High-performance Liquid Chromatography Device Research Articles

Evaluation of the amount of residual monomer released from different flowable composite resins

Today, resin materials are used in the restoration of permanent and deciduous teeth or as fissure sealants. The materials can contain different types of monomers (Bis-GMA, UDMA, TEGDMA). These monomers can be released into the oral cavity after polymerization. Residual monomers released from resin-containing restorative materials after polymerization have been reported to have negative effects on mechanical properties. The aim of our study is to evaluate the amount of residual monomers released after polymerization of different flowable composite resin materials using two different modes of LED light source. Composite disc samples (8 mm diameter/2 mm depth) prepared for each material group were polymerized using two different modes of the LED light device (Standard mode and extra power mode). HPLC (High Performance Liquid Chromatography) device was used to measure the amount of residual monomer release at 1 h, 1 day, 3 days and 7 days periods. Pairwise comparison of the differences between the materials was performed by Post-hoc test. For each residual monomer, the Kruskal Wallis test was used to analyze the difference between the materials in standard mode and the difference between the materials in extra power mode. According to the results of the study; Grandio flow flowable composite showed the highest release of TEGDMA and Bis-GMA while SDR® Flow flowable composite showed the lowest release of TEGDMA, Bis-GMA and UDMA. For all materials, the extra power mode resulted in more residual monomer release. TEGDMA and Bis-GMA release was detected in all tested flowable composites at all time periods.

Preparation of Plant-Derived Smoke Stimulating Seed Germination and Quantification of Karrikins Using High Performance Liquid Chromatography (HPLC)

Smoke water (SW) is produced naturally or artificially from burning plant material. It provides the germination of the seeds of many plants and accelerates the growth and development of the plant and is also used in many fields of plant science. SW preparation is a relatively easy and inexpensive method, but a standard method for its preparation has not been developed yet. Therefore, the aim of this research is to develop a low-cost efficient method to produce SW, to standardize it and to measure the amount of the main active biomolecule karrikin (KAR1) by HPLC device. It was also tested and compared in apricot (Prunus armeniaca L.) seeds to determine the best working concentration of the obtained SW and commercially available KAR1. SWs prepared for SW standardization were diluted at 1:100, 1:500, 1:1000, 1:5000 and 1:10000 ratios, and KAR1 was diluted at 0.01 µM, 0.1 µM, 1 µM, 5 µM and 10 µM ratios. In terms of germination, it was determined that the use of 1:1000 (60%) concentration in the SW group and 1 µM (72%) concentration in the KAR1 group was appropriate. This is the first research in which a standard method was developed for obtaining SW. In addition, thanks to the method developed in this research, we think that it will help other researchers since it is the study in which KAR1 substance is the most intense in SW according to the literature.

Estimation of amino acid concentrations in the kidney of albino mice embryo

Amino acids are the basic building block for peptides and proteins. They are raw materials for generating hormones, purines, pyrimidines and vitamins. Amino acids also provide the body with energy through their carbon structures. The study analyzed the amino acid in the kidneys of the albino mice embryo at 17 and 19 gestation days, using a high-performance liquid chromatography device (HPLC). Samples were obtained after removing them from the embryo and placing them in an ice bath to prevent cell lysis and acid loss. The study found 18 amino acids in the kidneys of the albino mice embryo. They are Asparagine (Asn), Glutamine (Glu), Serine (Ser), Glycine (Gly), Threonine (Thr), Histidine (His), Cysteine (Cys), Alanine (Ala), Proline (Pro), Tryptophan (Tryp), Arginine (Arg), Tyrosine (Tyr), Valine (Val), Methionine (Met), Isoleucine (Ile), Leucine (Leu), Phenylalanine (Phe), and Lysine (Iys). Keywords: Amino acid, Mus musculus, Embryo, Kidney.

Biochemical changes and antioxidant capacity of naringin and naringenin against malathion toxicity in Saccharomyces cerevisiae

Flavonoids are rich in seeds, citrus fruits, olive oil, tea and red wine. Citrus flavonoids constitute an important type of flavonoids. Naringin and naringenin belong to flavonoids with known antioxidant and were found to display antioxidant activities. Malathion is an organophosphorus pesticide that has been broadly used throughout the world to control weeds and pests. It has also been used in public health for mosquito control and fruit fly eradication programs. Malathion, naringin, and naringenin were added to be in 40, 80, and 160 mg doses in Saccharomyces cerevisiae cultures mainly used to determine the antioxidant capacity, it is known that they have shown similar results to man. At the end of the experiment, total protein, malondialdehyde (MDA), reduced glutathione (GSH), oxidized glutathione (GSSG), vitamin K, vitamin E, vitamin D, ergosterol, stigmasterol, β-Sitosterol, and fatty acids were analyzed by HPLC (high performance liquid chromatography) and GC (gas chromatography) devices in the tested S. cerevisiae samples. The contents of the yeast cell of octanoic acid (C8:0), lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), palmitoleic acid (C16:1n-7), heptadecanoic acid (C17:0), stearic acid (C18:0), oleic acid (C18:1n-9), and linoleic acid (C18:2n-6) were identified. There were statistically significant changes in total protein, MDA, GSH, GSSG, vitamin K, vitamin E, vitamin D, phytosterol and fatty acid levels. It was determined that naringin and naringenin showed statistically significant decreases against malathion toxicity on these parameters. From this study it is found that, the mitigating effect of naringin against DPPH stable free radical was higher than that of naringenin. Citrus flavonoid, naringin showed promising antioxidant activity which can be used as effective protecting agents against oxidative stress.

Evaluation of four different HPLC devices for hemoglobinopathy screening

Abstract Objective Hemoglobinopathies are a common public health problem in Turkey. In the screening of these disorders in population, cation-exchange high performance liquid chromatography (HPLC) is accepted as the gold standard method. In this study, the aim was to assess four different HPLC devices used in hemoglobinopathy screening. Materials and methods A total of 58 blood samples were analyzed with four different HPLC methods (Bio-Rad variant II, Agilent 1100, Tosoh G8 and Trinity Ultra2 trademarks). Results The comparison study demonstrated a good correlation between the results of each HPLC analyzer and the reference value obtained by averaging all the HbA2 results belonging to the methods tested in the study [ (Tosoh G8 (r=0.988), Bio-Rad variant II (r=0.993), Agilent 1100 (r=0.98) and Trinity Ultra2 (r=0.992) ]. HbA2 determination in the presence of HbE was interfered in both Bio-Rad variant II and Tosoh G8. Conclusion The analyzers were found to have compatible HbA2 results but with accompanying different degrees of proportional and systematic biases. HPLC analyzers may be affected by different hemoglobin variants at different HbA2 concentrations, which is an important point to take into consideration during the evaluation of HbA2 results in thalassemia screening.

Determination of Isoflavones in Nuts, Dried Fruits and Vegetables by High Performance Liquid Chromatography

In this study, the amounts of daidzin, daidzein and genistein of isoflavone components were determined in nuts, dried fruits and vegetables by high performance liquid chromatography (HPLC). Firstly, the extraction conditions like the rate of the aqueous and organic phase, the total volume of the extraction solution, time and rotation per minute of centrifugation were optimizaed. After extraction conditions were specified, the parameters of HPLC device have investigated. The isoflavone components were extracted by a mixture of 0.1% acetic acid and methanol (20:80 v/v), at the room temperature. The chromatographic separation was conducted on C18 with wavelength of 260 nm at 30 oC. The diode array detector was used. The analytical parameters given as the dedection and quantification limits, linearity, precision and accuracy were determined. The relative standard deviation of method was determinated ≤3 % (n=21) and the calibration curse was worked in the range 1-100 mg L-1. The total isoflavone concentration in real samples from Sivas centrum was determined in the range 9.6 ˗ 469.1 μg g-1.

A simple spectrophotometric evaluation method for the hydrophobic anticancer drug paclitaxel

In this work, we demonstrate a simple spectrophotometry approach to more accurately quantify and measure paclitaxel (PTX) concentrations. PTX cannot be precisely quantified when mixed with an aqueous solvent, and carries the risk of undergoing crystal precipitation. It is likely that PTX undergoes numerous interactions with aqueous solvents and enters a supersaturated state due to its low solubility. Therefore, a quantitative method is required to measure PTX for quality control before clinical use. Although several high-performance liquid chromatography (HPLC) methods have been reported to date, not all medical facilities have a clinical laboratory with such HPLC devices and analysis techniques. Spectroscopy is a simple and convenient method; however, calibration standards are prepared with an organic solvent, such as methanol and acetonitrile, which, when mixed with PTX, can cause solvent effects that lead to inaccurate results. We generated a calibration curve of PTX at various concentrations (40%, 50%, 60%, 70%, 80%, 90% and 100%) of methanol and evaluated the relative error from HPLC results. The optimum methanol concentration for quantification of PTX was 65.8%, which corresponded to the minimum relative error. The detection limit and quantification limit were 0.030 μg/mL and 0.092 μg/mL, respectively. It was possible to predict the PTX concentration even when polyoxyethylene castor oil and anhydrous ethanol were added, as in the commercially available PTX formulation, by diluting 32-fold with saline after mixing. Our findings show that PTX can be more accurately quantified using a calibration curve when prepared in a methanol/water mixture without the need for special devices or techniques.

Detection of honey adulteration with starch syrup by high performance liquid chromatography

According to saccharide profile comparison between starch syrups and pure honeys analysed through high performance liquid chromatography (HPLC), a characteristic peak was found at 15.25min retention time in HPLC chromatogram of syrup, but no peak was observed at the same retention time in chromatogram of pure honeys. This characteristic peak for syrup was identified as an overlapping peak of oligosaccharides with more than 5 degree of polymerisation (DP) based on HPLC chromatogram comparison between starch syrup and a series of standard mono-, di- and oligosaccharides of 3–7 DP. Additionally syrup content correlated linearly with the height of the characteristic peak of syrup under different slope in two ranges 2.5–7.5% and 10–100%, respectively. Therefore, the characteristic peak at 15.25min retention time can serve as a syrup indicator in HPLC analysis of the adulterated honeys. This new HPLC method for honey adulteration detection was further applied in an authenticity inspection on more than 100 commercial honeys. In addition to the improved accuracy of honey adulteration detection, the proposed HPLC method was simple, low cost and easy practice for honey product quality control by government department considering the popularity of HPLC device and technology.

TCH-006 Development and Validation of 3 Methods – UV Spectrophotometry, Flow Injection Analysis and Liquid Chromatography – For the Control of Nystatin Capsules.

BackgroundAs an alternative to amphotericin B used for selective digestive decontamination, physicians asked the Hospital Pharmacy for the preparation of nystatin capsules, 500,000 IU.PurposeThree methods were considered for routine checking:...

Implementing Neonatal Screening for Haemoglobinopathies in the Netherlands

The birth prevalence of severe haemoglobinopathies such as sickle cell disease (SCD) in the Netherlands has been estimated to be at least 50 newborns per year. Neonatal screening for SCD was added to the Dutch screening programme in January 2007. We here evaluated three high performance liquid chromatography (HPLC) systems for application in neonatal screening for haemoglobinopathies, and present the results of a subsequent pilot screening programme. The Variant NewBorn Screening (Vnbs) HPLC system (Bio-Rad) was validated by analysing 131 blood samples and blood mixtures. Subsequently, the performance of the G7 (Tosoh BioScience) and Ultra (Primus Corporation) was compared with the Vnbs. The three HPLC analysers were tested in a pilot screening programme on 21,969 dried blood spot samples from the routine Dutch neonatal screening programme. The pilot screening resulted in 188 abnormal patterns. The three HPLC devices presented comparable within- and between-run precision and detected the abnormal samples similarly. The high throughput, sampling systems, presentation of results, and integration of the chromatograms, however, were different. All three analysers detected the same abnormal haemoglobins satisfactorily, but integrated the chromatograms with variable imprecision. Comparison of the results suggested that the Bio-Rad Vnbs was the preferred system. However, software adjustments were required to improve the diagnostic potential of this device for screening for beta- and alpha-thalassaemia.

分離分析の基礎―ＨＰＬＣを中心に―

High-performance liquid chromatography (HPLC) is one of the most useful methods for both qualitative and quantitative analysis of individual compounds that may be present in a sample. Researchers can select an appropriate method in various combinations of stationary phases with mobile phases depending on an objective compound and other matrix in a sample. This review aims to provide the outline of separation analysis and HPLC, including the history of chromatography, HPLC device configuration, typical separation modes, i.e., reversed-phase, normal-phase, ion-exchanged, ion-pair reverse-phase, and size exclusion HPLC, typical methods for amino acid analysis, key parameters of chromatography performance, typical procedure for optimum separation condition, usefulness of column downsizing, and method robustness, to the beginners of HPLC operations.

Macrovascular risk and diagnostic criteria for type 2 diabetes: implications for the use of FPG and HbA(1c) for cost-effective screening.

The use of fasting plasma glucose (FPG) level > or =7.0 mmol/l leads to underdiagnosis of type 2 diabetes compared with the oral glucose tolerance test (OGTT). The OGTT is of limited use for population screening. Most of the increase in cardiovascular risk in relation to increasing blood glucose occurs before the threshold at which the diagnosis of type 2 diabetes is made. The aim of this study was to evaluate the use of HbA(1c) and FPG as predictors of type 2 diabetes and cardiovascular risk and, accordingly, to develop a rational approach to screening for abnormalities of glucose tolerance. OGTT and measurement of HbA(1c) and FPG levels were performed in 505 subjects screened for type 2 diabetes. Anthropomorphic measurements were obtained. A cardiovascular risk factor questionnaire was completed. The subjects were aged 19-88 years (mean 53.8). The incidence of type 2 diabetes was 10.4% based on the OGTT and 4% based on an FPG level > or =7.0 mmol/l. Using high-performance liquid chromatography (HPLC), HbA(1c) of <4.7 and > or =6.2% predicted with certainty the absence or presence of type 2 diabetes as defined by the OGTT. The corresponding cutoffs were <5.0 and > or =6.8% for HbA(1c) (DCA2000 HPLC device; Bayer Diagnostics, Mulgrave, Australia) and <4.7 and > or =6.4 mmol/l for FPG. However, 75-85% of subjects in each case had intermediate values, which were therefore nondiagnostic. Cardiovascular risk increased at least 2.2 times at an HbA(1c) level > or =6.2% (by HPLC), 1.8-2.2 times at an HbA(1c) level of 5.6-6.1% (by HPLC), 2 times at an FPG level > or =6.4 mmol/l, and 1.7-1.9 times at an FPG level of 5.6-6.3 mmol/l. Measurement of FPG and HbA(1c) levels will diagnose or exclude type 2 diabetes with certainty in a minority (15%) of people. There is a continuous relationship between FPG and HbA(1c) and cardiovascular risk. Accordingly, we propose that there is a rational basis for using either FPG and HbA(1c) for purposes of screening and assigning risk. Individuals with an HbA(1c) level of 5.6-6.1% and an FPG level of 5.6-6.3 mmol/l are at greatest risk for cardiovascular disease and should be targeted for further evaluation. An algorithm outlining a cost-effective approach is presented.