scholarly journals Determination of Available Lysine by Planar Chromatography: A Useful Tool for Protein Quality Evaluation in Fish Feed

2009 ◽  
Vol 92 (3) ◽  
pp. 699-702 ◽  
Author(s):  
Mario Vega ◽  
Mario Aranda
Keyword(s):  
Quality Control ◽  
High Throughput ◽  
Protein Quality ◽  
Low Cost ◽  
Fish Feed ◽  
Planar Chromatography ◽  
Intermediate Precision ◽  
Relative Standard ◽  
Available Lysine

Abstract Due to the essentiality of lysine for fish, its availability is commonly used as a predictor of the protein nutritional quality of fish feed. The objective of this work was to establish a high-throughput analytical method for protein quality control in fish feed through the measurement of available lysine by planar chromatography. Sample was first incubated with 1-fluoro-2,4-dinitrobenzene to obtain the dinitrophenyl-lysine derivative and then hydrolyzed with hydrochloric acid in order to release the derivative from proteins. Chromatography was performed on silica gel 60 F254 HPTLC plates using n-propanol25 ammonia (7 + 3, v/v) as mobile phase. Quantitative analysis was performed by densitometry in the absorbance mode at 360 nm. Calibration showed a polynomial relationship with an R2 of 0.9991 in the range of 25 to 125.0 ng/band. Repeatability relative standard deviation (RSD) and intermediate precision (RSD) in matrix were 0.8 and 3.6, respectively. Recoveries of spiked samples at two levels ranged from 72 to 85 with RSD from 3 to 8. This method provides the salmon feed industry with a reliable, high-throughput, and low-cost means for routine quality control of available lysine.

scholarly journals A simple method for the quantification of diclofenac potassium in oral suspension by high-performance liquid chromatography with UV-detection

2013 ◽  
Vol 49 (3) ◽  
pp. 589-597 ◽  
Author(s):  
Alexandre Machado Rubim ◽  
Jaqueline Bandeira Rubenick ◽  
Luciane Varine Laporta ◽  
Clarice Madalena Bueno Rolim
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Oral Suspension ◽  
Reverse Phase ◽  
Intermediate Precision ◽  
Simple Method ◽  
Ultraviolet Detection ◽  
Relative Standard ◽  
Validation Parameters

A rapid, simple and low cost method was developed to determine diclofenac potassium (DP) in oral suspension, using a reverse-phase column (C8, 150 mm x 4.6 mm, 5 µm), mobile phase containing methanol/buffer phosphate (70:30 v/v, pH 2.5), at a flow rate of 1.0 mL/min, isocratic method, and ultraviolet detection at 275 nm. A linear response (r = 1.0000) was observed in the range of 10.0-50.0 µg/mL. Validation parameters such as linearity, specificity, precision, accuracy and robustness were evaluated. The method presented precision (repeatability: relative standard deviation = 1.21% and intermediate precision: between-analyst = 0.85%). The specificity of the assay was evaluated by exposure of diclofenac potassium under conditions of stress such as hydrolysis, photolysis, oxidation and high temperature. The method presented accuracy values between 98.28% and 101.95%. The results demonstrate the validity of the proposed method that allows determination of diclofenac potassium in oral suspension and may be used as an alternative method for routine analysis of this product in quality control.

scholarly journals Spectrofluorometric determination of L-tryptophan in canary (Canarium indicum L.) seed protein hydrolysate

2019 ◽  
Vol 10 (1) ◽  
pp. 4780-4785
Keyword(s):  
Protein Hydrolysate ◽  
Intermediate Precision ◽  
North Sulawesi ◽  
Accuracy Test ◽  
Spectrofluorometric Determination ◽  
Relative Standard ◽  
Indigenous Plant ◽  
Assay Precision ◽  
Specific Reagent

Canary (Canarium indicum L.) is an indigenous plant of Indonesia, which mainly grows in the eastern part of Indonesia, especially in the Maluku, North Sulawesi, and Seram islands. We believe that no scientific reports have been conducted about L-tryptophan content in Canarium indicum. Therefore, this study was conducted to determine the presence and quantitate the aromatic amino acid (L-tryptophan) in the canary protein hydrolysate by the spectrofluorometric method. The protein hydrolysate was prepared by two hydrolysis methods, enzymatic and alkaline hydrolysis. L-tryptophan can be differentiated from tyrosine directly without using any reagent by excitation of the sample at 295 nm in order to avoid tyrosine emission. The equation of calibration curve correlation using standard in the range 0.5-5 ppm was y = 6632.3x - 845.42 and correlation coefficient of 0.9997, while the coefficient of variance in linear regression was 1.29%. The detection limit and quantification limit obtained were 0.116 ppm and 0.35 ppm respectively. The recoveries of the accuracy test were obtained in the range of 95-96%. The relative standard deviation of intra-assay precision tests were obtained in the range of 0.5-1.8%, while the intermediate precision in the range of 2.18-3.74%. L-tryptophan was detected in all samples (papain, pepsin, and alkaline hydrolysate), with concentrations 5.6, 5 and 1.53 mg/100mg of protein respectively. The used fluorometric method complied with the validation requirements and can be used to analyze L-tryptophan in samples containing tyrosine without overlapping of spectra and without the use of any specific reagent.

scholarly journals Direct Determination of Free Methionine in Soy-Based Infant Formula

2004 ◽  
Vol 87 (1) ◽  
pp. 123-128
Author(s):  
Paul Johns ◽  
Rosalyn Phillips ◽  
Lobat Dowlat
Keyword(s):  
Infant Formula ◽  
Mobile Phase ◽  
Method Comparison ◽  
Water System ◽  
Direct Determination ◽  
Reversed Phase ◽  
Intermediate Precision ◽  
Relative Standard ◽  
Limit Of Quantitation

Abstract A method was developed for the direct determination of free methionine in soy-based infant formula, with analyte separation and quantitation by reversed-phase liquid chromatography (LC), and UV absorbance at 214 nm, respectively. Sample preparation required only dilution with mobile phase and syringe filtration. Using a 0.02M KH 2 PO 4 mobile phase (pH adjusted to 2.9 with 85% o-phosphoric acid) and 0.7 mL/min flow rate, methionine eluted at approximately 8 min, and total run time was 14 min after column regeneration with acetonitrile–water. System linearity was demonstrated as peak area versus analyte concentration, ranging from 80 to 120% of the formula specification for free methionine (r > 0.999, and all residuals <0.45%). Intermediate precision relative standard deviation values were <1.5% for ready-to-feed and reconstituted powder samples, and recoveries ranged from 98.0 to 103.5% for inter-method comparison with an amino acid analyzer method. The limit of quantitation was 3 mg methionine/L in the “as fed” infant formula. Despite the relatively weak UV absorptivity of methionine, the 214 nm signal was sufficiently intense in the 30–65 mg/L (201–436 μM) range to afford quantitation by peak area proportionation versus a 2-point external standard calibration. This direct UV detection after reversed-phase LC separation provides a simple and accurate method for determining free methionine without derivatization.

Determination of Nitrogen Content in Milk by the Kjeldahl Method Using Copper Sulfate: Interlaboratory Study

1988 ◽  
Vol 71 (5) ◽  
pp. 893-898 ◽  
Author(s):  
R Grappin ◽  
William Horwitz
Keyword(s):  
Quality Control ◽  
Nitrogen Content ◽  
Copper Sulfate ◽  
Interlaboratory Study ◽  
Internal Quality ◽  
Relative Standard ◽  
Nitrogen Concentrations ◽  
Kjeldahl Method ◽  
Repeatability And Reproducibility

Abstract Copper sulfate was substituted for mercury as the catalyst in the International Dairy Federation (IDF) Standard 20A:1986 method for the determination of nitrogen content in milk. The substitution was supported by results obtained in an interlaboratory study by 24 laboratories in 12 countries. Each laboratory analyzed 12 test samples of milk as blind duplicates in a double split level design with high, medium, and low nitrogen concentrations. The method protocol requires the concurrent analyses of an ammonium salt solution and a tryptophan solution as internal quality control standards with a minimum nitrogen recovery between 99 and 100% for the former and at least 98% for the latter. The repeatability and reproducibility relative standard deviations are 0.5 and 1%, respectively, for the range 0.35-0.70 g N/100 g. The performance of the laboratories that did not meet the required quality control specifications was clearly poorer than that of those that did meet the specifications.

A Validated Method for the Quality Control of Andrographis paniculata Preparations

Planta Medica ◽  
2017 ◽  
Vol 83 (14/15) ◽  
pp. 1207-1213 ◽  
Author(s):  
Anastasia Karioti ◽  
Patricia Timoteo ◽  
Maria Bergonzi ◽  
Anna Bilia
Keyword(s):  
Quality Control ◽  
Time Course ◽  
Symptomatic Treatment ◽  
Reversed Phase ◽  
Andrographis Paniculata ◽  
Gradient System ◽  
Solvent Mixtures ◽  
Relative Standard ◽  
Precision And Accuracy

Abstract Andrographis paniculata is a herbal drug of Asian traditional medicine largely employed for the treatment of several diseases. Recently, it has been introduced in Europe for the prophylactic and symptomatic treatment of common cold and as an ingredient of dietary supplements. The active principles are diterpenes with andrographolide as the main representative. In the present study, an analytical protocol was developed for the determination of the main constituents in the herb and preparations of A. paniculata. Three different extraction protocols (methanol extraction using a modified Soxhlet procedure, maceration under ultrasonication, and decoction) were tested. Ultrasonication achieved the highest content of analytes. HPLC conditions were optimized in terms of solvent mixtures, time course, and temperature. A reversed phase C18 column eluted with a gradient system consisting of acetonitrile and acidified water and including an isocratic step at 30 °C was used. The HPLC method was validated for linearity, limits of quantitation and detection, repeatability, precision, and accuracy. The overall method was validated for precision and accuracy over at least three different concentration levels. Relative standard deviation was less than 1.13%, whereas recovery was between 95.50% and 97.19%. The method also proved to be suitable for the determination of a large number of commercial samples and was proposed to the European Pharmacopoeia for the quality control of Andrographidis herba.

Cloud Point Extraction and Spectrophotometry Determination of Lead in Environment Water Using 5-Br-PADAP

2013 ◽  
Vol 830 ◽  
pp. 345-348
Author(s):  
Lin Gao ◽  
Sheng Jie Chen ◽  
Fang Chen ◽  
Wen Hong Zhou ◽  
Jun Long Yao
Keyword(s):  
Cloud Point ◽  
Cloud Point Extraction ◽  
Detection Method ◽  
Low Cost ◽  
Calibration Graph ◽  
Buffer Solution ◽  
Relative Standard ◽  
Triton X ◽  
Optimized Conditions

A simple, sensitive, green and low cost detection method based on the cloud point extraction (CPE) separation and spectrophotometry was proposed for the determination of lead. In pH=9.0 H3BO3 buffer solution, Pb(II) reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) in the presence of Triton X-100 yielding a hydrophobic complex, which then is extracted into micro-volume surfactant-rich phase. The calibration graph was linear in the range of 20-400 µg/L (at 560 nm). Under the optimized conditions, the detection limits of 10.94 µg/L and the relative standard deviations(RSD) of 2.0% (n=5) for Lead(II) were found, respectively. The sensitivity and absorbance of this method are at least five times higher when compared with that of usual 5-Br-PADAP spectrophotometry without CPE, and the proposed method has been applied to the determination of Lead in environment water samples with satisfactory results.

scholarly journals Determination of Methyldopa and Paracetamol in Pharmaceutical Samples by a Low Cost Genipa americana L. Polyphenol Oxidase Based Biosensor

2019 ◽  
Vol 9 (3) ◽  
pp. 416-422
Author(s):  
Rafael Souza Antunes ◽  
Douglas Vieira Thomaz ◽  
Luane Ferreira Garcia ◽  
Eric de Souza Gil ◽  
Vernon Sydwill Sommerset ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Low Cost ◽  
Differential Pulse ◽  
Pharmaceutical Samples ◽  
Polyphenol Oxidases ◽  
Voltammetric Techniques ◽  
Relative Standard ◽  
Pulse Voltammetry ◽  
Phenolic Drugs

Purpose: Jenipapo fruit (Genipa americana L) is a natural source of polyphenol oxidases (PPOs) whose potential in pharmaceutical analysis is noteworthy. Henceforth, this work reports the electrochemical study of a low-cost PPO-based biosensor produced from the crude extract of Jenipapo fruits and accounts a practical approach to employ this biosensor in the determination of methyldopa and paracetamol in pharmaceutical samples. Methods: In order to investigate the electrochemical properties of the biosensor, theoretical and practical approaches were employed, and both samples and the biosensor were analyzed through electrochemical impedance spectroscopy (EIS) and voltammetric techniques, namely: differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Results: showcased that the biosensor presented good analytical features, as well as low detection limits (8 μmol L-1 for methyldopa and 5 μmol L-1 for paracetamol). The relative standard deviation was less than 5% mid-assay. Conclusion: The use of this biosensor is a reliable, low cost and useful alternative in the pharmaceutic determination of phenolic drugs (e.g. methyldopa and paracetamol).

scholarly journals Simultaneous Quantification of Two Flavonoids in Morus alba by High Performance Liquid Chromatography Coupled with Photodiode Array Detector

2018 ◽  
Vol 13 (11) ◽  
pp. 1934578X1801301
Author(s):  
Chang-Seob Seo ◽  
Hyeun-Kyoo Shin
Keyword(s):  
Quality Control ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Morus Alba ◽  
Array Detector ◽  
Root Bark ◽  
Relative Standard ◽  
Photodiode Array

The root bark of Morus alba L. (Family: Moraceae) is an important medicinal herb in many countries and has long been used as a traditional medicine for the treatment of cough, fever, blood pressure reduction, and respiratory diseases. In the present study, the simultaneous determination of two flavonoids, kuwanon G and morusin, for quality control of M alba was conducted using high-performance liquid chromatography (HPLC) equipped with photodiode array (PDA) detector. The column used for separation of kuwanon G and morusin was a Gemini C18 analytical column maintained at 45°C. The mobile phase for efficient separation of two analytes was flowed 0.1% (v/v) aqueous formic acid-acetonitrile with gradient elution. The detection wavelength for quantification was set at 266 nm. The optimized method showed good linearity with coefficients of determination of 0.9998 within the tested concentration ranges. The limits of detection for the two flavonoids, kuwanon G and morusin, were 0.69 μg/mL and 0.35 μg/mL and the limits of quantification of kuwanon G and morusin, were 2.10 μ/mL and 1.07 μg/mL. The recoveries were 98.40–111.55% and the relative standard deviation (RSD) value was within 3.50%. The RSD values of intra- a g d interday precisions were 0.08–0.70% and 0.06-0.48%, respectively. The amounts of kuwanon G and morusin were 1.94-2.26 mg/g and 1.05–1.12 mg/g. The established HPLC-PDA method will help to improve the quality control of M. alba and related products.

Flow injection spectrophotometric determination of iron(III) using diphenylamine-4-sulfonic acid sodium salt

2008 ◽  
Vol 62 (4) ◽  
Author(s):  
Adem Asan ◽  
Muberra Andac ◽  
Ibrahim Isildak ◽  
Nihat Tinkilic
Keyword(s):  
Flow Injection ◽  
Sodium Salt ◽  
Sulfonic Acid ◽  
Low Cost ◽  
Standard Addition ◽  
Acid Sodium Salt ◽  
Highly Sensitive ◽  
Relative Standard ◽  
Sulfonic Acid Sodium Salt

AbstractA highly sensitive and very simple spectrophotometric flow-injection analysis (FIA) method for the determination of iron(III) at low concentration levels is presented. The method is based on the measurement of absorbance intensity of the red complex at 410 nm formed by iron(III) and diphenylamine-4-sulfonic acid sodium salt (DPA-4-SA). It is a simple, highly sensitive, fast, and low cost alternative method using the color developing reagent DPA-4-SA in acetate buffer at pH 5.50 and the flow-rate of 1 mL min−1 with the sample throughput of 60 h−1. The method provided a linear determination range between 5 μg L−1 and 200 μg L−1 with the detection limit (3S) of 1 μg L−1 of iron(III) using the injection volume of 20 μL. FIA variables influencing the system performance were optimized. The amount of iron(III) and total iron in river and seawater samples was successfully determined. Repeatability of the measurements was satisfactory at the relative standard deviation of 3.5 % for 5 determinations of 10 μg L−1 iron(III). The accuracy of the method was evaluated using the standard addition method and checked by the analysis of the certified material Std Zn/Al/Cu 43 XZ3F.

scholarly journals A fully validated microbiological assay to evaluate the potency of ceftriaxone sodium

2013 ◽  
Vol 49 (4) ◽  
pp. 753-762 ◽  
Author(s):  
Maria Luisa Manfio ◽  
Danielle Araújo Agarrayua ◽  
Jaison Carlosso Machado ◽  
Cleber Alberto Schmidt
Keyword(s):  
Low Cost ◽  
Pharmaceutical Formulations ◽  
Microbiological Assay ◽  
Intermediate Precision ◽  
Chromatography Method ◽  
Beta Lactamases ◽  
Pharmaceutical Samples ◽  
Ceftriaxone Sodium ◽  
Relative Standard ◽  
Liquid Chromatography Method

Ceftriaxone (CFTX) sodium is a third-generation, broad-spectrum cephalosporin that is resistant to beta-lactamases. An alternative bioassay for the assessment of the potency of this drug in pharmaceutical formulations has not been previously reported. Thus, this paper reports the development and full validation of a 3 x 3 agar diffusion bioassay using a cylinder-plate method to quantify CFTX sodium in pharmaceutical samples. The strain Staphylococcus aureus ATCC 6538P was used as the test microorganism, and the results of the proposed bioassay displayed high linearity, precision, accuracy, specificity and robustness. All potency results were statistically analyzed using an analysis of variance (ANOVA) and were found to be linear (r=0.99999) in the range of 16-64 µg/mL, accurate (100.5%), and precise [repeatability: relative standard deviation (RSD)=1.4%; intermediate precision: between-day RSD=2.1% and between-analyst RSD=2.5%]. The specificity of the bioassay was determined by evaluating a degraded sample (50 ºC) at 0, 24 and 48 hours as compared against the results from the pharmacopeial liquid chromatography method for CFTX. The results validated the proposed microbiological assay, which allows reliable quantitation of CFTX in pharmaceutical samples. Moreover, it is a useful, simple and low-cost alternative method for monitoring the quality of this medicine.

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