scholarly journals Determination of the Detection Limit of the Detection of GMO in Food Using the Isothermal Solid-Phase Recombinase Polymerase Amplification on Microfluidic DVDs

2021 ◽  
Vol 3 (2) ◽  
pp. 17-19
Author(s):  
Noor Azlina Masdor
Keyword(s):  
Standard Deviation ◽  
Detection Limit ◽  
Calibration Curve ◽  
Genetically Modified Organisms ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Major Drawback ◽  
Fast Screening ◽  
Simple Detection

A major drawback of the current literature on bioassay development is that these tests are not made using statistically robust methods for establishing the limit of detection. As an alternative, researchers often make use of simple detection-limit methods that are only roughly indicative of the actual detection limit. We can only assume that this is due to a practical need for simplified processes, in addition to the notion that the limit of detection theory has already been lowered to practice for bioassays. A DNA sensor based on light intensity of the scanning laser on a DVD drive with microfluidic layer etched onto the polycarbonate surface of an ordinary DVD has been previously developed for fast screening of genetically modified organisms (GMOs). The resultant calibration curve showed a sigmoidal calibration curve but was not modelled according to any of the sigmoidal models available. The objective of this study is the remodel the data using the standard 4-PL model and to determine the Limits of Detection (LOD) based on the standard method. The LOD value obtained through the 4PL modelling exercise based on a pooled standard deviation method yielded an LOD value of 62 mg/g (95% confidence interval of 17 to 158), which was quite similar to the classical three standard deviation of the blank method but was lower than the rough estimation employed in the original publication.

scholarly journals Determination of Sodium Cromoglycate by a New Kinetic Spectrophotometric Method in Biological Samples

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Mohsen Keyvanfard ◽  
Khadijeh Alizad ◽  
Razieh Shakeri
Keyword(s):  
Standard Deviation ◽  
Sodium Cromoglycate ◽  
Spectrophotometric Method ◽  
Calibration Curve ◽  
Biological Samples ◽  
Limit Of Detection ◽  
Micellar Medium ◽  
Relative Standard ◽  
Kinetic Spectrophotometric

A new kinetic spectrophotometric method is described for the determination of ultratrace amounts of sodium cromoglycate (SCG). The method based on catalytic action of SCG on the oxidation of amaranth with periodate in acidic and micellar medium. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of the amaranth at 518 nm, for the first 4 min from initiation of the reaction. Calibration curve was linear in the range of 4.0−36.0 ng mL−1SCG. The limit of detection is 2.7 ng mL−1SCG. The relative standard deviation (RSD) for ten replicate analyses of 12, 20, and 28 ng mL−1SCG was 0.40%, 0.32%, and 0.53%, respectively. The proposed method was used for the determination of SCG in biological samples.

scholarly journals Flotation-Spectrophotometric Method for the Determination of Aluminium ion Using Xylenol Orange

2011 ◽  
Vol 8 (4) ◽  
pp. 1528-1535 ◽  
Author(s):  
F. Nekouei ◽  
Sh. Nekouei
Keyword(s):  
Standard Deviation ◽  
Spectrophotometric Method ◽  
Calibration Curve ◽  
Limit Of Detection ◽  
Xylenol Orange ◽  
Molar Absorptivity ◽  
Relative Standard ◽  
Ion Associate ◽  
Sensitive Method

A simple, fast, reproducible and sensitive method for the flotation- spectrophotometric determination of Al3+is reported. The apparent molar absorptivity (ε) of the ion associate was determined to be 8.35×104L mol-1cm-1. The calibration curve was linear in the concentration range of 1.0-50 ng mL-1of Al3+with a correlation coefficient of 0.9997. The limit of detection (LOD) was 0.621 ng mL. The relative standard deviation (RSD) at 10 and 30 ng mL-1of aluminium were 1.580 and 2.410% (n=7) respectively. The method was applied for measuring the amount of aluminium in water samples.

scholarly journals MEAN CENTERING OF RATIO SPECTRA METHOD FOR THE ANALYSIS OF THEOPHYLLINE AND EPHEDRINE HCL MIXTURE IN TABLET

2018 ◽  
Vol 11 (5) ◽  
pp. 218
Author(s):  
Muchlisyam Muchlisyam ◽  
Sudarmi Sudarmi ◽  
Cindy Caroline
Keyword(s):  
Standard Deviation ◽  
Detection Limit ◽  
Spectrophotometric Method ◽  
Limit Of Detection ◽  
Standard Addition ◽  
Addition Method ◽  
Limit Of Quantification ◽  
Mean Centering ◽  
Relative Standard

 Objective: Mean centering of ratio spectra method (MCR method) is one of the simplest methods for the determination of drug mixtures. The purpose of this research is to determine the content of theophylline (THEO) and ephedrine HCl (EPH) in tablets by MCR spectra method.Methods: This research was conducted with the MCR method. It was measured at 271 nm for THEO and 257 nm for EPH using 0.1 N HCL as a solution. The calculation was conducted with Matlab application. The analytical characteristics of the method are detection limit, accuracy, precision, and selectivity. Standard addition method was used to increase the concentration of EPH in the sample until it reached the range of calibration concentration.Result: The research has showed that validations for THEO were 100.57% for accuracy, 0.68% for relative standard deviation (RSD), 0.46 μg/mL for limit of detection (LOD), and 1.52 μg/mL for limit of quantification (LOQ). Meanwhile, the validations for EPH are 100.02% for accuracy, 0.07% for RSD, 43.12 μg/mL for LOD, and 143.72 μg/mL for LOQ. The level of THEO is 97.43 ± 0.17% and the level of EPH is 101.36 ± 0.25% for brand one’s tablet. Meanwhile, brand two’s tablet contains 98.72 ± 0.14% of THEO and 103.62 ± 0.23% of EPH.Conclusion: MCR ultraviolet spectrophotometric method can be used to determine the content of THEO and EPH in tablets and meets the detection limit, accuracy, precision, and selectivity.

scholarly journals An Immunoenzymatic Method for the Determination of Ochratoxin A in Biological Liquids (Colostrum and Cow’s Milk)

Toxins ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 673
Author(s):  
Magdalena Cuciureanu ◽  
Cristina Tuchiluș ◽  
Anca Vartolomei ◽  
Bogdan Ionel Tamba ◽  
Lorena Filip
Keyword(s):  
Detection Limit ◽  
Ochratoxin A ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Biological Fluids ◽  
Cow’S Milk ◽  
Limit Of Quantification ◽  
Cow's Milk ◽  
Low Concentrations

Ochratoxins are mycotoxins that have been extensively studied lately due to the multiple toxic effects such as nephrotoxicity, hepatotoxicity, and carcinogenicity. These toxins contaminate plant and animal foods and after ingestion they reach into body fluids. The method of competitive direct enzyme immunoassay, in the solid phase, was validated through the determination of specific parameters (performance, linearity, recovery percentage, limit of detection, limit of quantification). The validated method was used to determine ochratoxin A in colostrum and cow’s milk. The method applied for the determination of ochratoxin A was linear for the concentration range of 0.0–0.5 ng/mL, the value for the regression coefficient (r) was 0.9838. Ochratoxin A was present in 91.67% of the colostrum and in 93.33% of cow’s milk samples. The linearity of the method, demonstrated for very low concentrations of analyte, the detection limit as well as the limit of quantification recommend the method for the determinations of micro-pollutants from foods, including biological fluids.

scholarly journals Perbandingan Pengukuran Kadar Vitamin C Menggunakan Spektrofotometri UV-Vis pada Panjang Gelombang UV dan Visible

2019 ◽  
Vol 1 (2) ◽  
pp. 77-81
Author(s):  
Khoirul Ngibad ◽  
Dheasy Herawati
Keyword(s):  
Free Radical ◽  
Detection Limit ◽  
Vitamin C ◽  
Calibration Curve ◽  
Oxidation Reaction ◽  
Limit Of Detection ◽  
The Other ◽  
Visible Wavelength ◽  
Food And Beverage

Vitamin C is a source of antioxidants which has a primary function to inhibit the occurrence of an oxidation reaction and inhibit a free radical. The source of vitamin C can be found in food and beverage. This study aims to compare the measurement of vitamin C levels using a UV-Vis spectrophotometer at UV and Visible wavelength. The method used in this study was the UV-Vis spectrophotometry method. The analysis of vitamin C levels at UV wavelength 266 nm and Visible wavelength 494 nm with a calibration curve range 0.3 to 0.8 mg/L. Validation of the methods studied included: linearity, detection limits, quantization limits, and precision. The results showed that the measurement of vitamin C levels at UV wavelengths resulted in the linearity of concentrations of 0.2 - 0.8 mg / L, the limit of detection of 0.05 mg/L, the limit of quantization of 0.17 mg/L and level of precision with RSD to 0.2015. On the other hand, the measurement of vitamin C levels in the Visible wavelength produced linearity from concentrations of 0.3 to 0.8 mg/L, the detection limit of 0.05 mg/L, quantization limit of 0.18 mg/L and the level of precision with RSD of 1.0489. Thus, the determination of vitamin C levels in samples using a UV-Vis spectrophotometer was preferred to be measured at UV wavelengths.

scholarly journals Determination of Bentazone in Waters by Solid-Phase Spectrofluorimetry

1996 ◽  
Vol 79 (2) ◽  
pp. 567-570 ◽  
Author(s):  
José Luis Vilchez ◽  
Diego Torres-Bustos ◽  
Rosario Blanc ◽  
Alberto Navalón
Keyword(s):  
Standard Deviation ◽  
Detection Limit ◽  
Relative Standard Deviation ◽  
Natural Water ◽  
Water Samples ◽  
Solid Phase ◽  
Excitation Wavelength ◽  
Relative Standard ◽  
Sensitive Method

Abstract A sensitive method for determining trace amounts of bentazone was developed. The method is based on solid-phase spectrofluorimetry. Bentazone was fixed on a dextran-type anion-exchange gel, and the fluorescence of the gel, packed in a 1 mm thick quartz cell, was measured directly at an excitation wavelength of 338 nm and an emission wavelength of 436 nm by using a solid-phase attachment. The applicable concentration range was 2.0–120.0 μg/L, with a detection limit of 0.4 μg/L. The relative standard deviation at the 30.0 μg/L level was 1.2%. The method was used to determine bentazone in natural water samples. Recoveries were 96.0–102.5%.

scholarly journals Determination of 77 Multiclass Pesticides and Their Metabolitesin Capsicum and Tomato Using GC-MS/MS and LC-MS/MS

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1837
Author(s):  
Harischandra Naik Rathod ◽  
Bheemanna Mallappa ◽  
Pallavi Malenahalli Sidramappa ◽  
Chandra Sekhara Reddy Vennapusa ◽  
Pavankumar Kamin ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Solid Phase ◽  
Graphitized Carbon Black ◽  
Limit Of Quantification ◽  
Gas And Liquid Chromatography ◽  
Relative Standard ◽  
The Matrix ◽  
Liquid Chromatography Tandem Mass ◽  
Primary Secondary Amine

A quick, sensitive, and reproducible analytical method for the determination of 77 multiclass pesticides and their metabolites in Capsicum and tomato by gas and liquid chromatography tandem mass spectrometry was standardized and validated. The limit of detection of 0.19 to 10.91 and limit of quantification of 0.63 to 36.34 µg·kg−1 for Capsicum and 0.10 to 9.55 µg·kg−1 (LOD) and 0.35 to 33.43 µg·kg−1 (LOQ) for tomato. The method involves extraction of sample with acetonitrile, purification by dispersive solid phase extraction using primary secondary amine and graphitized carbon black. The recoveries of all pesticides were in the range of 75 to 110% with a relative standard deviation of less than 20%. Similarly, the method precision was evaluated interms of repeatability (RSDr) and reproducibility (RSDwR) by spiking of mixed pesticides standards at 100 µg·kg−1 recorded anRSD of less than 20%. The matrix effect was acceptable and no significant variation was observed in both the matrices except for few pesticides. The estimated measurement uncertainty found acceptable for all the pesticides. This method found suitable for analysis of vegetable samples drawn from market and farm gates.

Determination of Bendiocarb Insecticide by Reverse Flow Injection Analysis Using a Solid-Phase Reactor Containing Micro PbO2, Nano PbO2 and Grafted SiO2 - PbO2 Immobilized

2020 ◽  
Vol 42 (1) ◽  
pp. 31-31
Author(s):  
Malik H Alaloosh Alamri Malik H Alaloosh Alamri ◽  
Sadeem Subhi Abed and Abdulkareem M A Alsammarraie Sadeem Subhi Abed and Abdulkareem M A Alsammarraie
Keyword(s):  
Flow Injection ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Reverse Flow ◽  
Blue Color ◽  
Wide Range ◽  
Solid Phase Reactor ◽  
Grafted Nanoparticles ◽  
Reverse Flow Injection

Bendiocarb (BEN) is an acutely toxic carbamate insecticide which used in public places and agriculture, it is also effective against a wide range of nuisance and disease vector insects. A new rapid and sensitive reverse flow injection spectrophotometric procedure coupled with on-line solid-phase reactor is designed in this article for the determination of BEN in its insecticidal formulations and water samples, by using three different solid-phase reactors containing bulk PbO2 (B-SPR), PbO2 nanoparticles (N-SPR) and grafted nanoparticles of SiO2-PbO2 (G-SPR) immobilized on cellulose acetate matrix (CA). This method of oxidative coupling is based on alkaline hydrolysis of the BEN pesticide, and then coupled with N,N dimethyl-p-phenylenediamine sulphate (DMPD) to give a blue color product which measured at λmax 675 nm. It worth to mentioned that under optimal conditions, Beer’s law is obeyed in the range of 1-175 μg mL-1 for B-SPR and 0.25-70 μg mL-1 of BEN for both N-SPR and G-SPR respectively within limit of detection (LOD) of 0.931, 0.234 and 0.210 μg mL-1 for B-SPR N-SPR and G-SPR respectively. The surface methodology of the solid phase was also investigated by using atomic force microscopy.

scholarly journals Oxytetracycline Residues in Honey Analyzed by Liquid Chromatography with UV Detection

2013 ◽  
Vol 57 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Anna Gajda ◽  
Andrzej Posyniak ◽  
Andrzej Bober ◽  
Tomasz Błądek ◽  
Jan Żmudzki
Keyword(s):  
Liquid Chromatography ◽  
Oxalic Acid ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Experimental Treatment ◽  
Uv Detection ◽  
Limit Of Quantification ◽  
Chromatography Method ◽  
Liquid Chromatography Method

Summary A liquid chromatography method with UV detection for determination of oxytetracycline (OTC) in honey has been developed. The samples were extracted with the solution of oxalic acid. The clean-up procedure was performed by solid phase extraction (SPE) using polymeric Strata X and carboxylic acid cartridges. Chromatographic separation was carried out on the Luna C8 analytical column with mobile phase consisting of acetonitrile-0.02 M oxalic acid. The method has been successfully validated according to the requirements of the European Decision 2002/657/EC and this method is used in routine control of oxytetracycline in honey samples. The limit of detection (LOD) and limit of quantification (LOQ) of the presented method were 10 and 12.5 μg/kg, respectively. The developed method has also been verified in quantitative determination of oxytetracycline residues in honey after experimental treatment with this product in bee colonies.

Direct solid-phase enzymoimmunoassay of testosterone in saliva.

1989 ◽  
Vol 35 (10) ◽  
pp. 2044-2047 ◽  
Author(s):  
K Howard ◽  
M Kane ◽  
A Madden ◽  
J P Gosling ◽  
P F Fottrell
Keyword(s):  
Detection Limit ◽  
Analytical Procedure ◽  
Solid Phase ◽  
Medical Applications ◽  
Microtiter Plates ◽  
Large Numbers ◽  
Coefficients Of Variation ◽  
Serial Sampling ◽  
Direct Solid

Abstract This competitive, solid-phase enzymoimmunoassay for testosterone in saliva is carried out on microtiter plates and involves no chromatographic or extraction steps. With an overnight incubation the detection limit of the assay is 230 fg per well (16.1 pmol/L). There was a good correlation (correlation coefficient 0.95) between testosterone concentrations measured with and without prior extraction of the saliva samples. Repeated assay of three control saliva samples containing a range of testosterone concentrations (200-1000 pmol/L) gave within- and between-assay coefficients of variation of 5.5-13.2%. The analytical procedure is simple and closely resembles already published procedures for the determination of progesterone and estrone (with extraction) in saliva. One person can assay 200 samples in 24 h and the assay is suitable for reproductive and sports medical applications, particularly for projects involving serial sampling and yielding large numbers of samples.

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