Analytical Quality Parameters Research Articles

Solvents in the industrial synthesis of naphazoline nitrate: implementation of the principles of "Green chemistry" and analysis

The aim: implementation of the principles of green chemistry by regenerating the synthesis solvent 1,2,4-trichlorobenzene and reusing it during the synthesis of the Naphazoline nitrate substance. Study of the influence of the regenerated solvent on the quality of the final product by controlling analytical quality parameters. Development of a method for the quantitative determination and validation of synthesis solvents in a substance. Materials and methods: samples of the substance were synthesized according to the optimized proprietary technology of Farmak JSC. The obtained batches of fresh and regenerated 1,2,4-trichlorobenzene were analyzed according to the monograph of the European Pharmacopoeia on Naphazoline nitrate 0147. Results: the possibility of using regenerated 1,2,4-trichlorobenzene for the synthesis of the substance Naphazoline nitrate has been proven. It is shown that the regenerated solvent does not have a negative effect on the profile of impurities and the polymorphic form of the substance. Analytical quality parameters met the requirements of the internal specification and the requirements of the European Pharmacopoeia monograph. The developed and validated method of quantitative determination of synthesis solvents makes it possible to determine them at the required level. Conclusions: the introduction of regenerated 1,2,4-trichlorobenzene into the synthesis scheme made it possible to significantly reduce the amount of waste per 1 kg of product, which in turn significantly reduced the negative impact on the environment. Analytical quality parameters for regenerated 1,2,4-trichlorobenzene meet the requirements of the internal specification. Industrial series obtained on the regenerated solvent meet the requirements of the monograph of the European Pharmacopoeia. The polymorphic form of the substance batches manufactured on regenerated 1,2,4-trichlorobenzene corresponds to the polymorphic form of the substance batches manufactured on the fresh solvent. The obtained results on the influence of the regenerated solvent on the profile of impurities in the finished substance show the similarity of the profile of the series manufactured on both solvents. According to the requirements of ICH Q3C Impurities: Guideline for residual solvents, a method for quantitative determination of the residual content of 1,2,4-trichlorobenzene in the final product by gas chromatography was developed and validated. The absence of synthesis solvents at the limit of detection is shown

Method for the analysis of volatile compounds in virgin olive oil by SPME-GC-MS or SPME-GC-FID

During the course of the EU H2020 OLEUM project, a harmonized method was developed to quantify volatile markers of the aroma of virgin olive oil with the aim to support the work of sensory panel test to assess the quality grade. A peer validation of this method has been carried out, with good results in terms of analytical quality parameters. The method allows the quantification of volatile compounds by SPME-GC with two possible detectors, flame ionization detector and mass spectrometry, depending on the technical facilities of the labs applying this method. The method was optimized for the quantification of 18 volatile compounds that were selected as being markers responsible for positive attributes (e.g. fruity) and sensory defects (e.g. rancid and winey-vinegary). The quantification is carried out with calibration curves corrected by the internal standards. Additionally, a protocol is provided to prepare the calibration samples. This procedure enhances reproducibility between labs since one of the main sources of errors is the application of different procedures in calibration.

Conducting polymer applied in a label-free electrochemical immunosensor for the detection prostate-specific antigen using its redox response as an analytical signal

A label-free electrochemical inmunosensor based on specific antibody immobilization was developed attached to an aminophenylboronic/poly-indole-6-carboxylic acid-modified electrode (APBA/6-PICA/GCE) for detection of the cancer biomarker, prostate-specific antigen (PSA). The optimal conditions for developing a reproducible bioplatform with excellent stability were determined, focusing on time and incubation temperature. Guided antibody immobilization was carried out using APBA and shown to improve the antigen-antibody affinity. Following the intrinsic redox response of 6-PICA, which corresponds to the electrode doping-undoping charge transfer process, this was chosen as an analytical electrochemical signal using square wave voltammetry (SWV). Cyclic voltammetry, electrochemical impedance spectroscopy and SWV were used in the characterization in the step-by-step optimal construction of the immunosensor and PSA detection. The calibration curve shows a linear range between 0.50 and 100.0 ng·mL −1 , with a limit of detection (LOD) of 0.11 ng·mL −1 , and a limit of quantification (LOQ) of 0.33 ng·mL −1 , respectively. Also, an affinity constant (Ka) between specific monoclonal antibody and PSA was determined at 6.37·10 9 M −1 . These analytical quality parameters propose that the bioplatform can be used to detect PSA concentrations within clinically relevant levels.

Three medicinal Corydalis species of the Himalayas: Their ethnobotany, pharmacognosy, phytochemistry and pharmacology

Herbal medicines including the scholarly Bhutanese Sowa Rigpa medicine (BSM) contribute significantly to primary health care services and play a considerable part in modern drug discovery. BSM, which was integrated with modern health care system in 1967, currently uses more than 200 species of medicinal plants including three closely related members of the Corydalis species; Corydalis calliantha, C. crispa, and C. dubia. Maintaining the quality of these medicinal plants has been always challenging due to adulterants and also due to lack of traditional quality control parameters that could distinguish closely related species. Therefore there is an urgent need to develop reliable analytical methods and quality parameters. Given the significant medicinal properties attributed to the three Corydalis species which are extensively used in BSM, a thorough literature review was performed to investigate their existing quality control parameters including: 1) morphological assessment, 2) habitat and ecological evaluation, 3) macroscopical and microscopical examination, 4) physiochemical limit setting and comparative high-performance thin layer chromatography (HPTLC) profiling, and 5) phytochemical and biological activities. The study revealed that there are distinct species-specific features including ecological adaptation, micromorphology, anatomy, phytochemical values and HPTLC profiles presented by each Corydalis species, and that these quality parameters support traditional quality screening processes in BSM.

A multi-residue method for GC-MS determination of selected endocrine disrupting chemicals in fish and seafood from European and North African markets

An integrated study was conducted to determine the presence of six types of endocrine disrupting chemicals (bisphenol A, triclosan, two alkylphenols, two phenylphenols, eleven organophosphorus pesticides and seven parabens) in the fish and seafood samples from Europe and North Africa. The proposed method involves ultrasound-assisted extraction followed by continuous solid-phase extraction prior to GC–MS analysis. Analytical quality parameters such as linearity, accuracy, precision, sensitivity and selectivity were all good. Limits of detections ranged from 0.5 to 20.0 ng/kg. The relative standard deviation was lower than 7.5% and recoveries ranged from 84 to 105%. The method was successfully used to determine the target analytes in 20 fish and seafood samples from different fish shops and supermarkets in Europe and North Africa. Analyte contents spanned the range 4.6–730 ng/kg and were all below the maximum legally allowed limits. EDCs most frequently found in the samples analysed were dichlorvos, 2-phenylphenol and nonylphenol.

Identification of novel natural inhibitors of snake venom nucleotidases using a structure-based molecular docking study

A new methodology for caffeine determination was developed based on the quenching effect on fluorescent emission of the molecule of Bovine Serum Albumin at λem = 338 nm (λex = 280). A flow injection disposition was designed improving significantly the sampling rate to 60 samples/h using potassium dihydrophosphate 5 · 10− 3 mol L− 1 buffer (pH 6.8) as carrier and flow rate of 1.5 mL min− 1. The experimental and instrumental conditions that influence on analytical quality parameters were systematically investigated, as consider: buffer nature and concentration, fluorophore nature and concentration, and carrier flow rate. The proposal is simple, fast, inexpensive and precise, with a linear range from 6.68 · 10− 6 to 4.0 · 10− 3 mol L− 1 and SD of 0.0668, under optimized conditions. Methodology sensibility and selectivity allowed a variety of sample analyses. It was successfully applied to caffeine quantification in energy drinks, dietary supplements and sliming infusion samples without previous treatment.

Comparison of two analytical methods validated for the determination of volatile compounds in virgin olive oil: GC-FID vs GC-MS

The utility of volatile compounds to explain virgin olive oil aroma descriptors is fully accepted and demanded by the olive oil sector. However, the methodology, and particularly the kind of detector to be used, is a matter of discussion because the high number of volatiles and their different nature. The SPME-GC-MS method has recently been validated for the most relevant volatiles but SPME-GC-FID method still needs to be validated to evaluate its performance in this application. A comparison between these two GC methods in determining 26 volatiles has been carried out in terms of analytical quality parameters (repeatability, intermediate precision, calibration curves, limits of detection and quantification, linear working ranges, selectivity and sensitivity). Good selectivity, linearity and higher upper values of the working range are the main advantages of SPME-GC-FID versus low bottom values of working ranges, better sensitivity and lower limits of detection and quantification of SPME-GC-MS. The limit of blank associated to each individual volatile was also determined and it allowed perfecting the empirical limit of detection. This procedure was carried out for SPME-GC-FID, which resulted in 21 volatiles with empirical limits of detections lower than their odor thresholds, and hence they can be used as markers of virgin olive oil sensory descriptors. Finally, with all the analytical quality parameters checked, a practical example of the ability of the volatiles quantified by SPME-GC-FID to discriminate the different categories (extra-virgin, virgin and lampante) and their main aroma descriptors is also provided.

A study of the differences between trade standards inside and outside Europe

The definitions of olive oil categories are common or very similar for all the international regulatory bodies, and in many cases the text is even literally the same. However, the values of some parameters which chemically define the different categories do not have the same degree of agreement. These disagreements mean a difficult task for importers and exporters who have to deal with these differences when they need to defend the quality and genuineness of their product. This work analyzes the differences found when scrutinizing the current trade standards and regulations from a critical viewpoint, with comments and useful tips for improving the current International Olive Council methods when possible, as well as alternatives from non targeted techniques. The values of precision associated with the International Olive Council methods are also examined and the need for re-validating methods to update the analytical quality parameters is discussed.

VDZ and ICUMSA — 125 years of scientific work for the sugar industry

Starting from the common roots of the Verein Deutscher Zuckertechniker (VDZ) and the International Commission for Uniform Methods of Sugar Analysis (ICUMSA), which are both allocated in the laboratory of the Verein der Zuckerindustrie (VdZ) in Berlin and can be traced back to its long-term Director Prof. Dr. Alexander Herzfeld, the continuous development of analytical methods, which have been harmonised and standardised worldwide by the ICUMSA, is reviewed. National and international cooperation and information exchange of all involved parties is emphasised as a prerequisite, which was defined as a target already in the first constitutions and bylaws of both, VDZ and ICUMSA. A review of the first and up till now most important achievement of ICUMSA, the international standardisation of the polarimetric determination of sugar contents in 1900, is extended by a description of further amendments till 1994. The determination of colour, an important topic for ICUMSA since the beginning, is highlighted amongst various analytical quality parameters of sugar. Standardisation of analytical ICUMSA methods today includes statistical validations based on collaborative studies, following the protocols of the International Union for Pure and Applied Chemistry (IUPAC).

Caffeine determination by flow injection analysis employing Bovine Serum Albumin as a fluorophore

A new methodology for caffeine determination was developed based on the quenching effect on fluorescent emission of the molecule of Bovine Serum Albumin at λem=338nm (λex=280). A flow injection disposition was designed improving significantly the sampling rate to 60samples/h using potassium dihydrophosphate 5·10−3molL−1 buffer (pH6.8) as carrier and flow rate of 1.5mLmin−1. The experimental and instrumental conditions that influence on analytical quality parameters were systematically investigated, as consider: buffer nature and concentration, fluorophore nature and concentration, and carrier flow rate. The proposal is simple, fast, inexpensive and precise, with a linear range from 6.68·10−6 to 4.0·10−3molL−1 and SD of 0.0668, under optimized conditions. Methodology sensibility and selectivity allowed a variety of sample analyses. It was successfully applied to caffeine quantification in energy drinks, dietary supplements and sliming infusion samples without previous treatment.

English

“Chemlali” is the main olive variety cultivated in Tunisia. Seasonal factors such as rainfall and temperature vary year to year influencing the composition and quality of virgin olive oil. This work aims to investigate the effect of the seasonal climatic variations on the quantity and the quality characteristics (free acidity, specific ultraviolet absorbance K232 and K270, fatty acid composition, chlorophylls and total phenols) of Tunisian “Chemlali” olive oil. Water and oil content increased with increasing rainfall and temperature respectively. The seasonal variations of climatic factors within the growing region did not affect the main legal quality indices of all oil samples. K232, total phenol contents and oxidative stability increased at high temperature, while K270 and chlorophyll content decreased. Key words: Analytical quality parameters, chlorophyll, fatty acid composition, Olea europaea L., rainfall, temperature, total phenols.

Sensitivity improvement of a sandwich-type ELISA immunosensor for the detection of different prostate-specific antigen isoforms in human serum using electrochemical impedance spectroscopy and an ordered and hierarchically organized interfacial supramolecular architecture

A gold millielectrode (GME) functionalized with a mixed (16-MHA + EG3SH) self-assembled monolayer (SAM) was used to fabricate an indirect enzyme-linked immunosorbent assay (ELISA) immunosensor for the sensitive detection of prostate-specific antigen (PSA), a prostate cancer (PCa) biomarker, in human serum samples. To address and minimize the issue of non-specific protein adsorption, an organic matrix (amine-PEG3-biotin/avidin) was assembled on the previously functionalized electrode surface to build up an ordered and hierarchically organized interfacial supramolecular architecture: Au/16-MHA/EG3SH/amine-PEG3-biotin/avidin. The electrode was then exposed to serum samples at different concentrations of a sandwich-type immunocomplex molecule (BtnAb-AgPSA-HRPAb), and its interfacial properties were characterized using electrochemical impedance spectroscopy (EIS). Calibration curves for polarization resistance (RP) and capacitance (1/C) vs. total and free PSA concentrations were obtained and their analytical quality parameters were determined. This approach was compared with results obtained from a commercially available ELISA immunosensor. The results obtained in this work showed that the proposed immunosensor can be successfully applied to analyze serum samples of patients representative of the Mexican population.

Effects of essential oils on sprout suppression and quality of potato cultivars

The replacement of synthetic chemical compounds used as potato sprout inhibitors with naturally occurring compounds has been studied in potato varieties used in the processing industry. Sprout suppressant capacity of caraway (Carum carvi, L.), peppermint (Mentha piperita, L.), coriander (Coriandrum sativum, L.) and eucalyptus (Eucalyptus globulus, Labill.) essential oils was studied and compared to the sprout suppressant capacity of chlorpropham (CIPC). For the particular conditions of this study, which used high concentrations, peppermint and coriander essential oils were the most effective sprout inhibitors with inhibition rates of more from 65 to 95% respect to their control. The use of these essential oils also prevented phytopathogenic damage. Analytical quality parameters, such as moisture content and total soluble solids, were not affected by treatment with any of the aromatic essential oils. Sensory analysis revealed no difference in appearance and taste between potatoes treated with essential oils and untreated tubers.

Diversity of Cacao Trees in Waslala, Nicaragua: Associations between Genotype Spectra, Product Quality and Yield Potential

The sensory quality and the contents of quality-determining chemical compounds in unfermented and fermented cocoa from 100 cacao trees (individual genotypes) representing groups of nine genotype spectra (GG), grown at smallholder plantings in the municipality of Waslala, Nicaragua, were evaluated for two successive harvest periods. Cocoa samples were fermented using a technique mimicking recommended on-farm practices. The sensory cocoa quality was assessed by experienced tasters, and seven major chemical taste compounds were quantified by near infrared spectrometry (NIRS). The association of the nine, partially admixed, genotype spectra with the analytical and sensory quality parameters was tested. The individual parameters were analyzed as a function of the factors GG and harvest (including the date of fermentation), individual trees within a single GG were used as replications. In fermented cocoa, significant GG-specific differences were observed for methylxanthines, theobromine-to-caffeine (T/C) ratio, total fat, procyanidin B5 and epicatechin, as well as the sensory attributes global score, astringency, and dry fruit aroma, but differences related to harvest were also apparent. The potential cocoa yield was also highly determined by the individual GG, although there was significant tree-to-tree variation within every single GG. Non-fermented samples showed large harvest-to-harvest variation of their chemical composition, while differences between GG were insignificant. These results suggest that selection by the genetic background, represented here by groups of partially admixed genotype spectra, would be a useful strategy toward enhancing quality and yield of cocoa in Nicaragua. Selection by the GG within the local, genetically segregating populations of seed-propagated cacao, followed by clonal propagation of best-performing individuals of the selected GG could be a viable alternative to traditional propagation of cacao by seed from open pollination. Fast and gentle air-drying of the fermented beans and their permanent dry storage were an efficient and comparatively easy precondition for high cocoa quality.

The application of triticale variety Odyssey as the substitute for malt in wort production

The objective of this work was to investigate the possibility of triticale application as the partial substitute for malt in wort production. For wort production, two series of experiments were performed in which triticale variety Odyssey, from experimental fields, Rimski Sancevi location (Serbia), was used as the substitute for barley malt in grist with and without the addition of commercial enzyme Ultraflo Max (Novozymes, Denmark). Triticale was added in each of the carried series of experiments as the substitute for malt: 0, 10, 20, 30, 40, 50, 60, 70 and 80% in grist. Experiments were carried out on laboratory scale by the application of infusion procedure for wort production. Regarding extract content, triticale variety Odyssey could be used as the substitute for malt up to 60% without the addition of commercial enzyme Ultraflo Max. With the addition of this enzyme triticale variety Odyssey could be used as a substitute for malt up to 80%, regarding the extract content. With the increase in the content of triticale in the grist, viscosity increased. The addition of commercial enzyme Ultraflo Max significantly reduced wort viscosity. The obtained results indicate that worts produced with the addition of triticale variety Odyssey to grist yielded good analytical quality parameters.

Effect of 1-methylcyclopropene on the sensory, visual, and analytical quality of greenhouse tomatoes

Sensory and analytical quality parameters were measured to evaluate the effect of 1-methylcyclopropene (1-MCP) on hothouse tomatoes ( Lycopersicon esculentum Mill., cv. Rapsodie). Commercially grown tomatoes, harvested at the ‘pink’ maturity stage, were treated with 250 nL L −1 1-MCP for 8 h at 15 °C and held at 15 °C for a minimum of 5 d, prior to ripening at 22 °C for 5–8 d. This regime simulated storage conditions used by distributors, retailers, and consumers. Fruit quality parameters [color ( L, a, b), weight, soluble solids, titratable acidity [H +], pH, expressed juice and tomato color index (TCI)] were determined. Sensory analysis was conducted to evaluate perceived flavor (aroma/taste), texture and visual attributes over the ripening period. Treated and untreated fruit were compared for intensity of aroma/flavor (vegetative aroma, ripe tomato aroma, tomato flavor and sourness), texture (firmness, mealiness) and visual attributes [external color (redness, greenness), internal color (redness, greenness), gel color (redness, greenness), juice color (redness, greenness), seed size] by eight judges in duplicate, in five sensory sessions. Statistical contrasts were used to determine differences between 1-MCP treated and untreated fruit, as well as between ‘ripe’ and ‘advanced maturity’ 1-MCP fruit. The 1-MCP treated fruit differed from the control fruit in textural and visual attributes, but not in flavor attributes. Treated fruit had a reduced red color, less red gel color, smaller seed size and greater mealiness. These changes were reflected by concomitant changes in pH, L, b and TCI values. Mealiness was positively correlated ( r = 0.824, p < 0.01) with TCI for 1-MCP treated fruit, suggesting that 1-MCP influenced cell wall integrity during the delayed maturation process. However, it was unknown if this textural changes would be large enough to influence consumer acceptability of the fruit, and warrants further investigation.

Impact of pesticides used in agriculture and vineyards to surface and groundwater quality (North Spain)

An environmental monitoring program was carried out to determine the impact of eight pesticides on the surface and groundwater quality of agricultural areas within the Ebro, Duero and Miño river basins. Three triazines and their desethyl degradation products, metolachlor and metalaxyl, were monitored during 18 months in 63 sites. Solid-phase extraction (SPE) using OASIS HLB 60 mg cartridges and gas chromatography–mass spectrometry (GC–EI-MS) provided good analytical quality parameters and limits of quantification of 0.01 μg/L. Environmental data were assessed using descriptive statistical analysis and multivariate data analysis with principal component analysis (PCA) to elucidate the relevant contamination patterns and provide a description of their seasonal trends, according to the pesticide application timing. Duero was the site with the highest frequency of detection and highest concentration levels, followed by the Ebro and Miño basins. The frequency of detection of the studied compounds, considering all surface and groundwater samples, was atrazine>desethylatrazine>simazine>desethylsimazine>metolachlor>desethylterbuthylazine>terbuthylazine>metalaxyl. Over all results, and taking into consideration the European Union (EU) maximum residual limit of pesticides in groundwater, only 12% of the results exceeded the 0.1 μg/L limit. However, sporadic high levels up to 2.46 μg/L in groundwater and 0.63 μg/L in surface water were detected. PCA permitted to state that Duero and Ebro river basins were especially affected by a contamination pattern dominated by atrazine, the Ebro river basin being occasionally affected by a contamination pattern dominated by simazine. Only trace levels were rarely detected in the Miño river basin. Groundwater levels were higher than surface water levels for the studied pesticides.

Development of an ultraperformance liquid chromatography method for improved determination of additives in polymeric materials

An analytical method for the simultaneous separation and quantitation of ten colorants and six antioxidants used as polymer additives has been developed by transferring chromatographic conditions from two independent HPLC methods to a single ultraperformance liquid chromatography system. An experimental design was carried out to achieve the best elution gradient for separation of all the studied compounds with the best possible peak resolution and in the shortest possible analysis time. The new method gives good values for the analytical quality parameters evaluated.

The application of triticale malt as the substitute for barley malt in wort production

The aim of this work was the investigation of wort production for beer by the application of triticale malt, as the partial substitute for barley malt in grist. For wort production, three series of experiments were carried out in which malts were produced from three different triticale varieties taken from experimental fields Rimski Sancevi location (Serbia), crop 2006. Experiments were carried out on laboratory scale by applying infusion procedure for wort production. The obtained results indicate that the application of triticale malt gave worts that had good analytical quality parameters.

ECOLOGICAL APPLE PRODUCTION: A COMPARISON OF ORGANIC AND INTEGRATED APPLE-GROWING

In 1995, an experiment was planted at Wadenswil for comparing organic and integrated apple production. The overall goal of this experiment was to develop a data set which allows for an objective overall comparison of the two production concepts. Horticultural, ecological and economical traits were looked at. In practical terms, the study should particularly clarify how suitable the two systems are for producing marketable fresh fruit under Swiss conditions. The approach of an on-station comparison with a split-plot design with 3 replicate blocks and the factors “production system” (1st factor) and “variety” (2nd factor) was chosen. Ninety-four percent of Swiss apple acreage is managed according to integrated production, and 5% according to organic guidelines 2001. Conventional production is therefore lacking practical relevance and was not included in this trial. Cultivars Boskoop, Pommes Cloche, Idared and Resi were planted on rootstock M9 at a 3.4 by 1.4m spacing. The crop management was dynamically adapted every year according to the most advanced crop management technology that is appropriate in the particular in situ situation of the trial and that is permitted by the most recent Swiss guidelines for each of the two production systems. In particular, parameters of tree growth, fruit growth, yield and fruit quality, crop protection, crop economy and crop ecology were assessed. In 2001, additional analytical fruit quality parameters were measured and extensive sensory tests were performed. This study provides the first scientific comparison of organic and integrated apple production under European conditions. The paper presents preliminary conclusions while the last cropping season of the experiment is still on-going and final data analyses will be possible in 2003.