Determination of the Elemental Composition of Ayahuasca and Assessments Concerning Consumer Safety.

The consumption of ayahuasca, a brew prepared from the decoction of two Amazon plants, has increased worldwide in the last decades. This fact raised questions about the safety in its oral administration. In this sense, information concerning the chemical composition of ayahuasca is essential to find a comprehensive reply. Therefore, the aim of this study consisted of determining the elemental composition of ready-to-consume ayahuasca samples produced in Brazil, in order to evaluate the safety in the oral administration of this beverage, considering recommended macroelement and microelement daily intake values and the permitted limits of potentially toxic heavy metals. Real ayahuasca samples, obtained from Brazilian religious groups, underwent microwave radiation-assisted acid decomposition, and Li, Al, Mn, Fe, Co, Cu, Zn, As, Cd, Hg, and Pb concentrations were determined by ICP-MS, while Ca, Mg, K, and P concentrations were determined by ICP OES. Method accuracy was assessed by analyte addition and recovery assays. Recoveries ranged from 80 and 118%, indicating satisfactory accuracy. Limit of detection (LOD) and limit of quantification (LOQ) values were lower than 1 mg L-1 for the macroelements determined by ICP OES and lower than 3.5 µg L-1 for the microelements determined by ICP-MS. The concentrations of the elements determined in the samples were lower than the recommended or tolerable limits; hence, it is possible to affirm that ayahuasca presents safe administration levels regarding total elemental content.

Quantifying proteins at microgram levels integrating gel electrophoresis and smartphone technology.

A combination between gel electrophoresis and smartphone technology is applied for quantifying proteins in a serum sample. Electrophoresis not only allows one to separate different proteins but also to build-up a calibration curve for those proteins. To expand its applicability, a smartphone allows one to capture a gel image, through its camera. Additionally, the treatment of the data extracted through each protein band is performed using a freely available program (PhotoMetrix), which is downloaded to one's own smartphone. Through this approach, the quantification of proteins such as albumin, immunoglobulin, and carbonic anhydrase is performed in a serum sample by acquiring images using 32 × 32 pixels for each image in the region of the protein bands. An LOQ from 1.9 to 2.4 µg and r2 > 0.980 may be obtained. Comparing results through the analyses of the gels using Image Master 2D Platinum 6.0 software reflects good agreement (95% confidence level) between the results. SIGNIFICANCE STATEMENT: In many biological studies involving structural analysis or biophysical and biochemical characterization after purification process, or even in assays of protein:protein interaction, the estimation of protein quantity and protein purity is a fundamental step. However, even although many methodologies are proposed in the literature for quantifying proteins, they present some limitations, once are frequently expensive and require solution sample. In addition, they usually do not quantify the specific active concentration, but the total amount. Thus, it is necessary to develop an easy, fast and low-cost method that allows to quantify and to evaluate protein purity of reactional system, for example, a protein:protein interaction. In this way, we presented a simple strategy based on the integration of Smartphone technology and gel electrophoresis, where SDS-PAGE provides multiple information regarding the quality of the protein, such as the presence of degradation products, as well as if there was interaction reaction between proteins. Then, the smartphone detects the proteins in the SDS-PAGE gel, allowing to evaluate purity degree and the quantity, at microgram level, of the protein. We believe that the combination of these features may help to increase the productivity and accuracy of gel electrophoresis analysis, and the results obtained through a smartphone, easily achieved in our pockets.

Simultaneous determination of free fluoride and monofluorophosphate in toothpaste by capillary electrophoresis with capacitively coupled contactless conductivity detection.

Capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection (C(4)D) was used for rapid, accurate and simultaneous determination of free fluoride and monofluorophosphate (MFP) in six different toothpaste samples. A buffer solution containing 15 mmol L(-1) histine, 25 mmol L(-1) lactic acid, and 2.5 mmol L(-1) tetradecyltrimethylammonium bromide (TTAB) was used as background electrolyte (BGE). A complete separation of the analytes and the internal standard (tartrate) could be attained in less than 2.5 min. The limits of detection (LOD) and quantification (LOQ) were, respectively, 0.17 and 0.57 mg L(-1) for free fluoride and 0.70 and 2.33 mg L(-1) for MFP. Recoveries ranging from 85 to 107% were obtained for samples spiked with standard solutions of free fluoride or MFP. The CE-C(4)D method was compared to an ion-selective electrode (ISE) method and the results were in good agreement. More importantly, the CE-C(4)D method demonstrates the advantage of being able to determine MFP without a prior hydrolysis step.