillary volume), representing an improvement for certain CRBs of more than 300-fold when compared with conventional sheath-liquid interfacing. Good linearity (R<sup>2<\/sup>\u00a0&gt;\u00a00.99) and satisfactory reproducibility were obtained for all CRBs with interday RSD values for peak area and migration time of 4.0\u201311.3% and below 1.5%, respectively. Analysis of spiked mineral water showed that the new MEKC-MS\/MS method allows selective and quantitative determination of CRB concentrations below the maximum residue limit of 100\u00a0ng\u00a0L<sup>\u22121<\/sup> without the need for sample preconcentration.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The on-line coupling of micellar electrokinetic chromatography and mass spectrometry (MEKC-MS) is often hampered by incompatibility problems leading to reduced separation performance and unfavorable limits of detection (LODs). Here we propose a new selective and highly sensitive MEKC-MS\/MS method employing &hellip; <a href=\"https:\/\/wpd.ugr.es\/~fqm302\/blog\/?p=290\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[74,25,26,62],"tags":[90,101],"class_list":["post-290","post","type-post","status-publish","format-standard","hentry","category-carbamates","category-mekc","category-mass-spectrometry","category-water","tag-ce","tag-ms"],"_links":{"self":[{"href":"https:\/\/wpd.ugr.es\/~fqm302\/blog\/index.php?rest_route=\/wp\/v2\/posts\/290","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wpd.ugr.es\/~fqm302\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpd.ugr.es\/~fqm302\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpd.ugr.es\/~fqm302\/blog\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/wpd.ugr.es\/~fqm302\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=290"}],"version-history":[{"count":1,"href":"https:\/\/wpd.ugr.es\/~fqm302\/blog\/index.php?rest_route=\/wp\/v2\/posts\/290\/revisions"}],"predecessor-version":[{"id":291,"href":"https:\/\/wpd.ugr.es\/~fqm302\/blog\/index.php?rest_route=\/wp\/v2\/posts\/290\/revisions\/291"}],"wp:attachment":[{"href":"https:\/\/wpd.ugr.es\/~fqm302\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=290"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpd.ugr.es\/~fqm302\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=290"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpd.ugr.es\/~fqm302\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=290"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}