Gas Chromatography Coupled With Flame Ionization Detector Research Articles

Assessment of diurnal variation in Ocimum sanctum Linn. by gas chromatographic fingerprint analysis coupled with chemometric methods

Vast intra-specific variations, especially diurnal, geographical and seasonal, have been reported in the chemical composition of essential oils of Ocimum species. The study was conducted to assess diurnal variation in the chemical composition of the leaves of Ocimum sanctum. The leaf samples collected at different times of the day were analyzed by gas chromatography coupled with flame ionization detector (GC-FID). The chromatographic fingerprints of different leaf samples were analyzed by chemometric methods like principal component analysis and hierarchical cluster analysis. No significant difference was found in the chemical compositions of the leaf samples collected at different times of the day. The results lead to a conclusion that O. sanctum does not exhibit diurnal variation in its chemical composition, unlike O. gratissimum.

Modulatory Effects of Alkaloid Extract from Gongronema latifolium (Utazi) and Lasianthera africana (Editan) on Activities of Enzymes Relevant to Neurodegeneration

ABSTRACTMost alkaloids are produced by plants as a defense mechanism against herbivores. Since alkaloids are known to possess pharmacological effects, this study sought to investigate the in vitro modulatory effect of alkaloid obtained from two commonly consumed vegetables in southern Nigeria, Lasianthera africana (editan) and Gongronema latifolium (utazi), on some enzyme activities relevant to neurodegeneration. Effects of the alkaloids on cholinesterases (acetylcholinesterase [AChE] and butyrylcholinesterase [BChE]) and monoamine oxidase (MAO) activities were determined in vitro. In addition, Fe2+ chelating ability as well as radical-scavenging abilities were determined. Alkaloid profile was also determined using gas chromatography coupled with flame ionization detector (GC-FID). The results revealed that the alkaloids inhibited AChE, BChE, and MAO activities in a concentration-dependent manner, such that the alkaloid from G. latifolium showed higher enzyme inhibition (AChE [IC50 = 87.39 µg/ml], BChE [IC50 = 118.65 µg/ml], and MAO [IC50 = 61.37 µg/ml]) than L. africana (AChE = 115.60 µg/ml; BChE = 169.48 µg/ml; MAO = 73.72 µg/ml). In addition, GC-FID analysis revealed abundance of choline in both extracts. Gongronema latifolium and Lasianthera africana alkaloid extracts inhibit enzymes (acetylcholinesterase, butyrylcholinesterase, and monoamine oxidase) implicated in neurodegenerative diseases. Hence, these vegetables could offer dietary supplement in the management of neurodegenerative diseases.

Atmospheric degradation of industrial fluorinated acrylates and methacrylates with Cl atoms at atmospheric pressure and 298 K

The gas-phase reaction of Cl atom with 2,2,2-trifluoroethylacrylate (k1), 1,1,1,3,3,3-hexafluoroisopropylacrylate (k2), 2,2,2-trifluoroethylmethacrylate (k3) and 1,1,1,3,3,3-hexafluoroisopropylmethacrylate (k4), have been investigated at 298 K and 1 atm using the relative method by gas chromatography coupled with flame ionization detection (GC-FID). The values obtained are (in cm3 molecule−1 s−1): k1(Cl+CH2=CHC(O)OCH2CF3) = (2.41 ± 0.57) × 10−10, k2(Cl+CH2=CHC(O)OCH(CF3)2) = (1.39 ± 0.34) × 10−10, k3(Cl+CH2=C(CH3)C(O)OCH2CF3) = (2.22 ± 0.45) × 10−10, and k4(Cl +CH2=C(CH3)C(O)OCH(CF3)2 = (2.44 ± 0.52) × 10−10. Products identification studies were performed by solid-phase microextraction (SPME) method, with on-fiber products derivatization using o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride, coupled with gas chromatography with mass spectrometry detection (GC-MS). Chloroacetone, trifluoroacetaldehyde and formaldehyde were observed as degradation products and a general mechanism is proposed. Additionally, reactivity trends and atmospheric implications are discussed. Significant ozone photochemical potentials (POCP) and acidification potentials lead to local and or regional impact of the esters under study although is expected to a have a minor impact on global warming and climate change.

Determination of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in some personal care products in Nigeria.

The study was carried out to determine the presence and concentration of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in some personal care products in Nigeria. Commonly used consumer care products grouped into four classes, namely: plastics, cosmetics, disinfectants and washing products, were purchased from some supermarkets in Ile-Ife, Nigeria. The solid samples were pulverized and the PAHs and OCPs were extracted with n-hexane and dichloromethane, respectively using Soxhlet extraction method, while the liquid samples were extracted using liquid-liquid extraction method. The quantitative and qualitative determinations were carried out using Gas Chromatography coupled with Flame Ionization Detector (GC-FID) for PAHs, and Gas Chromatography coupled with Electron Capture Detector (GC-ECD) for the OCPs. The results for PAHs analysis gave an overall mean concentration of 3259.10 ± 5223.16 μg g-1 for plastics and 8388.00 ± 7106.55 μg g-1 for cosmetics. Comparatively, the concentrations of PAHs in the cosmetic samples were higher than in plastics samples, while both values were greater than the recommended limits of PAHs in consumer care products as stipulated by the World Health Organization. For the OCPs, disinfectant samples had a total mean concentration of 10.65 ± 6.50 μg mL-1, while washing products had a total mean concentration of 35.31 ± 39.31 μg mL-1. The concentrations of OCPs in washing products were higher than their concentrations in disinfectant samples. The results of the OCPs in some samples were greater than Maximum Residual Limit (MRL) recommended by the European Commission. The study concluded that consumer care products used in this study contained PAHs and OCPs at levels that could be risky to human health if the consumer care products are not used with caution.

Preparation and kinetics study of biodiesel production from waste cooking oil using new functionalized ionic liquids as catalysts

In this work, 1,4-sultone and benzimidazolium-based ionic liquids (ILs) with four different anions were synthesized, and their structures were confirmed by nuclear magnetic resonance (NMR) and elemental analysis (CHNS). The acidity of the synthesized ILs was studied using Hammett acidity function and COSMO-RS. The waste cooking oil was used as a raw material for biodiesel production and their different fatty acids were determined by gas chromatography coupled with flame ionization detector (GC-FID). These four ILs, as catalysts, were screened and comparatively IL 3-methyl-1-(4-sulfo-butyl)-benzimidazolium trifluoromethanesulfonate [BSMBIM][CF3SO3] was selected for further detailed optimization study. This IL experimental efficiency results supported the Hammett acidity function and COSMO-RS study. The catalyst performance was studied and optimised the different parameters. The catalyst efficiency was studied in one and two-step reactions. [BSMBIM][CF3SO3] as a catalyst showed the esterification of waste cooking oil up to 78.13% in a single step reaction. Potassium hydroxide was used in the second step to trans-esterify the waste cooking oil up to 94.52%. The catalyst was reused for seven times with high-yield production. The obtained biodiesel was characterized by GC, NMR, FTIR, thermogravimetric (TGA) and their physicochemical properties were compared with the already established standards. The kinetic study of this transesterification reaction was evaluated and followed the first-order reaction mechanism.

Cellulase-mediated saccharification of lignocellulosic-rich pseudostem of Musa cavendish for bio-ethanol production by Saccharomyces cerevisiae MTCC 4779

ABSTRACTThe present work reports the crude cellulase production using Saccharomyces cerevisiae strain MTCC 4779 and utilization of the crude enzyme in the hydrolysis of Musa cavendish pseudostem. The lignocellulosic-rich pseudostem was enzymatically hydrolyzed to glucose, which was further utilized by S. cerevisiae to produce bio-ethanol, and the distilled product had a concentration of 0.34 g/L. Conclusively, the presence of bio-ethanol was confirmed by qualitative analysis using gas chromatography coupled with flame ionization detection (GC-FID).

Optimization of photocatalytic degradation of biodiesel using TiO2/H2O2 by experimental design

This study reports on the investigation of the photodegradation of biodiesel (B100) in contact with water using TiO2/H2O2. The TiO2 was characterized by X-ray diffraction analysis (XRD), pH point of zero charge (pHpzc) and textural analysis. The results of the experiments were fitted to a quadratic polynomial model developed using response surface methodology (RSM) to optimize the parameters. Using the three factors, three levels, and the Box-Behnken design of experiment technique, 15 sets of experiments were designed considering the effective ranges of the influential parameters. The responses of those parameters were optimized using computational techniques. After 24h of irradiation under an Hg vapor lamp, removal of 22.0% of the oils and greases (OG) and a 33.54% reduction in the total of fatty acid methyl ester (FAME) concentration was observed in the aqueous phase, as determined using gas chromatography coupled with flame ionization detection (GC/FID). The estimate of FAMEs undergo base-catalyzed hydrolysis is at least 3years (1095days) and after photocatalytic treatment using TiO2/H2O2, it was reduced to 33.54% of FAMEs in only 1day.

Distribution Patterns of Polycyclic Aromatic Hydrocarbons in Marshy Soil and Sediments in Warri, Southern Nigeria

This study was carried out to determine the seasonal distribution patterns of Polycyclic Aromatic Hydrocarbons (PAHs) in marshy soil samples in Warri City, Southern Nigeria. The samples were collected during dry and rainy seasons from four locations within Warri and a control location in Agbarho, 20km away. Levels of 16 priority PAHs listed in United States Environmental Protection Agency (USEPA) were determined using Gas Chromatography coupled with Flame Ionization detector (GC-FID). This study was carried from January to March and June to August 2014, representing the dry and wet seasons respectively. Mean levels of individual PAHs for sediment samples in the dry season ranged from 0.001mg/kg low for Acenaphthene to 0.447mg/kg high for Benzo(a)pyrene while for soil samples in the dry season, mean levels ranged from 0.005mg/kg low for Acenaphtylene to 1.069mg/kg high for Benzo(a)pyrene. In the rainy season, individual PAH in sediments ranged from 0.001mg/kg low in acenaphthylene to 0.231mg/kg high for anthracene while for soil samples, mean levels of individual PAHs for rainy season ranged from 0.001mg/kg low in phenanthrene to 0.090mg/kg high for Benzo(b,k)Fluoranthene. Overall, the highest total concentration of individual PAH was recorded for benzo(a)pyrene with 3.302mg/kg in soil samples in the dry season while the lowest total concentration was Acenaphthylene with 0.012mg/kg in sediments in the rainy season. It was observed that PAHs concentration was generally higher in dry than rainy seasons for soil and sediment samples. This can be attributed to dissolution and washing-off of the PAHs during the rainy season.

Thermal Decomposition Kinetics of Polyol Ester Lubricants

Synthetic lubricants are widely used for applications that require high thermal and oxidative stability. In order to facilitate new designs and applications for these fluids, we are measuring a suite of thermophysical and transport properties for lubricant base fluids and mixtures. As part of the property measurements, here, we report the global thermal decomposition kinetics of four polyol ester lubricant base oils, in addition to a fully qualified (MIL-PRF-23699) formulation. The fluids were heated in stainless steel ampule reactors and the extent of decomposition was measured by gas chromatography coupled with flame ionization detection (GC-FID), from which pseudo-first-order rate constants were derived. The rate constants for decomposition ranged from 1 × 10–8 s–1 at 500 K to 2 × 10–4 s–1 at 675 K. Arrhenius parameters across this temperature regime are also reported. Other techniques for chemical characterization applied in this work include gas chromatography with mass spectrometry (GC-MS), nuclear ...

English

A comparative analysis between crude and purified extracts obtained from withered leaves of Terminalia catappa (T. catappa) and pure compounds of anthocyanidins as organic sensitizers in solar cells. The chemical and electronic properties of the extracts and the pure anthocyanidins were examined using spectroscopic studies: ultraviolet (UV), Fourier transform infrared (FT-IR) and gas chromatography coupled with flame ionization detector (GC-FID). Solar cells were fabricated using TiO2 mesoporous film and the extracts and pure compounds as sensitizers. The prominent transitions in U-V spectra were in nature. There were observed shifts in the wavelengths of the absorptions (around 350 to 380 nm) and a characteristic decrease in the absorption between the crude (TCE) and purified (TCP) extracts. The FT-IR spectra of the crude and purified sample have similar absorbances with bathochromic (red) shifts on the hydroxyl group and hypsochromic (blue) shifts on the benzene ring. The GC-FID chromatograms and spectra revealed the presence of six anthocyanidins and their amounts in mg per 100 g of the sample. The results showed that delphinidin was most abundant, and its quantity increases with purification of the extracts, while other anthocyanidins decreased with purification in both extracts. The photovoltaic performances also increase with purity. The best results were obtained with cyanidin-TiO2 ­solar cells with efficiencies up to 2.27%. Key words: Terminalia catappa, anthocyanins, solar cell, efficiency, purification, extracts.

Oxidative stabilization of RBD palm olein under forced storage conditions by old Cameroonian green tea leaves methanolic extract

BackgroundLipid oxidation is responsible for the deterioration of the nutritional and organoleptic qualities of foods. It also leads to the formation in these products of compounds which are harmful for the consumer's health. The synthetic antioxidants used by industries in order to solve this problem are also prone to be toxic and quite volatile at high temperatures. On the other hand, the trend among researchers to replace the synthetic antioxidants with natural ones is increasing because of their potential health benefits. In this study, old Cameroonian green tea leaf methanolic extracts were added in palm olein and its efficiency in delaying the oxidation of oil under forced storage conditions was assessed. MethodsThe plant material was extracted with methanol and its total phenolics content evaluated by colorimetry, followed by the qualitative identification of some phenolic antioxidants by HPLC-DAD and ESI-MS. After preliminary antioxidant studies, the extract was added in oil at concentrations that ranged from 200 to 1800ppm. Oil containing butylated hydroxytoluene (BHT) and oil without antioxidant served as positive and negative controls, respectively. The oxidative stability of these oil samples was evaluated by determining their oxidation induction times on Rancimat (at 110°C) and measuring their oxidative state by the Schaal oven test method during 30days of storage at 70°C. Here, oil samples were collected every 10days and their peroxide, p-anisidine, total oxidation, thiobarbituric acid, iodine values as well as changes in their linoleic acid profile gas chromatography coupled to flame ionization detector (GC/FID) were evaluated. ResultsThe outcomes showed the total phenolics content of the extract to be 53.5mg GAE/g. Gallic acid, epicatechin gallate, gallocatechin and epigallocatechin gallate were the phenolic antioxidants detected. The induction times of palm olein supplemented with the extract (200–1800ppm) were found to be in the range of 24.8–28.9h, while those of control and oil containing BHT were 20.1 and 22.7h, respectively. The extracts, at all concentrations, were also found to be efficient like butylated hydroxytoluene in inhibiting the oxidation of palm olein during 30days of storage at 70°C. ConclusionThe investigations showed that old Cameroonian green tea leaves are a viable source of natural antioxidants for delaying palm olein oxidation.

Aqueous extracts of avocado pear (Persea americana Mill.) leaves and seeds exhibit anti-cholinesterases and antioxidant activities in vitro

Avocado pear (Persea americana Mill.) leaves and seeds are used in traditional medicine for the treatment/management of Alzheimer disease (AD); however, information on the mechanism of actions is limited. This study sought to investigate the effect of P. americana leaf and seed aqueous extracts on some enzymes linked with AD (acetylcholinesterase [AChE] and butyrylcholinesterase [BChE] activities) and their antioxidant potentials in vitro. The inhibitory effects of extracts on AChE and BChE activities and antioxidant potentials (inhibition of Fe2+- and sodium nitroprusside-induced thiobarbiturate reactive species [TBARS] production in rat brain homogenates, radicals [1,1-diphenyl-2-picrylhydrazyl, hydroxyl, and nitric oxide] scavenging and iron [Fe] chelation abilities) were investigated. Phenolic content and phytochemical screening were carried out. Alkaloid profile was also determined using gas chromatography coupled with flame ionization detector (GC-FID). The extracts inhibited AChE and BChE activities and prooxidant-induced TBARS production in a dose-dependent manner, with the seed extract having the highest inhibitory effect and the leaf extract exhibiting higher phenolic content and radical scavenging abilities, but lower Fe chelation ability compared with that of the seed. The phytochemical screening revealed the presence of saponins, alkaloids, and terpenoids in both extracts, whereas the total alkaloid profile was higher in the seed extract than in the leaf extract, as revealed by GC-FID. The anti-cholinesterase and antioxidant activities of avocado leaf and seed could be linked to their phytoconstituents and might be the possible mechanisms underlying their use as a cheap and natural treatment/management of AD. However, these extracts should be further investigated in vivo.

Tributyltin and its Derivative in Water Samples of National Inland Water Way Authority Harbour of Warri, Delta State, Nigeria

Surface water samples were collected and analyzed to evaluate the fate of tributyltin (TBT) and its derivatives dibutyltin (DBT) and monobutyltin (MBT) from National Inland Waterway Authority (NIWA) Harbour, using gas chromatography coupled with flame ionization detection (GC-FID) with detection limit of 0.001 μg/l. The concentrations were in the range of TBT (0.01 μg/l to 0.05 μg/l), DBT (0.01 μg/l to 0.03 μg/l) and MBT (0.01 μg/l to 0.02 μg/l). The total butyltin concentration ranged from 0.04 μg/l to 0.09 μg/l. TBT was generally dominant in most of the samples, suggesting fresh inputs of tributyltin compounds and/or less degradation of TBT. The measured mean concentrations in surface water samples exceeded the ecotoxicological benchmark of 0.01 μg/l recommended by US Environmental Protection Agency (USEPA) indicative of potential environmental risk. This survey provides baseline data on tributyltin compound contamination in National Inland Waterway Authority (NIWA) Harbour and suggests further environmental monitoring of other Nigeria harbours.

English

Lantana camara L. is considered a weed, but is used in agriculture and traditional medicine due to its different pharmacological effects. The objective of this study was to determine the chemical composition and the bioactivity of essential oil from L. camara flowers collected in Boa Vista, Roraima, Brazil. Essential oil was obtained using a Clevenger type apparatus. The oil obtained was analyzed by gas chromatography coupled to flame ionization detector (GC-FID) and gas chromatography coupled to mass spectrometer detector (GC-MS) and its bioactivity was assayed against fungi and bacteria, as well as for acetylcholinesterase inhibition. The chemical composition of essential oil presented major compounds contrasting with the literature, while its bactericidal and fungicidal activity was excellent, reaching over than 90% inhibition against yeast. A potent anti-acetylcholinesterase activity, superior than 77% inhibition, was also observed.   Keywords: Lantana camara, flowers essential oil, antiacetylcholinesterase, antimicrobial

Development of an electroanalytical method for the quantification of aminopyrine in seized cocaine samples

We report the development of a simple and accurate analytical method to detect aminopyrine in seized cocaine samples using a platinum electrode. The quantification of aminopyrine was performed using square wave voltammetry (SWV), where the peak current response was found to increase linearly with aminopyrine concentration over the range 100–1000μmolL−1. The repeatability of the electrode response was determined to be 2.4% (n=15), and the detection limit of the proposed method was estimated to be 22μmolL−1 (3σ/slope). The accuracy of the proposed method was evaluated comparing the measured aminopyrine concentration in seized cocaine sample to the value obtained by gas chromatography coupled to flame ionization detector (GC-FID). An addition and recovery protocol in seized cocaine samples was also performed.

Modelling the Kinetics of Jatropha Oil Transesterification

Kinetics of a chemical reaction provides an important means of determining the extent of the reaction and in reactor designs. Transesterification of jatropha oil with methanol and sodium hydroxide as a catalyst was conducted in a well mixed reactor at different agitation speeds between 600 and 800 rpm and temperature range between 35°C and 65°C. The effect of variation of temperature and mixing intensity on rate constants were studied. The initial mass transfer controlled stage was considered negligible using the above impeller speeds and second order mechanism was considered for the chemically controlled kinetic stage. Samples were collected from the reaction mixture at specified time intervals and quenched in a mixture of tetrahydrofuran (THF) and sulphuric acid. The mixture was centrifuged at 2000 rpm for 15 minutes and the methyl ester was separated from the glycerol. The ester was washed with warm water (50°C), dried and analysed using gas chromatography coupled with flame ionization detector (GC/FID) to determine free and total glycerine and methyl ester. A mathematical model was fitted using second order rate law. High temperature and high mixing intensity increased reaction rates. The model fitted well with a high correlation coefficient (R2) of 0.999.

Flavonoid profile, anthocyanin, carotenoid, sugar and vitamin compositions of Lonchocarpus sericeus seeds

This study reports analyses of flavonoid profile, anthocyanin, sugar, carotenoid and vitamin compositions in Lonchocarpus sericeus (L. sericeus) seeds. Flavonoid profile, anthocyanin, sugar, carotenoid were determined with gas chromatography coupled with flame ionization detector (GC-FID) while vitamins were determined using pulse flame photometric detector (GC-PTPD). Total flavonoid concentration of L. sericeus seeds was 815.86 mg/100g and its profile consists of flavonol (72.5 %), flavanones (19.3 %), flavones (7.25 %), flavanol (0.93 %) and isoflavones (0.02 %). Quercetin was the most abundant with 28.8 %. L. sericeus seeds composed of 80.5 % disaccharides and 19.5 % monosaccharide with sucrose having 80.4 % abundance. Total vitamin, carotenoid and anthocyanin contents of the seeds were 70.32 mg/100g, 102.18 μg/100g and 12.18mg/100g respectively. Vitamin E (33.3 %), β-carotene (65.4 %) and cyanin (30.3 %) had highest abundance in vitamins, carotenoids and anthocyanins respectively. These results show that the seeds of L. sericeus have intrinsic sweetness and can scavenge for free radicals.

Estimation of unidentified non-methane hydrocarbons in urban air based on highly correlated compound pairs

Gas Chromatography coupled with Flame Ionization Detector (GC-FID) is used worldwide for non-methane hydrocarbons' (NMHCs) monitoring. Being a non-selective detector, identification and coelution problems may hamper the reliability of data. An estimation method was developed, based on the correlation of easily measured NMHCs with those unknowns. Correlations were calculated from data obtained with a Gas Chromatograph coupled with a Mass Spectrometer Detector (GC-MSD) after gathering more than 1500 hourly mixing ratio data of 67 NMHCs. The method was developed and validated for an urban area but it may be adapted and applied to other locations. Now it is possible to estimate mixing ratios of some important ozone precursors previously not resolved with the GC-FID, such as 2,2,4-trimethylpentane and 1,2,3-trimethylbenzene. As a result, a six year-long database was enlarged by 34% allowing for a more accurate calculation of the total reactivity and NMHCs’ ozone forming potential.

A solid phase microextraction coating based on ionic liquid sol–gel technique for determination of benzene, toluene, ethylbenzene and o-xylene in water samples using gas chromatography flame ionization detector

Ionic liquid mediated sol–gel sorbents for head-space solid phase microextraction (HS-SPME) were developed for the extraction of benzene, toluene, ethylbenzene and o-xylene (BTEX) compounds from water samples in ultra-trace levels. The analytes were subsequently analyzed with gas chromatography coupled to flame ionization detector (GC-FID). Three different coating fibers were prepared including: poly(dimethylsiloxane) (PDMS), coating prepared from poly(dimethylsiloxane) in the presence of ionic liquid as co-solvent and conditioned at a higher temperature than decomposition temperature of ionic liquid (PDMS-IL-HT) and coating prepared from poly(dimethylsiloxane) in the presence of ionic liquid as co-solvent and conditioned at a lower temperature than decomposition temperature of ionic liquid (PDMS-IL-LT). Prepared fibers demonstrate many advantages such as high thermal and chemical stabilities due to the chemical bonding of the coatings with the silanol groups on the fused-silica surface fiber. These fibers have shown long life time up to 180 extractions. The scanning electron micrographs of the fibers surfaces revealed that addition of ionic liquid into the sol solution during the sol–gel process increases the fiber coating thickness, affects the form of fiber structure and also leaves high pores in the fiber surface that cause high surface area and therefore increases sample capacity of the fibers. The important parameters that affect the extraction efficiency are desorption temperature and time, sample volume, extraction temperature, extraction time, stirring speed and salt effect. Therefore these factors were investigated and optimized. Under optimal conditions, the dynamic linear range with PDMS-IL-HT, PDMS and PDMS-IL-LT fibers were 0.3–200,000; 50–200,000 and 170–150,000pgmL−1 and the detection limits (S/N=3) were 0.1–2 and 15–200 and 50–500pgmL−1, and limit of quantifications (S/N=10) were 0.3–8 and 50–700 and 170–1800, respectively. The relative standard deviations (RSD) for one fiber (repeatability) (n=5), were obtained from 3.1 up to 5.4% and between fibers or batch to batch (reproducibility) (n=3) in the range of 3.8–8.5% for three fibers. The developed method was successfully applied to the real water samples while the relative recovery percentages obtained for the spiked water samples at 20pgmL−1 were from 91.2 to 103.3%.

Degradation products of proguanil — 4-chloroaniline and related components with regard to genotoxicity

AbstractIn the event of genotoxic impurities in drug products, knowledge of the origin and fate of these components is of particular importance. In the present study, commercially available proguanil tablets (Paludrine®) were investigated in respect of formation of the main degradation product, 4-chloroaniline (PCA), which is known to be genotoxic. The investigations made use of high performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) and gas chromatography coupled with flame ionisation detection (GC-FID) systems. In addition, proposals for the structure of further proguanil degradation products were developed based on results obtained by mass spectroscopy (HPLC-MS). Database analysis using DEREK, MCASE, and Vitic was performed to obtain an initial toxicological evaluation of the proposed chemical structures. Finally, the absence of the newly established structures in stored proguanil tablets was verified.