scholarly journals Construction of a Hydrogel Pectin-Based Triglyceride Optical Biosensor with Immobilized Lipase Enzymes

Biosensors ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 135 ◽  
Author(s):  
Uswatun Hasanah ◽  
Nor Diyana Md Sani ◽  
Lee Yook Heng ◽  
Rinaldi Idroes ◽  
Eka Safitri
Keyword(s):  
Standard Deviation ◽  
Optimum Condition ◽  
Limit Of Detection ◽  
Immobilized Lipase ◽  
Optical Biosensor ◽  
Buffer Concentration ◽  
Enzyme Loading ◽  
Relative Standard ◽  
Hydrogel Membrane ◽  
Biosensor Response

A novel and simple optical biosensor to detect triglycerides (TGs) has been successfully constructed by using pectin hydrogel membrane as the indicator pH and chromoionophore ETH 5294 (CI), with lipase as the catalyst. The enzymatic working system against TGs releasing H+ ions will affect the color absorbance of CI. The characterization results show that a TG biosensor has the optimum condition and sensitivity at the phosphate buffer concentration of 50 mM, pH 7, and enzyme loading of 60 μg. The biosensor works at the tripalmitin (TP) concentration range of 100–400 mg/dL. With the sensitivity of 0.001 (∆A/(mg/dL)), the biosensor response reaches stability after five minutes, and the limit of detection (LOD) of the TG optical biosensor is 15 mg/dL. Relative standard deviation (RSD) in a reproducibility test was 2.5%, with a 15-day lifespan.

A Highly Sensitive and Label-Free Microbead-Based ‘Turn-On’ Colorimetric Sensor for the Detection of Mercury(II) in Urine Using a Peroxidase-Like Split G-Quadruplex–Hemin DNAzyme

2018 ◽  
Vol 71 (12) ◽  
pp. 945
Author(s):  
Xin Fu ◽  
He Zhang ◽  
Jie Zhang ◽  
Shi-Tong Wen ◽  
Xing-Cheng Deng
Keyword(s):  
Standard Deviation ◽  
Base Pair ◽  
Limit Of Detection ◽  
Label Free ◽  
Turn On ◽  
Highly Sensitive ◽  
Relative Standard ◽  
G Quadruplex ◽  
Catalytically Active ◽  
Partial Cdna

A highly sensitive and label-free microbead-based ‘turn-on’ assay was developed for the detection of Hg2+ in urine based on the Hg2+-mediated formation of intermolecular split G-quadruplex–hemin DNAzymes. In the presence of Hg2+, T–T mismatches between the two partial cDNA strands were stabilized by a T–Hg2+–T base pair, and can cause the G-rich sequences of the two oligonucleotides to associate to form a split G-quadruplex which is able to bind hemin to form the catalytically active G-quadruplex–hemin DNAzyme. This microbead-based ‘turn-on’ process allows the detection of Hg2+ in urine samples at concentrations as low as 0.5 pM. The relative standard deviation and recovery are 1.2–3.9 and 98.7–103.2%, respectively. The remarkable sensitivity for Hg2+ is mainly attributed to the enhanced mass transport ability that is inherent in homogeneous microbead-based assays. Compared with previous developments of intermolecular split G-quardruplex–hemin DNAzymes for the homogeneous detection of Hg2+ (the limit of detection was 19nM), a signal enhancement of ~1000 times is obtained when such an assay is performed on the surface of microbeads.

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.

Kinetic Spectrophotometric Determination of Ruthenium by its Catalytic Effect on the Reduction of Spadns with Sodium Hypophosphite in Micellar Media

2012 ◽  
Vol 204-208 ◽  
pp. 4067-4070 ◽  
Author(s):  
Zhi Rong Zhou ◽  
Li Zhen Zhang
Keyword(s):  
Standard Deviation ◽  
Spectrophotometric Method ◽  
Catalytic Effect ◽  
Limit Of Detection ◽  
Fixed Time ◽  
Sodium Hypophosphite ◽  
Micellar Media ◽  
Relative Standard ◽  
Kinetic Spectrophotometric

A simple kinetic spectrophotometric method was developed for the determination of trace amounts of Ru (III). The method is based on the reduction of spadns by sodium hypophosphite (NaH2PO2) in micellar media. The reaction was monitored spectrophotometrically by measuring the decrease in the absorbance of spadns at 515 nm with a fixed-time method. The decrease in the absorbance of spadns is proportional to the concentration of Ru (III) in the range 0.40–10.0 μg/L with a fixed time of 2.5–7.0 min from the initiation of the reaction. The limit of detection is 0.12 μg/L Ru (III). The relative standard deviation for the determination of 0.10 and 0.20 μg/25mL Ru (III) was 2.3 % and 2.0 %, respectively. The method was applied to the determination of Ru (III) in some ores and metallurgy products.

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.

Preparation of Adsorbents Based on Dendrimer Modified Silica Gel and its Adsorption Performances for Lead

2013 ◽  
Vol 800 ◽  
pp. 166-172
Author(s):  
Xiong Zhi Wu ◽  
Li Li ◽  
Fei Ping Li ◽  
Wen Ying Jin
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Silica Gel ◽  
Limit Of Detection ◽  
Modified Silica ◽  
Modified Silica Gel ◽  
Flame Atomic Absorption ◽  
Relative Standard ◽  
Separation And Preconcentration

A new sorbent (PAMAM4.0GASG) with gallic acid as functional group has been prepared based on G4.0 polyamidoamine dendrimer modified silica gel (PAMAM4.0SG) and characterized with FTIR. It was employed for selective separation, preconcentration and determination of lead in different samples by flame atomic absorption spectrometry (FAAS). Experimental conditions for effective separation and preconcentration of lead were optimized. The preconcentration factor reaches 200 for lead. The relative standard deviation (R.S.D.) under optimum conditions was 2.1% for 5.0 μg ml1 of Pb (II).The relative standard deviation (R.S.D.) was 2.1% for 5.0 μg ml1 of Pb (II). The limit of detection (LOD) of 0.081μg ml1 was achieved with a sample loading flow rate of 4.2 ml min1 and a 10 ml sample volume in the proposed method. The proposed column enrichment method was applied for the preconcentration/separation and determination of Pb (II) in tap water and river water samples successfully.

Determination of diltiazem based on the reduction of Cu(II)–BCA complexes in micellar medium

2010 ◽  
Vol 88 (6) ◽  
pp. 533-539 ◽  
Author(s):  
Larissa Zuppardo Lacerda Sabino ◽  
Daniele Cestari Marino ◽  
Horacio Dorigan Moya
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Confidence Level ◽  
Limit Of Detection ◽  
Calibration Graph ◽  
Micellar Medium ◽  
Solution Ph ◽  
Simple Method ◽  
Relative Standard

A simple method was developed for determining microquantities of diltiazem, based on the reduction of copper(II) in buffered solution (pH 7.0) and the use of a micellar medium containing 4,4′-dicarboxy-2,2′-biquinoline acid. The copper(I) produced reacts with 4,4′-dicarboxy-2,2′-biquinoline acid and the complexes formed are spectrophotometrically measured at 558 nm. A typical calibration graph shows good linearity (r = 0.993) from 20 to 100 μg mL–1 of diltiazem. The limit of detection and relative standard deviation were calculated as 12 μg mL–1 (99% confidence level) and 3.5% (40 μg mL–1; n = 6), respectively, with a mean recovery value of 96.5% found in pharmaceutical dosages. A straightforward and effective way to recycle the reagents is addressed. The hazardous aspects of the Cu(I)–BCA reaction are presented as well.

scholarly journals SPECTROPHOTOMETRIC DETERMINATION OF CEFPIROME IN PHARMACEUTICAL PREPARATION

2020 ◽  
pp. 124-127
Author(s):  
DILIP M CHAFLE
Keyword(s):  
Standard Deviation ◽  
Spectrophotometric Method ◽  
Limit Of Detection ◽  
Pharmaceutical Preparation ◽  
Effect Of Temperature ◽  
Percentage Error ◽  
Ferric Nitrate ◽  
Red Color ◽  
Relative Standard

Objective: A simple, sensitive and precise visible spectrophotometric method has been proposed for the determination of cefpirome (CFM) in pure and oral injectable dosage form. Methods: A spectrophotometric method is based on the formation of stable red color product by oxidation of drugs by ferric nitrate and subsequent complexation with 1, 10 – phenanthroline with maximum absorption at 515 nm. Result: The red color complex was formed between Fe (II) and 1, 10 – phenanthroline after reduction of Fe (III) to Fe (II) in the presence of CFM drug. The phosphoric acid solution was used only for quenching the complex formation reaction. Several parameters such as the maximum wavelength of absorption, the volume of reagents, sequence of addition and effect of temperature and time of heating were optimized to achieve high sensitivity, stability and reproducible results. Under the optimum conditions, linear relationship with good correlation coefficient (0.994) was found over the concentration range from 0.20 to 6.00 μg/mL with a molar extinction coefficient 7.7813 × 104 L/mol/cm, limit of detection 0.2026 and limit of quantification 0.6141 μg/mL, respectively. Conclusion: The proposed method was evaluated statistically for linearity, accuracy, and precision in terms of standard deviation, percentage recovery, percentage error and relative standard deviation. The proposed method can be applied for the routine estimation of CFM in the laboratory.

scholarly journals Multiresidue Determination of Pesticides in Drinking and Related Waters by Solid-Phase Extraction and Liquid Chromatography with Ultraviolet Detection: Interlaboratory Study

2002 ◽  
Vol 85 (2) ◽  
pp. 375-383 ◽  
Author(s):  
François van Hoof ◽  
Peter van Wiele ◽  
Françoise Acobas ◽  
Jean-Luc Guinamant ◽  
Auguste Bruchet ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Solid Phase Extraction ◽  
Relative Standard Deviation ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Tap Water ◽  
Phase Extraction ◽  
Relative Standard ◽  
Styrene Divinylbenzene

Abstract As part of a project funded by the European Commission (EC) for the development and evaluation of multiresidue methods for analysis of drinking and related waters, 17 European laboratories evaluated a method using styrene–divinylbenzene copolymer solid-phase extraction followed by liquid chromatography with diode array detection. The main aim of the study was to evaluate whether the method meets the requirements of EC Drinking Water Directive 98/83 in terms of accuracy, precision, and detection limit for 21 pesticides according to the following requirements: limit of detection, ≤0.025 μg/L; accuracy expressed as recovery, between 75 and 125%; and precision expressed as repeatability relative standard deviation of the method, <12.5%, and as reproducibility relative standard deviation of the method, <25%. Analyses for unknown concentrations were performed with commercial bottled and tap waters. All laboratories were able to achieve detection limits of 0.01 μg/L for all pesticides except pirimicarb (0.02 μg/L). The criteria for repeatability were met for all compounds. Terbutryn in bottled water and carbendazim in tap water did not meet the criteria for reproducibility. In terms of accuracy, the method met the requirements for all pesticides in both matrixes, except for metamitron. However, several compounds (linuron, terbutryn, propazine, metobromuron, and isoproturon) showed recoveries slightly below 75%.

scholarly journals Determination of ethylene by field asymmetric ion mobility spectrometry

2020 ◽  
Vol 23 (2) ◽  
pp. 161-166
Author(s):  
Nattapong Chantipmanee ◽  
Peter C. Hauser
Keyword(s):  
Standard Deviation ◽  
Ion Mobility ◽  
Drift Tube ◽  
Limit Of Detection ◽  
Rectangular Pulse ◽  
Kiwi Fruit ◽  
Ion Mobility Spectrometer ◽  
Climacteric Fruit ◽  
Relative Standard

Abstract The determination of ethylene with a field asymmetric ion mobility spectrometer, which can easily be constructed in-house, is described. The device makes use of a Krypton lamp for ionization. A rectangular pulse of 500 Vpp at 1 MHz was employed as separation waveform in the drift tube rather than the commonly used less efficient bisinusoidal waveform. The calibration curve for the range from 670 ppb(V/V) to 67 ppm(V/V) was found to be highly linear with a correlation coefficient of r = 0.9999. The limit of detection was determined as 200 ppb(V/V). The reproducibility was 4% (relative standard deviation). The device was found to be suitable for the determination of ethylene given off by fruit; 6 types of climacteric fruit were tested, namely apples, bananas, kiwi fruit, nectarines, pears and plums.

Simultaneous Determination of Cationic and Anionic Surfactants in Domestic, Sewage and River Effluent by Diffuse Reflectance -Fourier Transform Infrared Spectroscop ic Analysis

2021 ◽  
Vol 30 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Ramsingh Kurrey ◽  
Kaushlya Thakur ◽  
Swati Chandrawanshi ◽  
Manas Kanti Deb
Keyword(s):  
Fourier Transform ◽  
Standard Deviation ◽  
Simultaneous Determination ◽  
Diffuse Reflectance ◽  
Limit Of Detection ◽  
Sodium Dodecyl ◽  
Fourier Transform Infrared ◽  
Domestic Sewage ◽  
Relative Standard

A new, simple, rapid and precise novel hyphenated diffuse reflectance-Fourier transform infrared spectroscopy (DRS-FTIR) technique for the simultaneous determination of the most frequently used cationic surfactants (CS+) i.e. cetyltrimethylammonium bromide (CTAB) and anionic surfactant (AS-) i.e. sodium dodecyl sulphate (SDS) in domestic, sewage and river wastewater samples has been stabilised. CS+ and AS- were analyzed using DRS-FTIR, the most steady and strongest vibrational IR peak at 2917.13 cm-1 for CTAB and 1226.07 for SDS were selected for the simultaneous quantiflcation of CS+ and AS- under the optimized condition such as effect of samples volume and effect of temperature. The limit of detection (LOD) and limit of quantiflcation (LOQ) of the present method were 5 µg/mL and 15 µg/mL, respectively. The absorbance and peak area were determined by the DRS-FTIR method, which shows excellent linearity with a correlation coefflcient value of 0.985 and 0.981 for the concentration range of 10-100 µg/mL. The standard deviation (SD) and relative standard deviation (RSD) for six replicate measurements were found to be 0.052 µg/L and 2.8 %, respectively.

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