4 documents found, page 1 of 1
A Micro-Extraction Technique Using a New Digitally Controlled Syringe Combined ...
Mendes, Berta; Silva, Pedro; Aveiro, Fernando; Pereira, Jorge; Câmara, José S.The formation of reactive oxygen species (ROS) within cells causes damage to biomolecules, including membrane lipids, DNA, proteins and sugars. An important type of oxidative damage is DNA base hydroxylation which leads to the formation of 8-oxo-7,8-dihydro-29-deoxyguanosine (8-oxodG) and 5-hydroxymethyluracil (5-HMUra). Measurement of these bio markers in urine is challenging, due to the low levels of the anal...
A new and fast methodology to assess oxidative damage in cardiovascular disease...
Mendes, Berta; Silva, Pedro; Mendonça, Isabel; Pereira, Jorge; Câmara, José S.In this work, a new, fast and reliable methodology using a digitally controlled microextraction by packed sorbent (eVol(®)-MEPS) followed by ultra-high pressure liquid chromatography (UHPLC) analysis with photodiodes (PDA) detection, was developed to establish the urinary profile levels of four putative oxidative stress biomarkers (OSBs) in healthy subjects and patients evidencing cardiovascular diseases (CVDs)...
Effect of time and temperature on vitamin C stability in horticultural extracts...
Spínola, Vítor; Mendes, Berta; Câmara, José S.; Castilho, Paula C.Several fruits and vegetables from Madeira Island (Portugal) were evaluated by two analytical methods for their total vitamin C content (l-ascorbic acid, l-AA and dehydroascorbic acid, DHAA). DHAA was determined indirectly with DL-1,4-dithiotreitol (DTT) applied as a pre-column reductant. Ultra high performance liquid chromatography coupled to photodiode array (UHPLC-PDA) determinations were compared with l-AA ...
An improved and fast UHPLC-PDA methodology for determination of L-ascorbic and ...
Spínola, Vítor; Mendes, Berta; Câmara, José S.; Castilho, Paula C.This study provides a versatile validated method to determine the total vitamin C content, as the sum of the contents of L-ascorbic acid (L-AA) and dehydroascorbic acid (DHAA), in several fruits and vegetables and its degradability with storage time. Seven horticultural crops from two different origins were analyzed using an ultra-high-performance liquid chromatographic-photodiode array (UHPLC-PDA) system, equi...