Gas chromatographic method for the determination of lumefantrine in antimalarial finished pharmaceutical products

A simple method has been developed and validated for quantitative determination of lumefantrine in antimalarial finished pharmaceutical products using gas chromatography coupled to flame ionization detector. Lumefantrine was silylated with N,O–bis(trimethyl-silyl)trifluoro-acetamide at 70°C for 30 minutes, and chromatographic separation was conducted on a fused silica capillary (HP-5, 30 m length × 0.32 mm i.d., 0.25 μm film thickness) column. Evaluation of the method within analytical quality-by-design principles, including a central composite face-centered design for the sample derivatization process and Plackett–Burman robustness verification of the chromatographic conditions, indicated that the method has acceptable specificity toward excipients and degradants, accuracy [mean recovery = 99.5%, relative standard deviation (RSD) = 1.0%], linearity (=0.9986), precision (intraday = 96.1% of the label claim, RSD = 0.9%; interday = 96.3% label claim, RSD = 0.9%), and high sensitivity with detection limits of 0.01 μg/mL. The developed method was successfully applied to analyze the lumefantrine content of marketed fixed-dose combination antimalarial finished pharmaceutical products

Water reuse in closed hydroponic systems : comparison of GAC adsorption, ion exchange and ozonation processes to treat recycled nutrient solution

In this study, the removal of root exudates from recycled nutrient solution (RNS) in hydroponic systems was investigated by using alternative advanced treatment processes. In particular, the performance of adsorption on granular activated carbon (GAC adsorption), ion exchange (using Amberlite IRA96) and ozonation was evaluated. The characterization of a RNS from a lettuce hydroponic company showed the occurrence of several organic acids including benzoic, maleic, palmitic, stearic, phthalic, succinic, acrylic, adipic, myristic, mannonic, oleic, arachidic and acetic acid. Furthermore, benzoic, acrylic, myristic and palmitic acid were detected even after the RNS treatment by GAC adsorption, ion exchange or ozonation. Further experiments were performed to evaluate the removal efficiency of root exudates from RNS by the selected treatment processes. For this purpose benzoic acid (BA), which is a potent growth inhibitor, was selected as target compound. Benzoic acid occurring at 23 lig/L in the RNS was completely removed by GAC adsorption, ion exchange or ozonation process. In addition, GAC adsorption was the most efficient technique for organic matter removal. Indeed, the COD removal efficiency was 74%, 67% and 22% for GAC adsorption, ozonation and ion exchange treatments, respectively. The results from UV vis absorbance measurements corroborated the best performance of activated carbon in organic compounds removal from RNS. For instance, the absorbance removal at 280 rim reached 82%, 51% and 27% after GAC adsorption, ozonation and ion exchange treatments, respectively

Implementation of HPLC analysis of γ-aminobutyric acid (GABA) in fermented food matrices

In this study, a high-performance liquid chromatography (HPLC) method was adapted to measure the gamma-aminobutyric acid (GABA) and glutamate (Glu) content in different fermented foods. The best solvent to extract GABA and Glu from the food matrices was 75% EtOH and water, combined with 4% SSA as posttreatment. The extracted amino acids were derivatized with o-phthalaldehyde (OPA) for 2 min at room temperature and analyzed by HPLC with fluorescence detector (lambda ex = 340 nm and lambda em = 455 nm). Animal-based fermented products had a higher GABA content, compared with plant-based and soy-based fermented products. Among 17 fermented samples, fish sauce showed the highest amount of GABA (16.29 +/- 0.53 mg/kg DW). Results obtained by the HPLC method were compared with those obtained by a spectrophotometric method, which is based on the reaction of omega-amino acids with phenol. All measured GABA contents, obtained by HPLC method, were much lower than those obtained by the spectrophotometric method, which was due to the nonspecific reaction of the coloring reagent with other amino acids than GABA. It can be concluded that GABA content in food products can only be measured by HPLC

Combining ozone with UV and H2O2 for the degradation of micropollutants from different origins : lab-scale analysis and optimization

The degradation of micropollutants (MPs), including pesticides, herbicides, pharmaceuticals and endocrine disrupting compounds, by ozone-based advanced oxidation techniques (AOP) was investigated in this study. The effect of different factors, such as ozone concentration, hydrogen peroxide concentration and initial pH, on the removal rate was studied in detail. The combination of UV with ozone/ H2O2 increased the MPs degradation. For example, atrazine removal increased from 12.6% to 66.9%. Increasing the concentration of ozone and H2O2 can enhance the degradation efficiency of MPs, while excess H2O2 plays a role as a scavenger for (OH)-O-?. In addition, the optimizing conditions of degradation of MPs by an ozone-based AOP were investigated in this study. The optimal dosages of ozone for atrazine (ATZ), alachlor (ALA), carbamazepine (CBZ), 17-?-ethinylestradiol (EE2) and pentachlorophenol (PCP), were in the range of 0.6?0.75, while for ATZ a much higher dosage (5.4?mg/l) is needed. The optimal dosages of H2O2 concentration were at 0.75, 0.2, 0.47, 0.75 and 0.63?mM, and pH were at 10, 10, 7, 10 and 10, and reaction time at 38.5, 33.5 43, 6 and 6 min, respectively. Ozone-based AOP and in particular combination of UV with ozone and H2O2 is efficient to degrade atrazine, alachlor, carbamazepine, 17-?-ethinylestradiol and pentachlorophenol, and is attractive for future application of real wastewater treatment

N-alkylamide profiling of Achillea ptarmica and Achillea millefolium extracts by liquid and gas chromatography–mass spectrometry

Achillea millefolium and Achillea ptarmica are both plants belonging to the Asteracea family and are traditionally used for their medicinal properties. It has already been shown that some N-alkylamides (NAAs) are responsible for these pharmacological actions. Therefore, in the present study, the NAA content of the two plants was analytically characterised. Different extracts were prepared from the roots, the leaves, the stems and the flowers. The structures of NAAs have been assigned in ethanolic extracts of Achillea millefolium and Achillea ptarmica using high performance liquid chromatography – electrospray ionisation – mass spectrometry (HPLC–ESI–MS) and gas chromatography – electron impact – mass spectrometry (GC–EI–MS). Using both analytical techniques, the structures of 14 and 15 NAAs have been assigned in Achillea ptarmica and Achillea millefolium, respectively. Structures of two new NAAs, previously never observed in Achillea ptarmica, were assigned: deca-2E,6Z,8E-trienoic acid 2-methylbutylamide (homospilanthol) or a related isomeric compound and deca-2E,4E-dienoic acid N-methyl isobutylamide. The structure of homospilanthol or a related isomeric compound was also assigned in Achillea millefolium for the first time

Validation of a simple and robust multi-residue gas chromatography-mass spectrometry method for the analysis of polycyclic aromatic hydrocarbons, phthalates and biocides in roofing material leachate and roof runoff

A multi-residue method for the determination of 16 polycyclic aromatic hydrocarbons (PAHs), biocides diuron (DIU), octylisothiazolinone (OIT) and mecoprop (MCPP), and phthalates bis(2-ethylhexyl) phthalate (DEHP) and diisodecyl phthalate (DIDP) in material leachate and roof runoff is presented. The method aims to keep sample pretreatment as simple as possible, not only to minimize sample contamination and sample losses, but also to have an environmental friendly and cost efficient method with low solvent consumption, in line with the principles of Green Analytical Chemistry. Solid phase extraction (SPE, C18) in combination with GC-MS was used for this purpose. A good separation and accurate detection for the majority of included analytes was obtained, resulting in overall low detection limits ranging between 0.1 ng/L and 18 µg/L in aqueous matrices. Furthermore, the addition of a surrogate standard containing three deuterated PAHs prior to SPE extraction was found to increase the method's repeatability. For the higher molecular weighted PAHs and phthalates, recovery was affected by the concentration level as higher recoveries were observed at lower spiking levels. Furthermore, also the matrix was found to affect the recovery of these higher molecular weighted components as the recoveries in roof runoff and material leachate were higher in comparison to the ones found in bidest water. Water solubility and the affinity to adsorb onto particles were hypothesized to play an important role. The multi-residue SPE-GC-MS method was found to be suitable for the quick and reliable analysis of material leachates and roof runoff samples