Biomedical subjects

Jorge C Masini

Publications and source records attributed to Jorge C Masini.

3 recordsLinked to original sources

PubMed2006

Development of a sequential injection anodic stripping voltammetry (SI-ASV) method for determination of Cd(II), Pb(II) and Cu(II) in wastewater samples from coatings industry.

This paper describes the development and validation of a sequential injection (SI) anodic stripping voltammetry (ASV) method using the hanging mercury drop electrode for accumulation of the heavy metal cations Cu(II), Pb(II) and Cd(II). The method was applied to wastewater samples after proper acid digestion in open vessels to eliminate matrix effects. For a deposition time of 90 s at the flow rate of 10 microl s(-1), the detection limits of the method were 0.06, 0.09 and 0.16 micromol L(-1) for Cd, Pb and Cu, respectively. Under these conditions the linear dynamic range was between 0.20 and 9.0 micromol L(-1) and the sampling frequency was 30 analyses per hour. The relative standard deviation of the method was 3%(n=7) at the concentration level of 2.0 micromol L(-1). The accuracy of the method was evaluated by spiking the samples with known amounts of the metal cations, and by comparison with an independent analytical technique, the inductively coupled plasma atomic emission spectroscopy (ICP-AES). Average recoveries were around of 84%, and the results showed no evidence of systematic errors in comparison to the ICP-AES.

Journal Article↗

PubMed2004

Influence of humic acid on adsorption and desorption of atrazine, hydroxyatrazine, deethylatrazine, and deisopropylatrazine onto a clay-rich soil sample.

Adsorption and desorption properties of atrazine and some of its metabolites, hydroxyatrazine (AT-OH), deethylatrazine (DEA), and deisopropylatrazine (DIA), were studied with a clay-rich soil sample (clay content of 53%). A part of this soil was treated with humic acid (Soil-HA) to assess the influence of this important component of natural organic matter on adsorption and desorption processes. This study was performed using the batch approach with 1.0 g of soil, or Soil-HA, in 5.0 mL of 0.010 mol L(-)(1) CaCl(2) solution containing the herbicide and the metabolites in a concentration range between 0.010 and 5.0 mg L(-)(1). After 24 h of contact time, the suspensions were centrifuged and the four compounds were quantified in the supernatant phases by high-performance liquid chromatography. The adsorption and desorption data of both Soil and Soil-HA were properly fitted by the linearized Freundlich equation. For the untreated soil, the adsorption affinity order evaluated as a function of the K(f) values was AT-OH > AT > DIA > DEA, while desorption followed the order DEA > DIA approximately AT > AT-OH. The presence of humic acid increased significantly the adsorption of all compounds, following the same affinity order observed for the untreated soil. Increase in adsorption was especially high for AT-OH and AT. On the other hand, the dealkylated metabolites, DEA and DIA, were more easily desorbed from the Soil-HA sample, suggesting that natural organic matter facilitates the leaching of these compounds. Desorption order in the presence of humic acid was DEA > DIA > AT > AT-OH.

Adsorption↗

PubMedDate not supplied

Spectrophotometric determination of phenylephrine hydrochloride in pharmaceuticals by flow injection analysis exploiting the reaction with potassium ferricyanide and 4-aminoantipyrine.

This paper presents a method for the determination of phenylephrine hydrochloride in pharmaceuticals by spectrophotometric flow injection analysis exploiting the reaction with potassium ferricyanide and 4-aminoantipyrine, which leads to the formation of a condensation product with strong absorptivity at 500 nm. The linear dynamic range was between 0.95 and 9 mg/L, with a limit of detection of 0.2 mg/L and a sampling throughput of 120 samples per hour. The method was applied to eyewashes and nasal decongestant liquid medicines.

Ampyrone↗