Are there pharmaceutical compounds in sediments or in water? Determination of the distribution coefficient of benzodiazepine drugs in aquatic environment.

Alprazolam, clonazepam and diazepam are drugs belonging to the benzodiazepine class. These drugs might be important environmental contaminants in aquatic media. A total understanding of behavior and fate of drugs in aquatic environment is not available for these and other drugs. Thus, in this work, a complete optimization of sample treatment and extraction of analytes from sediments and water was described, as well a study of sediment/water distribution comparing it with sample characteristics. Ultrasound for 10 min and 3 steps using 3 mL of extraction solvent were chosen as the stirring form for extraction. A methanol/water (1:1) solution pH 12 was the best extraction solvent. Aiming to eliminate interferences, an addition of 10 µL of NaCl 3.06 mol L-1 was necessary after each step of extraction. Sediment and water samples were characterized, presenting different values on physical-chemical parameters. Six distinct sample sets of water and sediments were spiked with each benzodiazepine and analyzed. Kd values varied from 1.4 to 9.2 L kg-1 for clonazepam, 1.8-11.5 L kg-1 for alprazolam and 2.31-12  L kg-1 for diazepam. A principal component analysis showed high dependence on Kd with sample characteristics mainly related to sediments. In the systems, whose sediments presented high levels of clay, silt and organic matter, the drugs presented a great interaction with the solid part of the system, increasing the Kd value. Koc values varied from 149.25 to 634.13 L kg-1 for clonazepam, 186.57-852.48 L kg-1 for alprazolam, and 194.68-1189.81 L kg-1 for diazepam.

In vitro bioaccessibility of Al, Cu, Cd, and Pb following simulated gastro-intestinal digestion and total content of these metals in different Brazilian brands of yerba mate tea.

Yerba mate tea contains various biochemically active substances. However, it can contain toxic metals. Thus, this work reports the total concentrations of Cd, Cu, Pb and Al in the commercial products, as well as the concentrations in infusions prepared. The bioaccessibility of these metals in these infusions was determined for the first time by in vitro digestion. For Al, its bioaccessibility was estimated in the presence of other ingredients used in tea consumption. In addition, the concentrations of phenolic compounds in infusions were also determined. All metals studied were detected in the samples ranging from 76 ng g-1 (Cd) to 526 µg g-1 (Al). In general, Cd and Cu were the most bioaccessible metals, while Al was found in a relatively inert form. The addition of sugar and honey in infusions decreased the Al bioaccessibility. The relationship between the phenolic and the leaching of Al for the beverages was observed.

Ultrasound-assisted emulsification microextraction combined with graphite furnace atomic absorption spectrometry for the chromium speciation in water samples.

A simple method was proposed by ultrasound-assisted emulsification microextraction (UAEME) combined with GF AAS for Cr speciation in water samples using tributhylphosphate (TBP) as extractor solvent and dispersion with ultrasound, without disperser solvent. The selective separation and pre-concentration of Cr(VI) species in an aqueous medium with HCl and NaCl was optimized with Rotatable Central Composite Design. Total Cr was determined after oxidation of Cr(III) to Cr(VI) by KMnO4. This method resulted in detection limits of 0.85 ng L-1 for Cr(VI) and 1.82 ng L-1 for Cr(total), as well as enrichment factors around 77. The accuracy was evaluated with mineral, tap and natural water. The recovery ranged from 90% to 114%. A case study was carried out with Brazilian commercial mineral water and the total concentrations ranged from 0.47 ±â€¯0.01 µg L-1 to 3.9 ±â€¯0.19 µg L-1. The Cr(VI) values ranged from 0.02 ±â€¯0.01 µg L-1 to 2.3 ±â€¯0.13 µg L-1.

Determination of Cu, Cd, Pb and Cr in yogurt by slurry sampling electrothermal atomic absorption spectrometry: A case study for Brazilian yogurt.

A slurry sampling electrothermal atomic absorption spectrometric method is proposed for the determination of trace elements such as Cu, Cr, Cd and Pb in yogurt. The main factors affecting the slurry preparation were optimized: nature and concentration of acid solution and sonication time. The analytical method was validated in-house by calibration, linearity, limits of detection and quantification, precision and accuracy test obtaining satisfactory results in all cases. The proposed method was applied for the determination of Cd, Cr, Cu and Pb in some Brazilian yogurt samples. For these samples, the concentrations ranged from 2.5±0.2 to 12.4±0.2ngg-1; 34±3 to 899±7ngg-1; <8.3 to 12±1ngg-1; and <35.4 to 210±16ngg-1 for Cd, Cu, Cr and Pb, respectively. The daily intake of Cd, Cu, Cr and Pb via consumption of these samples was estimated.

New approach to the determination of contaminants of emerging concern in natural water: study of alprazolam employing adsorptive cathodic stripping voltammetry.

Contaminants of emerging concern (CECs) are chemicals, including pharmaceutical and personal care products, not commonly monitored in the aquatic environment. Pharmaceuticals are nowadays considered as an important environmental contaminant. Chromatography methods which require expensive equipment and complicated sample pretreatment are used for detection of CECs in natural water. Thus, in this study we proposed a simple, fast, and low-cost voltammetric method as a screening tool for the determination of CECs in natural water prior to chromatography. A case study was conducted with alprazolam (benzodiazepine). The method was optimized and validated in-house. The limit of quantification was 0.4 µg L(-1) for a 120 s preconcentration time. The recoveries ranged from 93 to 120 % for accuracy tests. A further proposal aim was to determine for the first time the occurrence of alprazolam in Brazilian river water and to evaluate its potential use as a marker of contamination by wastewater.

Relationship between geographical origin and contents of Pb, Cd, and Cr in honey samples from the state of Paraná (Brazil) with chemometric approach.

The aim of this study was to determine the trace elements, Pb, Cd, and Cr in honey samples from eight different regions from the state of Paraná (Brazil), using slurry sampling graphite furnace atomic absorption spectrometry. Chemometric analysis (principal component analysis (PCA)) was applied to classify honey samples according to their levels of the trace elements Pb, Cd, and Cr, which is also related to the geographical origin of honey samples. The mean concentration for the elements followed the order Pb > Cr > > Cd. The mean values were 200 ± 76, 88 ± 14, and 4.1 ± 4 ng g(-1) for Pb, Cr, and Cd, respectively. It could be verified that honey samples are geographically separated, especially with regard to Pb and Cd contents. Thus, honey can be considered a bioindicator of environmental contamination, suggesting possible contamination in soil, water, and air. This contamination can be related to natural or anthropogenic sources present in the study regions.

Direct determination of Cd, Pb and Cr in honey by slurry sampling electrothermal atomic absorption spectrometry.

Slurry sampling electrothermal atomic absorption spectrometry was used for direct determination of Cr, Pb and Cd in honey without sample pretreatment. The honey slurries were prepared in aqueous solution containing hydrogen peroxide and nitric acid. The slurries were directly introduced in the pyrolytic graphite tubes. Pd-Mg was used as a chemical modifier only for Cd determination. Analytical curves were performed with aqueous standards for Pb and Cr and with addition of fructose for Cd. The quantification limits for Cd, Pb and Cr were 2.0, 5.4 and 9.4ngg(-1), respectively. Acceptable precision of the methodology was obtained through repeatability and intermediate precision. In the accuracy study, recoveries were satisfactory (94-101%) for the three elements. The methodology was applied in honey from Paraná (Brazil). The concentrations of Pb, Cd and Cr ranged from 141 to 228ngg(-1), <2.0 to 8ngg(-1) and 83 to 94ngg(-1), respectively.

Identification of copper sources in urban surface waters using the principal component analysis based on aquatic parameters.

The goal of this work was to identify the sources of copper loads in surface urban waters using principal component analysis under the aquatic parameters data evaluation approach. Water samples from the Irai and Iguacu rivers were collected monthly during a 12-month period at two points located upstream and downstream of a metropolitan region. pH, total alkalinity, dissolved chloride, total suspended solids, dissolved organic matter, total recoverable copper, temperature, and precipitation data provided some reliable information concerning the characteristics and water quality of both rivers. Principal component analysis indicated seasonal and spatial effects on copper concentration and loads in both environments. During the rainy season, non-point sources such as urban run-off are believed to be the major source of copper in both cases. In contrast, during the lower precipitation period, the discharge of raw sewage seems to be the primary source of copper to the Iguacu River, which also exhibited higher total metal concentrations.