Methanol In Ultrasonic Bath Research Articles

GC–MS quantitative analysis of black market pharmaceutical products containing anabolic androgenic steroids seized by the Brazilian Federal Police

The use of counterfeit or substandard medicines can have an important health impact, resulting in therapeutic failure, be toxic or even cause death. Anabolic steroids are a frequent target for counterfeiters worldwide, being the second most frequent counterfeited class in Brazil. The aims of this work were to optimize and validate a GC–MS method for the quantitative determination of anabolic steroids in tablet, aqueous suspension and oil solution forms, and to analyze pharmaceutical products sent to Brazilian Federal Police (BFP) for forensic analysis. Sample preparation included extraction with methanol in ultrasonic bath followed by centrifugation. The method was successfully validated and 345 samples of pharmaceutical products were analyzed (328 medicines and 17 dietary supplements). About 42% of the medicines were counterfeits, 28.7% of tablets, 12.0% of suspensions and 65.2% of oil solutions; 11% were considered substandards. Five dietary supplements contained undeclared anabolic steroids, including two containing methandrostenolone at 5.4 and 5.8mg/capsule, equivalent to levels found in medicines. The proposed method is suitable for implementation in routine analysis for identification of counterfeits and substandard products. The analytical results show the need to raise awareness of consumers over the risks from the consumption of anabolic steroids from the clandestine market and for more incisive actions from government agencies aiming at decreasing the availability of these products.

Nanoparticles decorated with a Schiff's base for the microextraction of Cd, Pb, Ni, and Co in environmental samples.

In this paper, we report a new liquid-liquid microextraction procedure called "nanoparticles decorated with a Schiff's base for the microextraction of Cd, Pb, Ni, and Co in environmental samples". The developed procedure was utilized for the extraction of Cd, Pb, Ni, and Co in environmental samples. The Schiff's base was formed by reacting salicylaldehyde with 3-aminopropyltriethoxysilane-functionalized iron oxide nanoparticles. Analyte extraction was conducted in a capillary column system loaded with modified nanoparticles and triton X-114 as dispersion medium. 1-Butyl-3-methylimidazolium hexafluorophosphate was employed as an extraction solvent. Acidified methanol in ultrasonic bath was used as desorption solvent, and elemental determination was carried out with flame atomic absorption spectrometer. Characterization of modified nanoparticles was performed with FTIR spectroscopy and transmission electron microscopy. Solution pH, nanoparticles amount, dispersant concentration, ionic liquid, and temperature were optimized for the extraction. Detection limits obtained for Cd, Pb, Ni, and Co were 0.183, 0.201, 0.241, and 0.192 μgL(-1), respectively, and enhancement factors were 79.1, 86.4, 95.7, and 82.0, respectively. The reproducibility of the developed procedure was in the range of 3.98-5.10%. Validation was checked by applying the developed procedure on certified reference water samples. The microextraction based on nanoparticles decorated with Schiff's base was successfully applied for the extraction of Cd, Pb, Ni, and Co in real environmental water samples.

Stability-Indicating LC Assay for Butenafine Hydrochloride in Creams Using an Experimental Design for Robustness Evaluation and Photodegradation Kinetics Study

A stability-indicating liquid chromatography method for the determination of the antifungal agent butenafine hydrochloride (BTF) in a cream was developed and validated using the Plackett-Burman experimental design for robustness evaluation. Also, the drug photodegradation kinetics was determined. The analytical column was operated with acetonitrile, methanol and a solution of triethylamine 0.3% adjusted to pH 4.0 (6:3:1) at a flow rate of 1 mL/min and detection at 283 nm. BTF extraction from the cream was done with n-butyl alcohol and methanol in ultrasonic bath. The performed degradation conditions were: acid and basic media with HCl 1M and NaOH 1M, respectively, oxidation with H(2)O(2) 10%, and the exposure to UV-C light. No interference in the BTF elution was verified. Linearity was assessed (r(2) = 0.9999) and ANOVA showed non-significative linearity deviation (p > 0.05). Adequate results were obtained for repeatability, intra-day precision, and accuracy. Critical factors were selected to examine the method robustness with the two-level Plackett-Burman experimental design and no significant factors were detected (p > 0.05). The BTF photodegradation kinetics was determined for the standard and for the cream, both in methanolic solution, under UV light at 254 nm. The degradation process can be described by first-order kinetics in both cases.