Quantification of selenium species in petroleum refinery wastewaters using ion chromatography coupled to post-column isotope dilution analysis ICP-MS

Abstract

A metodologia analítica de diluição isotópica (IDA) pós-coluna foi empregada para realizar ensaios de especiação quantitativa de selênio (Se) em amostras de efluentes industriais através do acoplamento da cromatografia de íons ao ICP-MS, contendo um sistema composto por uma célula de reação (ORS). As interferências ocasionadas pelos dímeros de argônio nos isótopos 78 Se e 80 Se foram suprimidas pressurizando-se a câmara do octapolo com 4 mL min -1 de hidrogênio. Selenito [Se (IV)], selenato [Se (VI)] e selenocianato [SeCN -] foram separados por cromatografia de íons (IC) utilizando eluição isocrática com 20 mmol L -1 Na 2 CO 3 /2 mmol L -1 NaHCO 3 . Após a separação, os íons carbonato presentes no eluente foram convertidos a CO 2 em linha por uma membrana supressora auto-regenerante, a fim de evitar a obstrução do nebulizador ou dos cones de interface do ICP-MS. Limites de detecção (3σ da flutuação da linha de base) de 0,18, 0,13 e 1,0 ng g -1 foram atingidos para Se (IV), Se (VI) e SeCN -, respectivamente. A quantificação do selênio, separadamente em cada espécie, foi executada empregando a análise de diluição isotópica (IDA) pós-coluna, adicionando de modo contínuo uma solução enriquecida com 77 Se ao efluente da coluna supressora. Finalmente, as razões entre os isótopos 78 Se/ 77 Se ou 80 Se/ 77 Se foram monitoradas e a concentração da espécie correspondente de selênio avaliada. A metodologia proposta foi aplicada com sucesso para o estudo de especiação quantitativa do selênio em efluentes de refinarias de petróleo.A post-column Isotope Dilution Analysis (IDA) methodology has been used to carry out the quantitative speciation of selenium (Se) in industrial wastewaters by ion chromatography coupled to ICP-MS with an octapole reaction system (ORS). The interfering argon dimers on the 78 Se and 80 Se isotopes were suppressed by pressurizing the octapole chamber with 4 mL min -1 of hydrogen. The inorganic Se species selenite [Se (IV)], selenate [Se (VI)] and selenocyanate [SeCN -] were separated by ion chromatography (IC) using isocratic elution with 20 mmol L -1 Na 2 CO 3 / 2 mmol L -1 NaHCO 3 as eluent. After the separation, the eluent carbonates were converted to CO 2 on-line by a membrane self-regenerating suppressor, in order to avoid clogging problems in the nebulizer or in the cones of the ICP-MS interface. Detection limits (as 3σ of the baseline noise) of 0.18, 0.13 and 1.0 ng g -1 were achieved for Se (IV), Se (VI) and SeCN -respectively. Quantification of selenium in each separated species was performed using post-column isotope dilution analysis by continuous mixing of an enriched 77 Se spike solution with the effluent from the suppressor column. Finally, the 78 Se/ 77 Se or 80 Se/ 77 Se isotope ratios were monitored and the concentration of the corresponding selenium species was evaluated. The proposed methodology has been successfully applied to study the quantitative speciation of selenium in petroleum refinery wastewaters.

Quantitative Speciation of Selenium in Human Blood Serum and Urine with AE- RP- and AF-HPLC-ICP/MS

“…The good separation of different selenium species is the prerequisite for the purpose of speciation analysis. AE HPLC 15,28 and RP HPLC 29,30 are the popular separation technique for selenium species. In this work, we test the application of the different HPLC modes in selenium separation.…”

Selenium in the Soil-Plant Environment: A Review

“…Fossil fuel is defined as a natural fuel formed in the geological past from the remains of living organisms and includes petroleum, coal and natural gas. Crude oil produced from geological formations containing seleniferous marine shale often contain high levels of selenium which ends up being concentrated into the wastewater during the refining process [58][59][60].…”

Levels of Trace Metals in the Clam, Polymesoda solida (Philippi, 1846) (Bivalvia: Cyrenidae), from the Strait of Lake Maracaibo and Bahía El Tablazo, Venezuela

“…Also, the extraction of petrochemical products is a well-known anthropogenic source of metal contamination, particularly for V, to the LMS as well as to other marine systems (Chiffoleau et al 2004, Alfonso et al 2005, Colina et al 2005, Moradi et al 2011. Petroleum refinery effluents are also known sources of Se (Reyes et al 2009). In addition to urban run-off, other potential sources of metal pollution in LMS include petroleum and chemical industrial activities (Figure 2), spillage from ocean-going ships, and waste discharges from mining activities that are transported into tributaries of LMS (Colina et al 2005, Salazar-Lugo 2009, Ávila et al 2010.…”