Preliminary ionome of the parotoid gland secretion from Rhinella jimi toad.

The cururu toad (Rhinella jimi) is an anuran belonging to the fauna of the Brazilian northeast region, which releases a secretion with toxins from your parotoid glands. Although it has some information about secondary metabolites and proteins, the elemental composition of the released secretion is unknown. Therefore, this is the first report on the ionome of the secretion of the parotoid glands from R. jimi, investigating the influences of abiotic factors such as biome, seasonality, and gender. ICP-MS was used for measurements combined with principal component analysis (PCA). A screening of the secretion sample detected 68 elements which the total concentration of 18 elements was determined. PCA revealed that biome and seasonality factors have a greater influence on the ionomic profile of parotoid secretion. The presence of toxic metals in the secretion samples indicates that the R. jimi toad can be considered a potential bioindicator. These findings may contribute to understanding the metabolism, lifestyle, and interaction of the R. jimi toad with environmental factors as well as open new perspectives to investigate the relationships of the ionome with other biomolecules, for example, metalloproteins and their physiological functions.

Cobalt internal standard for Ni to assist the simultaneous determination of Mo and Ni in plant materials by high-resolution continuum source graphite furnace atomic absorption spectrometry employing direct solid sample analysis.

A new method is proposed for the simultaneous determination of Mo and Ni in plant materials by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS), employing direct solid sample analysis (DSS) and internal standardization (IS). Cobalt was used as internal standard to minimize matrix effects during Ni determinations, enabling the use of aqueous standards for calibration. Correlation coefficients for the calibration curves were typically better than 0.9937. The performance of the method was checked by analysis of six plant certified reference materials, and the results for Mo and Ni were in agreement with the certified values (95% confidence level, t-test). Analysis was made of different types of plant materials used as renewable sources of energy, including sugarcane leaves, banana tree fiber, soybean straw, coffee pods, orange bagasse, peanut hulls, and sugarcane bagasse. The concentrations found for Mo and Ni ranged from 0.08 to 0.63 ng mg(-1) and from 0.41 to 6.92 ng mg(-1), respectively. Precision (RSD) varied from 2.1% to 11% for Mo and from 3.7% to 10% for Ni. Limits of quantification of 0.055 and 0.074 ng were obtained for Mo and Ni, respectively.

Evaluation of alternate lines of Fe for sequential multi-element determination of Cu, Fe, Mn and Zn in soil extracts by high-resolution continuum source flame atomic absorption spectrometry.

The usefulness of the secondary line at 252.744nm and the approach of side pixel registration were evaluated for the development of a method for sequential multi-element determination of Cu, Fe, Mn and Zn in soil extracts by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). The influence of side pixel registration on the sensitivity and linearity was investigated by measuring at wings (248.325, 248.323, 248.321, 248.329, and 248.332nm) of the main line for Fe at 248.327nm. For the secondary line at 252.744nm or side pixel registration at 248.325nm, main lines for Cu (324.754nm), Mn (279.482nm) and Zn (213.875nm), sample flow-rate of 5.0mLmin(-1) and calibration by matrix matching, analytical curves in the 0.2-1.0mgL(-1) Cu, 1.0-20.0mgL(-1) Fe, 0.2-2.0mgL(-1) Mn, 0.1-1.0mgL(-1) Zn ranges were obtained with linear correlations better than 0.998. The proposed method was applied to seven soil samples and two soil reference materials (IAC 277; IAC 280). Results were in agreement at a 95% confidence level (paired t-test) with reference values. Recoveries of analytes added to soil extracts containing 0.15 and 0.30mgL(-1) Cu, 7.0 and 14mgL(-1) Fe, 0.60 and 1.20mgL(-1) Mn, 0.07 and 0.15mgL(-1) Zn, varied within the 94-99, 92-98, 93-101, and 93-103% intervals, respectively. The relative standard deviations (n=12) were 2.7% (Cu), 1.4% (Fe - 252.744nm), 5.7% (Fe - 248.325nm), 3.2% (Mn) and 2.8% (Zn) for an extract containing 0.35mgL(-1) Cu, 14mgL(-1) Fe, 1.1mgL(-1) Mn and 0.12mgL(-1) Zn. Detection limits were 5.4microgL(-1) Cu, 55microgL(-1) Fe (252.744nm), 147microgL(-1) Fe (248.325nm), 3.0microgL(-1) Mn and 4.2microgL(-1) Zn.