Multivariate approaches for stability control of the olive oil reference materials for sensory analysis - part II: applications.

BACKGROUND: The organoleptic quality of virgin olive oil depends on positive and negative sensory attributes. These attributes are related to volatile organic compounds and phenolic compounds that represent the aroma and taste (flavour) of the virgin olive oil. The flavour is the characteristic that can be measured by a taster panel. However, as for any analytical measuring device, the tasters, individually, and the panel, as a whole, should be harmonized and validated and proper olive oil standards are needed. RESULTS: In the present study, multivariate approaches are put into practice in addition to the rules to build a multivariate control chart from chromatographic volatile fingerprinting and chemometrics. Fingerprinting techniques provide analytical information without identify and quantify the analytes. This methodology is used to monitor the stability of sensory reference materials. CONCLUSION: The similarity indices have been calculated to build multivariate control chart with two olive oils certified reference materials that have been used as examples to monitor their stabilities. This methodology with chromatographic data could be applied in parallel with the 'panel test' sensory method to reduce the work of sensory analysis. © 2018 Society of Chemical Industry.

Robust Multi-Objective Global Optimization of Stochastic Processes With a Case Study in Gradient Elution Chromatography.

A novel algorithm for robust multi-objective process optimization under stochastic variability of environmental variables is introduced and applied to a case study in gradient elution chromatography. Process variability is accounted for by simultaneously optimizing several scenarios with random but fixed values of the environmental variables. These iterative optimizations are synchronized by planning the same experiments for all scenarios. Experiments are designed by maximizing the cumulative expected hypervolume improvement as predicted by several Gaussian process regression models. A straightforward method is presented for estimating the expected Pareto front and its variability based on the resulting data that maintains traceability of the corresponding process parameters. This information is required for robust process optimization, that is, determination of Pareto optimal processes that fulfil specific minimal criteria with a certain confidence. The presented algorithm can generally be applied to both in silico and wet lab experiments but involves an increased experimental effort as compared to the deterministic case.

Comparação entre três métodos analíticos para determinação de soro em leite cru refrigerado / Comparison of three analytical methods to determine serum in refrigerated raw milk

O objetivo deste experimento foi comparar três métodos analíticos para determinação de soro em leite cru refrigerado: cromatografia líquida de alta eficiência, ninidrina ácida e colorimétrico adaptado. Foram coletadas 100 amostras de leite cru refrigerado de tanques de expansão. Estas, quando submetidas à análise pelo método da ninidrina ácida, apresentaram 10 (14,7%) amostras negativas e 58 (85,3%) positivas. O teor médio de ácido siálico encontrado na técnica da ninidrina foi de 5,58(g/mL, com valor mais frequente de 2,70(g/mL. Das 68 amostras negativas pela cromatografia líquida de alta eficiência, duas foram positivas (2,94%) e 66 (97,06%) negativas, quando analisadas pelo método colorimétrico. A frequência relativa de amostras positivas foi de 32%, com a CLAE apresentando a maior média de soro (14,37%), seguida do método colorimétrico (5,28%) e o da ninidrina ácida (3,12%). A técnica de cromatografia líquida de alta eficiência diferiu dos métodos de ninidrina ácida e colorimétrico, enquanto os métodos da ninidrina e colorimétrico não diferiram entre si, podendo ambos serem utilizados como metodologias de triagem. Entre as três técnicas, a cromatografia líquida de alta eficiência foi a metodologia mais sensível na detecção e quantificação do soro em leite cru refrigerado.(AU)

The objective of this study was to compare three analytical methods to determine serum in refrigerated raw milk. High-performance liquid chromatography (HPLC), acidic and colorimetric ninhydrin methods were applied. A collection of 100 samples of raw milk from cooled expansion tanks took place. The results showed that 10 samples (14.7%) were negative and 58 (85.3%) were positive for the acidic ninhydrin method. The mean sialic acid content found in the ninhydrin technique was 5.58µg/mL, with a more frequent value of 2.70µg/mL. From all 68 HPLC negative samples, two were positive (2.94%) and 66 (97.06%) negative to the colorimetric method. The relative frequency of positive samples was 32%, HPLC had the highest mean serum levels (14.37%), followed by the colorimetric method (5.28%) and acid ninhydrin (3.12%). The high-performance liquid chromatography method was different from the acid and colorimetric ninhydrin methods. The ninhydrin and colorimetric methods were not different from each other, both of which could be used as screening methodologies. Among the three techniques, HPLC was the most sensitive methodology for the detection and quantification of serum in refrigerated raw milk.(AU)

CHROMATOGRAPHIC TECHNIQUES IN PHARMACEUTICAL ANALYSIS IN POIAND: HISTORY AND THE PRESENCE ON THE BASIS OF PAPERS PUBLISHED IN SELECTED POLISH PHARMACEUTICAL JOURNALS IN XX CENTURY.

For a long time, chromatographic techniques and techniques related to them have stimulated the development of new procedures in the field of pharmaceutical analysis. The newly developed methods, characterized by improved metrological parameters, allow for more accurate testing of, among others, the composition of raw materials, intermediates and final products. The chromatographic techniques also enable studies on waste generated in research laboratories and factories producing pharmaceuticals and parapharmaceuticals. Based on the review of reports published in Polish pharmaceutical journals, we assessed the impact of chromatographic techniques on the development of pharmaceutical analysis. The first chromatographic technique used in pharmaceutical analysis was a so-called capillary analysis. It was applied in the 1930s to control the identity of pharmaceutical formulations. In the 1940s and 1950s, the chromatographic techniques were mostly a subject of review publications, while their use in experimental work was rare. Paper chromatography and thin layer chromatography were introduced in the 1960s and 1970s, respectively. These new analytical tools have contributed to the intensive development of research in the field of phytochemistry and the analysis of herbal medicines. The development of colunm chromatography-based techniques, i.e., gas chromatography and high performance liquid chromatography took place in the end of 20th century. Both aforementioned techniques were widely applied in pharmaceutical analysis, for example, to assess the stability of drugs, test for impurities and degradation products as well as in pharmacokinetics studies. The first decade of 21" century was the time of new detection methods in gas and liquid chromatography. The information sources used to write this article were Polish pharmaceutical journals, both professional and scientific, originating from the interwar and post-war period, i.e., "Kronika Farmaceutyczna", "Farmacja Wspólczesna", "Wiadomosci Farmaceutyczne", "Acta Poloniae Pharmaceutica", "Farmacja Polska", "Dissertationes Pharmaceuticae", "Annales UMCS sectio DDD Phamacia". The number of published works using various chromatography techniques was assessed based on the content description of individual issues of the journal "Acta Poloniae Pharmaceutica".

Orthogonal separations: Comparison of orthogonality metrics by statistical analysis.

Twenty orthogonality metrics (OMs) derived from convex hull, information theory, fractal dimension, correlation coefficients, nearest neighbor distances and bin-density techniques were calculated from a diverse group of 47 experimental two-dimensional (2D) chromatograms. These chromatograms comprise two datasets; one dataset is a collection of 2D chromatograms from Peter Carr's laboratory at the University of Minnesota, and the other dataset is based on pairs of one-dimensional chromatograms previously published by Martin Gilar and coworkers (Waters Corp.). The chromatograms were pooled to make a third or combined dataset. Cross-correlation results suggest that specific OMs are correlated within families of nearest neighbor methods, correlation coefficients and the information theory methods. Principal component analysis of the OMs show that none of the OMs stands out as clearly better at explaining the data variance than any another OM. Principal component analysis of individual chromatograms shows that different OMs favor certain chromatograms. The chromatograms exhibit a range of quality, as subjectively graded by nine experts experienced in 2D chromatography. The subjective (grading) evaluations were taken at two intervals per expert and demonstrated excellent consistency for each expert. Excellent agreement for both very good and very bad chromatograms was seen across the range of experts. However, evaluation uncertainty increased for chromatograms that were judged as average to mediocre. The grades were converted to numbers (percentages) for numerical computations. The percentages were correlated with OMs to establish good OMs for evaluating the quality of 2D chromatograms. Certain metrics correlate better than others. However, these results are not consistent across all chromatograms examined. Most of the nearest neighbor methods were observed to correlate poorly with the percentages. However, one method, devised by Clark and Evans, appeared to work moderately well. Products of OMs show better correlation with the percentages than do single OMs. Product OMs that utilize one discretized metric paired with the convex hull relative area, which measures overall zone occupancy, perform well in determining the "best" chromatogram among both datasets and the combined dataset. A definition of chromatographic orthogonality is suggested that is based on maximizing the values of OMs or OM products. This optimization criterion suggests using the product of a global metric that measures the utilization of separation space (e.g., the convex hull relative area) and a local metric that measures peak spacing (e.g., the box-counting fractal dimension). The "best" column pairs for 2D chromatography are chosen by the product of these OMs.

Ultrasensitive nanogold probe-based immunochromatographic assay for simultaneous detection of total aflatoxins in peanuts.

An ultrasensitive immunochromatographic (IC) assay for simultaneous detection of total aflatoxins (AFB1, AFB2, AFG1, and AFG2) was developed to meet the requirement for rapidly monitoring aflatoxins in agro-products. The assay was based on a competitive format and its sensitivity was improved by using a novel criterion to screen the optimal amount of monoclonal antibody (MAb) labeled to nanogold particles. The visual detection limits (VDLs) for aflatoxins B1, B2, G1, and G2 in peanut matrix were 0.03, 0.06, 0.12, and 0.25 ng mL(-1), respectively, which were lower than those of published literatures. The results of IC assay were in good agreement with those of high performance liquid chromatography (HPLC) in the analysis of aflatoxins in peanuts, demonstrating the practical applicability of the developed assay in real samples. This qualitative test based on the visual evaluation of results did not require any equipment. Overall, to our knowledge, this is the first report of qualitative detection for total aflatoxins by immunochromatographic assay.

Statistical theory of multiple-site linear wall-adsorption capillary Chromatography.

Based on the mass-balance principle, a particular diffusion equation to describe the movement of solute molecules in the stagnant layer of multiple-site solid surfaces is constructed. From the equation, the moments of residence time in a step on multiple-site surfaces are derived. Similarly, the moments in a step in the mobile phase are also derived from a diffusion-drift equation. According to the probability theory, there exists a general relationship between the moments of an elution curve and the moments in a step. Through this relationship, the expressions of the elution-curve moments are derived from the step moments. In this paper, the details related to multiple-site linear wall-adsorption capillary chromatography are described and added in the equations to determine the step moments. The resultant expressions of the elution-curve moments involve various factors, such as adsorption-desorption rate constants, equilibrium constants, axial and radial dispersions in the mobile phase. Afterwards, the moment expressions are used to analyze the peak tailing. The results show that a small quantity of sites with a slow desorption rate will lead to a large peak asymmetry.

[Concordance between thick blood smear, immunochromatography and polymerase chain reaction for malaria diagnosis]. / Concordancia entre gota gruesa, inmunocromatografía y reacción en cadena de la polimerasa para el diagnóstico de malaria.

INTRODUCTION: The rapid and effective diagnosis of malaria is the determining condition for an appropriate treatment and control of the disease. OBJECTIVE: The sensitivity, specificity and the positive and negative predictive values were evaluated in cases of suspected malaria in Colombia in a comparison of a rapid diagnostic test. the PCR test and the thick blood smear-the traditional gold standard. MATERIALS AND METHODS: A group of 100 patients with symptoms compatible with malaria, were included in the study. They were selected from the following Colombian regions: Urabá, Córdoba, lower Cauca, and relatively fewer from other malaria endemic areas of Colombia including the provinces of Valle, Chocó in the central west of Colombia and Vichada to the east. To each patient the following three tests were performed: the rapid OptiMAL test, the PCR identification and the thick blood smear. The PCR amplified specific DNA sequences with primers designed to identify the genus Plasmodium, and the two species present in Colombia, P. falciparum and P. vivax. RESULTS: The sensitivity of the rapid test versus the thick smear, for the diagnosis of both species of Plasmodium was 93.9% (95% CI: 87-100%) and the specificity was 94.3% (95% CI:.253 85-100%). The PCR compared with the thick smear showed a sensitivity of 100% (95% CI: 99-100%) and a specificity of 97.1% (95% CI: 90-100%). CONCLUSIONS: The sensitivity and specificity of the three tests did not present statistically significant differences. However, the thick blood smear was recommended as the standard test, mainly due to its low cost.

[Chromatographic fingerprint and quality control of traditional Chinese medicines].

The development of modern chromatographic technologies and related chemometric methods in the research of chromatographic fingerprint, and their applications in quality control of traditional Chinese medicines (TCMs) are comprehensively reviewed. Furthermore, we preliminarily discuss the quality control methods and their feasibility to guarantee that the TCMs can be used stably and effectively. A new strategy is proposed to establish the comprehensive relationships between chromatographic fingerprints and their pharmacodynamic (toxicity) information with the help of the techniques of modern chromatography, chemometrics and system biology to reveal the working mechanism of TCMs and then to comprehensively control the quality of TCMs.

Prediction of retention indices of drugs based on immobilized artificial membrane chromatography using Projection Pursuit Regression and Local Lazy Regression.

The relationship between the logarithm of retention indices (log k(IAM)) of 55 diverse drugs in immobilized artificial membrane (IAM) chromatography and molecular structure descriptors was established by linear and non-linear modeling methods--Projection Pursuit Regression (PPR) and lazy learning method-Local Lazy Regression (LLR). The descriptors calculated from the molecular structures by the software CODESSA and a widely accepted property parameter ClogP were used to represent the characteristics of the compounds. The best multi-linear regression (BMLR) method in the CODESSA was used to select the most important molecular descriptors from a large set of descriptors and to develop the linear and non-linear quantitative structure retention relationship (QSRR) models. By comparing these different methods, the LLR model gave the best predictive results for the drugs studied in the present work with the square of correlation coefficient (R(2)) of 0.9540, 0.9305; root mean square error (RMSE) of 0.2418, 0.3949; for the training set and test set, respectively. It was proved that the LLR method was a promising method for QSRR modeling with good predictive capability for the retention indices of drugs in immobilized artificial membrane chromatography, and could be used in other similar chromatography research fields.

Improving sensitivity in chiral supercritical fluid chromatography for analysis of active pharmaceutical ingredients.

Despite its status as the preferred method for routine enantiopurity analysis in pharmaceutical research, supercritical fluid chromatography (SFC) has historically been unsuited for the accurate and precise measurements required for release testing of active pharmaceutical ingredients (APIs) under current good manufacturing processes (cGMPs). Insufficient signal to noise, as compared to HPLC, has heretofore been the major limitation of the chiral SFC approach. We herein describe an investigation into the fundamental limitations and sources of noise in the SFC approach, identifying thermal, electronic, and mechanical sources of noise within the flow cell as key parameters contributing to reduced sensitivity. A variety of instrument modifications are explored, ultimately leading to the development of a new and improved flow cell and other instrument modifications that allow suitable sensitivity and accuracy to carry out GMP release testing for enantiopurity analysis using SFC.

Characterization and comparison of the chromatographic performance of different types of reversed-phase stationary phases.

The chromatographic performance of several base-deactivated stationary phases was evaluated with a specific chromatographic test. Seven basic test compounds, possessing different physico-chemical properties were injected on different supports with two mobile phases: one at pH 7.0 (acetonitrile-phosphate buffer, 40:60, v/v), and the other at pH 3.0 (acetonitrile-phosphate buffer, 15:85, v/v). Chromatographic parameters obtained under these conditions were treated by principal component analysis (PCA) to separate base deactivated supports according to their silanol activity (pH 7.0 mobile phase) and hydrophobic properties (pH 3.0 mobile phase). The information given by the specific test column evaluation was improved with complementary chemometric tools such as hierarchical cluster analysis. The same base deactivated supports were also tested following a general test procedure issued from the literature and obtained fundamental properties (in particular silanol activity and hydrophobicity) were compared with column evaluation obtained with the specific test: results were in good agreement, although the use of the specific test offered a better differentiation between numerous base-deactivated supports.

Statistical power and analytical quantification.

It is suggested that power analysis should be formally incorporated into quantification experiment reports in order to substantiate the conclusions derived from experimental data more effectively. The article addressed the issues of power analysis calculation, sample size estimation and appropriate data reporting in quantitative analytical comparisons. Illustrative examples from the literature are used to show how the described power analysis theory could be applied in practice.

BIS repetita non placent -- a statistical analysis of the number of sample preparations and number of injections required for chromatographic analyses.

This article attempts to answer the question of how many replicate sample preparations and replicate chromatographic injections must be done to provide accurate results in chromatographic analyses of pharmaceuticals. Using a random selection of chromatographic runs obtained with 1-3 replicate preparations and duplicate injections, the variance associated with preparation-to-preparation and injection-to-injection variability were estimated by a mixed-model statistical analysis. The analysis also predicted the probability that two injections of the same sample preparation are not in agreement with each other. Results indicated that, with modern chromatographic equipment, duplicate injections do not improve the precision. The number of replicate preparations needed to provide accurate results for various types of analysis depends on the type of sample and the desired tightness of the specification limits.

[Current situation of the malaria inspection in Jikei University Hospital].

The current situation of the malaria inspection in our laboratory was investigated. Malaria was detected by three different methods, May Giemsa staining(MG), acridine orange staining(AO), and antigen detecting method using NOW ICT Malaria P.f./P.v. kit(Ag). There were 207 requests a year(17.3 per month), and the holiday/night request occupied 12%. Fifteen patients were positive, 5 with plasmodium falciparum (p.f.) and 10 with plasmodium vivax(p.v.), including 3 relapsed cases. All the patients with p.f. were suffered in Africa, and 6 with p.v. were in Southeast Asia, and one with p.v. was in Central America. The rate of coincidence between MG/Ag and MG/AO were 94.4% and 96.9%, respectively. There were 7 samples that were MG negative and Ag positive, but all of these samples were obtained after the initiation of the treatment. There was no sample that showed MG positive and Ag negative. Our data suggested that no difference in detection sensitivity was found between microscopic observation and the antigen detection kit. Thus it would be a very useful and accurate strategy to use this antigen detection kit in a routine laboratory check up.

Fractal fingerprinting of chromatographic profiles based on wavelet analysis and its application to characterize the quality grade of medicinal herbs.

Extracting chemical fingerprints is an important step for representing and interpreting chromatographic data. In this paper, the chromatographic profile is decomposed into components at different resolution levels using wavelet analysis, then the fractal dimensions of these components are computed as the chemical fingerprints. The chromatographic fingerprint is characterized by the vector composed of these chemical fingerprints, which can represent the chemical patterns of different categories of complex samples. Computer simulations reveal that the fractal fingerprints are more stable than the original chromatographic profile data with respect to variations of peak retention time. To demonstrate the validity of this method, the evaluation of the quality of the medicinal herb Angelica sinensis (Oliv.) diels is investigated. Principal component analysis of the fractal fingerprints indicates that samples belonging to the same quality grade are clustered together, while those belonging to different quality grades are separated. Using these fractal fingerprints taken from the chromatographic scans as inputs for an artificial neural network (ANN). The quality grades of two sets of the herbs were verified by cross-validation, indicating that 96.7% of the herbs are correctly identified with respect to their quality grades evaluated by experienced experts, and 100.0% of the herbs are correctly identified with respect to their quality grades determined by pharmacodynamical evaluation.

Usefulness of urinary antigen detection by an immunochromatographic test for diagnosis of pneumococcal pneumonia in children.

We evaluated an immunochromatographic assay detecting pneumococcal antigen in urine samples from children diagnosed with pneumococcal pneumonia. The sensitivity and specificity of the immunochromatographic test with nonconcentrated urine (NCU) were 86.7 and 62.9%, respectively; with concentrated urine (CU), they were 100 and 11.7%, respectively. Pneumococcal antigen was also detected in 42.5% of NCU and 87.1% of CU samples from nasopharyngeal carriers. This is a nonspecific test for the diagnosis of pneumococcal pneumonia in children, particularly the very young.

A highly sensitive quantitative immunochromatography assay for antigen-specific IgE.

We have developed a highly sensitive quantitative enzyme immunochromatography system for antigen-specific IgE, which is clinically important for the diagnosis of allergic diseases. The system uses alkaline phosphatase-labeled anti-IgE antibody (ALP-anti-IgE) and immobilized target antigen, for example cedar pollen antigen, on a membrane. Antigen-specific IgE present in the serum binds the immobilized antigen after complexing with the ALP-anti-IgE. Subsequently, the enzyme substrate migrates to the complex on the antigen line, which is stained blue. The intensity of the staining was analyzed by a quantitative detector, but can also be assessed directly by the naked eye. This system was able to detect 0.2 U/ml of IgE specific for Japanese cedar pollen. The results correlated well (Spearman's rank correlation coefficient, 0.95) to those in AlaSTAT system, which is a reliable enzyme-linked immunosorbent assay (ELISA) method. This antigen-specific IgE assay system is suitable for point-of-care testing.

Tagless extraction-retentate chromatography: a new global protein digestion strategy for monitoring differential protein expression.

A new global protein digestion and selective peptide extraction strategy for the purpose of monitoring differential protein expression, coined as tagless extraction-retentate chromatography, is introduced. Target protein populations are firstly digested under reduced and alkylated conditions, and resultant peptides selectively extracted via covalent attachment to methionine residues by bromoacetyl reactive groups tethered to the surface of glass beads packed in small reaction vessels. After conjugation, reactive beads are stringently washed to remove nonspecifically bound peptides and then later treated with beta-mercaptoethanol to release captured methionine peptides in their nascent state, without complicating affinity tags. Recovered methionine containing peptides are profiled using the surface-enhanced laser desorption/ionization (SELDI) retentate chromatography mass spectrometry (RCMS) method. Selected peptides are further studied employing ProteinChip tandem mass spectrometry (MS/MS) analysis to identify their parent proteins. This approach has been applied to an Escherichia coli lysate model system and has demonstrated facility in reducing global digest complexity, sensitivity to low protein expression levels, and significant quantitative capability. It is envisioned that tagless extraction-RCMS will evolve to be a valuable approach for both basic research and clinical proteomics endeavors.