Pollution status and risk assessment of trace elements in Portuguese water, soils, sediments, and associated biota: a trend analysis from the 80s to 2021.

Pollution of water bodies and sediments/soils by trace elements remains a global threat and a serious environmental hazard to biodiversity and human's health. Globalization and industrialization resulted in the increase and availability of these substances in the environment posing unpredictable adverse effects to living organisms. To determine pollution status and risk contamination by trace elements, data available in the literature of the last 40 years on trace elements occurrence in three environmental matrices (water bodies, sediments/soils, and biota) from Continental Portugal were collected (about 90 studies).

Trace Elements in Ambient Air at Porto Metropolitan Area-Checking for Compliance with New European Union (EU) Air Quality Standards.

Because of the scientific evidence showing that arsenic (As), cadmium (Cd), and nickel (Ni) are human genotoxic carcinogens, the European Union (EU) recently set target values for metal concentration in ambient air (As: 6 ng/m(3), Cd: 5 ng/m(3), Ni: 20 ng/m(3)). The aim of our study was to determine the concentration levels of these trace elements in Porto Metropolitan Area (PMA) in order to assess whether compliance was occurring with these new EU air quality standards. Fine (PM2.

Application of amperometric sol-gel biosensor to flow injection determination of glucose.

A glucose biosensor with enzyme immobilised by sol-gel technology was constructed and evaluated. The glucose biosensor reported is based on encapsulated GOX within a sol-gel glass, prepared with 3-aminopropyltriethoxy silane, 2-(3,4-epoxycyclohexyl)-ethyltrimetoxy silane and HCl. A flow system incorporating the amperometric biosensor constructed was developed for the determination of glucose in the 1x10(-4)-5x10(-3) moll(-1) range with a precision of 1.

Design and development of a multichannel potentiometer for monitoring an electrode array and its application in flow analysis.

A versatile potentiometer that works with electrode arrays in flow injection and/or monosegmented flow systems is described. The potentiometer is controlled by a microcomputer that allows individual, sequential multiplexed or random accesses to eight electrodes while employing only one reference electrode. The instrument was demonstrated by monitoring an array of seven flow-through ion-selective electrodes for Ag+ and for three electrodes for Cl(-), Ca2+ and K+.

Application of lactate amperometric sol-gel biosensor to sequential injection determination of L-lactate.

This work describes the construction and evaluation of lactate sol-gel biosensors to accomplish the determination of lactate in pharmaceutical products. Lactate oxidase was incorporated in a porous sol-gel film placed onto a platinum-based electrode. Acid and basic catalysis were assessed.

Potentiometric behaviour of ion selective electrodes based on iron porphyrins: the influence of porphyrin substituents on the response properties and analytical determination of diclofenac in pharmaceutical formulations.

The potentiometric response characteristics of diclofenac selective electrodes based on Fe(III) tetraphenylporphyrin-chloride (Fe(III)TPP-Cl) and Fe(III) tetrakis(pentafluorophenyl)porphyrin-chloride (Fe(III)TPFPP-Cl) in different mediator solvents and ionic additives are compared. The sensitivity, working range, detection limit, response mechanism, and selectivity of the membrane sensor show a significant dependence on the type of carrier substituent and on the pH value of the sample solution. Studies performed with different amounts of cationic additive (tetra-n-octylammoniumbromide (TOABr)) and anionic additive (sodium tetraphenylborate (NaTPB)) in the membranes allowed the determination of the potentiometric mechanism of action of the used metalloporphyrins.

Construction and evaluation of PVC and sol-gel sensor membranes based on Mn(III)TPP-Cl. Application to valproate determination in pharmaceutical preparations.

The construction and general performance of new valproate-selective electrodes based on manganese(III) tetraphenylporphyrin [Mn(III)TPP-Cl], as an ionophore, are presented. The ionophore was incorporated into PVC and ceramic membranes (sol-gel) based on methyltriethoxysilane. The influence of membrane composition and pH and the effect of lipophilic cationic and anionic additives in PVC membranes were investigated concerning their influence on the slope, response time, selectivity and lifetime of the electrodes.

Ion selective electrodes for penicillin-G based on Mn(III)TPP-Cl and their application in pharmaceutical formulations control by sequential injection analysis.

The work describes the construction, evaluation and analytical application of ion selective electrodes sensitive to penicillin-G antibiotics for pharmaceutical products analysis. Different types of polymeric membranes based on PVC (poly(vinyl chloride)) and EVA (ethyl-vinyl-acetate), without internal reference solution, were prepared using 5,10,15,20-tetraphenylporphyrinate (TPP) manganese(III) (Mn(III)TPP-Cl) as electroactive material. Different additives such as tetra-n-octylammoniumbromide (cationic additive) and sodium tetraphenylborate (anionic additive) were incorporated into the membranes to evaluate their influence on electrodes performance.

Amperometric biosensor based on monoamine oxidase (MAO) immobilized in sol-gel film for benzydamine determination in pharmaceuticals.

The development and application of a flow-through amperometric biosensor for benzydamine determination in anti-inflammatory drugs is described. The biosensor was obtained by physical entrapment of monoamine oxidase in a sol-gel film applied on platinum or carbon paste conducting support. The sol-gel membranes were prepared using an optimum concentration of 3-aminopropyltriethoxy silane, 2-(3,4-epoxycyclohexyl)ethyl-trimethoxy silane, double distilled water saturated with polyethylene glycol 6000 and HCl.

Ion-selective electrodes based on metalloporphyrins for gibberellic acid determination in agricultural products.

This work describes the construction, evaluation and analytical application of electrodes selective to the gibberellate anion for the determination of gibberellic acid in agricultural products. Several types of PVC membrane electrodes without internal reference solution were prepared using the manganese(III) complex of meso-tetraphenylporphyrin (TPP) as ionophore and dibutyl phthalate (DBP), as plasticizer. The incorporation of lipophilic chemical species as additives, was also carried out aiming the evaluation of the response characteristics of the electrodes.