Untitled

Funder

Organizational Unit

Publications

Speciation analysis of Arsenic in fish and rice samples using liquid chromatography-inductively coupled plasma mass spectrometry

Publication . Coelho, Inês; Gueifão, Sandra; Castanheira, Isabel

Chemical speciation in foodstuffs is of uttermost importance since it is nowadays recognized that both toxicity and bioavailability of an element depend on the chemical form in which the element is present. Regarding arsenic, inorganic species are classified as carcinogenic while organic arsenic, such as arsenobetaine (AsB) or arsenocholine (AsC), is considered less toxic or even non-toxic. Coupling a High Performance Liquid Chromatographer (HPLC) with an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) combines the power of separation of the first with the selectivity and sensitivity of the second. The present work aims at developing a method, using HPLC-ICP-MS technique, to identify and quantify the chemical species of arsenic present in two food matrices, rice and fish. Two extraction methods, ultrasound and microwave, and different settings were studied. The best method was chosen based on recovery percentages. To ensure that no interconversion of species was occurring, individual spikes of each species of arsenic were made in both matrices and recovery rates were calculated. To guaranty accurate results reference material BCR-627 TUNA FISH, containing certified values for AsB and DMA, was analyzed. Chromatographic separation was achieved using an anion exchange column, HAMILTON-PRP X-100, which allowed to separate the four arsenic species for which standards were available (AsB, dimethylarsenic (DMA), arsenite (AsIII), arsenate (AsV). The mobile phase was chosen based on scientific literature and adjusted to laboratory conditions. Different gradients were studied. As a result we verified that the arsenic species present in both matrices were not the same. While in fish 90% of the arsenic present was in the form of arsenobetaine, in rice 80% of arsenic was present as DMA and 20% as inorganic arsenic.

2012-07Conference object

Unknown

Métodos Analíticos para Caracterização de Contaminantes Inorgânicos e suas Espécies em Alimentos

Publication . Coelho, Inês; Gueifão, Sandra; Castanheira, Isabel; Calhau, Maria Antónia

Objetivos: Neste projeto foi desenvolvida a técnica hifenada de cromatografia liquida acoplada à espectrometria de massa com plasma induzido (HPLC-ICP-MS) que permite determinar os teores de arsénio total e suas espécies químicas, em alimentos. Esta técnica é de extrema importância porque possibilita a identificação de Arsénio Inorgânico (espécies tóxicas) e as espécies de baixa toxicidade . Contributos para as empresas A Food and Drug Administration (FDA) publicou recentemente orientações sobre o teor de arsénio inorgânico em sumos de fruta, arroz e peixe . Assim, é expectável que tanto nos Estados Unidos como em outros seja exigido a apresentação de certificados de análise que evidenciam a conformidade dos produtos, com as recomendações da FDA para das espécies de arsénio pela à técnica hifenada de HPLC-ICP-MS. São apresentados alguns exemplos que, ilustram a necessidade da utilização das técnicas hifenadas bem como, as condições laboratoriais existentes em Portugal, que podem ser postas à disposição das entidades exportadoras.

2015-03-20Other

Restricted access

Bioaccessibility in risk-benefit analysis of raw and cooked seabream consumption

Publication . Afonso, Cláudia; Costa, Sara; Cardoso, Carlos; Coelho, Inês; Castanheira, Isabel; Lourenço, Helena; Gonçalves, Susana; Oliveira, Rui; Carvalho, Maria Luísa; Martins, Maria Fernanda; Bandarra, Narcisa; Nunes, Maria Leonor

The composition of raw and cooked gilthead seabream (Sparus aurata) was analysed. The bioaccessibility of arsenic (As), selenium (Se), mercury (Hg), and methylmercury (MeHg) in raw and cooked fish was studied by an in vitro model. A risk-benefit assessment was performed taking into account bioaccessibility. The content of contaminants Hg and As displayed a significant increase for every culinary treatment, only As content in boiled fish did not increase. Regarding bioaccessibility, while bioaccessible As was high (over 96%), the share of Hg (and MeHg) available for intestinal absorption was reduced by cooking, especially by grilling, 39% (60%) and roasting, 38% (55%). The risk-benefit probabilistic assessment leads to an advice of not exceeding one weekly meal of gilthead seabream. This recommendation concerns mainly pregnant and nursing women. However, Se bioaccessibility was high —minimum of 85% in boiled seabream—, thus helping to balance the deleterious effects of MeHg.

2016-10-17Journal article

Restricted access