Levels of phenylpropanoids and iridoids in extracts and infusions of Verbena minutiflora.

Herein we report for the first time the levels of phenylpropanoids and iridoids in extracts and infusions of V. minutiflora consumed in Brazil to treat urinary and infectious disorders. An in house validation study demonstrated good accuracy and precision to determine the bioactive compounds in V. minutiflora by HPLC-DAD. Phenylpropanoids varied in the extracts (leaves 139.70 to 221.20 mg g-1, flowers 106.43 to 227.22 mg g-1, stems 42.18 to 56.48 mg g-1). Verbascoside occurred in higher concentration in extracts of leaves (87.66 - 136.16) mg g-1 and flowers (58.12 - 148.96) mg g-1 than in stems (19.24 - 24.62) mg g-1. Iridoids in extracts were as follows: leaves (46.60 - 54.79) mg g-1, flowers (55.88 - 93.87) mg g-1 and stems (40.05 to 61.74) mg g-1. High levels of iridoids (314.70 - 415.10) µg mL-1, phenylpropanoids (1996.39 - 2674.13) µg mL-1 and verbascoside (1029.38 - 1456.42 µg mL-1) in infusions support the popular consume of V. minutiflora.

Fast and direct analysis of Cr, Cd and Pb in brown sugar by GF AAS.

A simple and fast analytical method for the determination of Cr, Pb and Cd in brown sugar by GF AAS using slurry sampling was developed and in house validated for the first time. Analytical curves were prepared by external standardization for Cr, and by matrix simulation for Pb and Cd and they were linear. Low limits of quantification for Cr (32.8 ng g-1), Pb (49.3 ng g-1) and Cd (4.5 ng g-1) were found. Repeatability and intermediate precision estimates (<10% and <15%, respectively) and recovery rates (95-103%) demonstrated a good precision and accuracy. The levels in brown sugar samples ranged from <32.8 to 160 ng g-1 for Cr, from <49.3 to 211.0 ng g-1 for Pb and from <4.5 to 7.0 ng g-1 for Cd and they may be assigned to anthropogenic activities and the adoption of inadequate practices of production and processing.

Direct Determination of Nimesulide in Natural Waters and Wastewater by Cathodic Stripping Voltammetry.

Pharmaceuticals are included in a group of compounds considered as contaminants of emerging concern (CECs) in environmental matrices. The quantification of CECs is typically accomplished using chromatographic methods that require several sample pretreatment steps. The current study proposes a voltammetric method to quantify directly nimesulide (NIM) in aqueous samples. The voltammetric parameters were optimized and chosen based on the profile of the voltammograms and peak current intensity. The adequacy of the analytical method was evaluated using validation criteria, such as accuracy, selectivity, linearity, detection, and quantification limits. Linearity was assessed by a standard addition curve at a concentration range of 0.5-130 µg L-1 of NIM. The limit of quantification was 0.50 µg L-1, with 60 s of preconcentration time. Accuracy was expressed as recovery percentages of NIM and ranged from 111.4 to 119.8%. The voltammetric method herein proposed has several advantages over others already used to determine NIM, such as fewer sample pretreatment steps, faster, and cheaper analyses. NIM was detected in wastewater samples at concentration levels ranging from 101.7 to 385.0 µg L-1. This result is the first evidence about NIM occurrences in environmental matrices in the area surrounding the Itaipu Lake reservoir in Brazil.

Development and in house validation of a new thermogravimetric method for water content analysis in soft brown sugar.

Recently the use of brown sugar has increased due to its nutritional characteristics, thus requiring a more rigid quality control. The development of a method for water content analysis in soft brown sugar is carried out for the first time by TG/DTA with application of different statistical tests. The results of the optimization study suggest that heating rates of 5°C min(-1) and an alumina sample holder improve the efficiency of the drying process. The validation study showed that thermo gravimetry presents good accuracy and precision for water content analysis in soft brown sugar samples. This technique offers advantages over other analytical methods as it does not use toxic and costly reagents or solvents, it does not need any sample preparation, and it allows the identification of the temperature at which water is completely eliminated in relation to other volatile degradation products. This is an important advantage over the official method (loss on drying).