scholarly journals Using Cholinesterases and Immobilized Luminescent Photobacteria for the Express-Analysis of Mycotoxins and Estimating the Efficiency of Their Enzymatic Hydrolysis

Toxins ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 34
Author(s):  
Elena Efremenko ◽  
Olga Maslova ◽  
Nikolay Stepanov ◽  
Anvar Ismailov
Keyword(s):  
Quantitative Analysis ◽  
Ochratoxin A ◽  
Limit Of Detection ◽  
Scientific Practice ◽  
Rapid Analysis ◽  
Organophosphorus Hydrolase ◽  
Enzyme Efficiency ◽  
Express Analysis ◽  
First Time

Novel sensitive analytical agents that can be used for simple, affordable, and rapid analysis of mycotoxins are urgently needed in scientific practice, especially for the screening of perspective bio-destructors of the toxic contaminants. We compared the characteristics of a rapid quantitative analysis of different mycotoxins (deoxynivalenol, ochratoxin A, patulin, sterigmatocystin, and zearalenone) using acetyl-, butyrylcholinesterases and photobacterial strains of luminescent cells in the current study. The best bioindicators in terms of sensitivity and working range (μg/mL) were determined as follows: Photobacterium sp. 17 cells for analysis of deoxynivalenol (0.8–89) and patulin (0.2–32); Photobacterium sp. 9.2 cells for analysis of ochratoxin A (0.4–72) and zearalenone (0.2–32); acetylcholinesterase for analysis of sterigmatocystin (0.12–219). The cells were found to be more sensitive than enzymes. The assayed strains of photobacterial cells ensured 44%–83% lower limit of detection for deoxynivalenol and sterigmatocystin as compared to the previously known data for immobilized luminescent cells, and the range of working concentrations was extended by a factor of 1.5–3.5. Calibration curves for the quantitative determination of patulin using immobilized photobacteria were presented in this work for the first time. This calibration was applied to estimate the enzyme efficiency for hydrolyzing mycotoxins using zearalenone and His6-tagged organophosphorus hydrolase as examples.

scholarly journals Determination of Flavonoids Compounds of Three Species and Different Harvesting Periods in Crataegi folium Based on LC-MS/MS

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1602
Author(s):  
Ya-Ping Guo ◽  
Hong Yang ◽  
Ya-Li Wang ◽  
Xiao-Xiang Chen ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Qualitative Analysis ◽  
Quantitative Method ◽  
Total Content ◽  
Qualitative And Quantitative Analysis ◽  
Pharmacological Activities ◽  
Time Saving ◽  
Qualitative And Quantitative ◽  
First Time

Crataegi folium have been used as medicinal and food materials worldwide due to its pharmacological activities. Although the leaves of Crataegus songorica (CS), Crataegus altaica (CA) and Crataegus kansuensis (CK) have rich resources in Xinjiang, China, they can not provide insights into edible and medicinal aspects. Few reports are available on the qualitative and quantitative analysis of flavonoids compounds of their leaves. Therefore, it is necessary to develop efficient methods to determine qualitative and quantitative flavonoids compounds in leaves of CS, CA and CK. In the study, 28 unique compounds were identified in CS versus CK by qualitative analysis. The validated quantitative method was employed to determine the content of eight flavonoids of the leaves of CS, CA and CK within 6 min. The total content of eight flavonoids was 7.8–15.1 mg/g, 0.1–9.1 mg/g and 4.8–10.7 mg/g in the leaves of CS, CA and CK respectively. Besides, the best harvesting periods of the three species were from 17th to 26th September for CS, from 30th September to 15th October for CA and CK. The validated and time-saving method was successfully implemented for the analysis of the content of eight flavonoids compounds in CS, CA and CK for the first time.

scholarly journals The Application of a Cadmium Reducer and a Diazotisation Reaction for the Determination of Nitrate and Nitrite in Tobacco / Über die Anwendung des Cadmium-Reduktors und der Diazotierung zur Bestimmung von Nitrat und Nitrit im Tabak

1965 ◽  
Vol 3 (2) ◽  
Author(s):  
U. Dölberg
Keyword(s):  
Quantitative Analysis ◽  
Reduction Method ◽  
Limit Of Detection ◽  
Nitrate And Nitrite ◽  
Inferior Limit

AbstractNitrate is reduced by means of a cadmium reducer and spectrophotometrically determined in the form of nitrite by a diazotisation reaction. The results obtained by application of the described method to tobacco extracts correspond well to those resulting from the earlier described dimethylphenol procedure. Owing to its better sensitivity and specifity the reduction method is particularly suitable for the quantitative analysis of smallest amounts of nitrate. Quantities of 0.03 % of nitrate can be determined without difficulties. The inferior limit of detection is 0.001 %.

Method Validation for the Quantitative Analysis of Aflatoxins (B1, B2, G1, and G2) and Ochratoxin A in Processed Cereal-Based Foods by HPLC with Fluorescence Detection

2015 ◽  
Vol 98 (4) ◽  
pp. 939-945 ◽  
Author(s):  
Işil Gazioğlu ◽  
Ufuk Kolak
Keyword(s):  
Quantitative Analysis ◽  
Simultaneous Determination ◽  
Ochratoxin A ◽  
Fluorescence Detection ◽  
Aflatoxin B1 ◽  
Hplc Analysis ◽  
Extraction Procedure ◽  
Immunoaffinity Column ◽  
Rp Hplc

Abstract Modified AOAC 991.31 and AOAC 2000.03 methods for the simultaneous determination of total aflatoxins (AFs), aflatoxin B1, and ochratoxin A (OTA) in processed cereal-based foods by RP-HPLC coupled with fluorescence detection were validated. A KOBRA® Cell derivatization system was used to analyze total AFs. One of the modifications was the extraction procedure of mycotoxins. Both AFs and OTA were extracted with methanol–water (75 + 25, v/v) and purified with an immunoaffinity column before HPLC analysis. The modified methods were validated by measuring the specificity, selectivity, linearity, sensitivity, accuracy, repeatability, reproducibility, recovery, LOD, and LOQ parameters. The validated methods were successfully applied for the simultaneous determination of mycotoxins in 81 processed cereal-based foods purchased in Turkey. These rapid, sensitive, simple, and validated methods are suitable for the simultaneous determination of AFs and OTA in the processed cereal-based foods.

Determination of formaldehyde by flow injection analysis with spectrophotometric detection exploiting brilliant green–sulphite reaction

2015 ◽  
Vol 69 (6) ◽  
Author(s):  
Lúcio Bolognesi ◽  
Eder J. dos Santos ◽  
Gilberto Abate
Keyword(s):  
Flow Injection ◽  
Flow Injection Analysis ◽  
Brilliant Green ◽  
Limit Of Detection ◽  
Spectrophotometric Detection ◽  
Sample Throughput ◽  
First Time

AbstractA method for the determination of formaldehyde by flow injection analysis with spectrophotometric detection is proposed, based on retarding the reaction between brilliant green and sulphite by the addition of formaldehyde; this was investigated for formaldehyde quantification in extracts from wood-based panels. For the first time, a heating step was explored, providing a sample throughput of 50 analyses per hour, with a limit of detection of 0.02 mg L

scholarly journals Development and validation of a SPE-UHPLC-fluorescence method for the analysis of ochratoxin-a in certain Turkish wines

2019 ◽  
Vol 38 (2) ◽  
pp. 161
Author(s):  
Elif Mine Oncu Kaya
Keyword(s):  
Ochratoxin A ◽  
Mobile Phase ◽  
High Performance ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Internal Standard ◽  
Fluorescence Method ◽  
Limit Of Quantitation ◽  
Development And Validation

A sensitive Ultra-High Performance Liquid Chromatography (UHPLC)-fluorescence method was developed and validated for the determination of ochratoxin-A (OTA) in Turkish wine samples. Naphthalene was used as an internal standard in this study. OTA was separated on a C18 (3.0 mm × 100 mm × 1.8 µm) column and analyses were run under isocratic conditions, with a mobile phase consisting of water/acetonitrile/acetic acid (50:50:1, v/v/v). The flow rate and injection volume were 0.5 ml min−1 and 10 μl, respectively. The excitation and emission wavelengths were 330 nm and 460 nm for OTA, respectively, and 220 nm and 325 nm for internal standard, respectively. A solid-phase extraction (SPE) clean-up procedure on a C18 cartridge was used prior to the analysis of the wine samples by UHPLC. The developed method was validated with respect to linearity, precision, accuracy, limit of detection (LOD), limit of quantitation (LOQ), stability and robustness. The method presented good RSD (< 4 %) and recovery (102.6–105.2 %) values. The LOD and LOQ values were 0.01 ng ml–1 and 0.05 ng ml–1, respectively. All other parameters were acceptable. OTA amounts were found in the range of 2.72‒7.40 µg kg‒1 in the Turkish wine samples.

scholarly journals Liquid Chromatographic Method with Immunoaffinity Column Cleanup for Determination of Ochratoxin A in Barley: Collaborative Study

2000 ◽  
Vol 83 (6) ◽  
pp. 1377-1383 ◽  
Author(s):  
A Catherine Entwisle ◽  
Alison C Williams ◽  
Peter J Mann ◽  
Philip T Slack ◽  
John Gilbert
Keyword(s):  
Standard Deviation ◽  
Ochratoxin A ◽  
Relative Standard Deviation ◽  
Limit Of Detection ◽  
Collaborative Study ◽  
Immunoaffinity Column ◽  
Low Level ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract A collaborative study was conducted to evaluate a liquid chromatographic (LC) method with immunoaffinity column cleanup for determination of ochratoxin A. The method was tested at 3 concentration levels of ochratoxin A in barley, which represent possible future European regulatory limits. The test portion was extracted with acetonitrile–water by blending at high speed. The extract was filtered, diluted with phosphate-buffered saline (PBS), and applied to an ochratoxin A immunoaffinity column. The column was washed with water and the ochratoxin A eluted with methanol. The solvent was then evaporated and the residue redissolved in injection solvent. After injection of this solution onto reversed-phase LC column, ochratoxin A was measured by fluorescence detection. Eight samples of low level naturally contaminated barley and 2 samples of blank barley (ochratoxin A not found at the limit of detection of 0.2 μg/kg at the signal-to-noise ratio of 3 to 1) were sent, along with ampules of ochratoxin A, calibrant, and spiking solutions, to 15 laboratories in 13 different European countries. Test portions were spiked with ochratoxin A at levels of 4 ng/g, and recoveries ranged from 65 to 113%. Based on results for spiked samples (blind duplicates) and naturally contaminated samples (blind duplicates at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 4 to 24%, and the relative standard deviation for reproducibility (RSDR) ranged from 12 to 33%. The method showed acceptable within- and between-laboratory precision, as evidenced by HORRAT values, at the low level of determination for ochratoxin A in barley.

Determination of Picogram Levels of Levodopa in Pharmaceutical Preparations and Biofluids by Flow-Injection Chemiluminescence

2014 ◽  
Vol 884-885 ◽  
pp. 566-569 ◽  
Author(s):  
Yun Zhang ◽  
Su Ya Gao
Keyword(s):  
Flow Injection ◽  
Limit Of Detection ◽  
Pharmaceutical Preparations ◽  
Human Saliva ◽  
Quenching Effect ◽  
Dopa Concentration ◽  
Flow Injection Chemiluminescence ◽  
First Time ◽  
Serum And Urine

An ultrasensitive method for determination of L-dopa at picogram levels by flow-injection chemiluminescence (FI-CL) as presented for the first time, based on the quenching effect of levodopa (L-dopa) on the luminol-lysozyme reaction. It was found that the decrement of CL intensity was linearly proportional to the logarithm of L-dopa concentration ranging from 3.0 to 7.0 × 103pg mL-1(R= 0.9967), with the limit of detection (LOD) of 1.0 pg mL-1(3σ). The proposed procedure was successfully applied to the determination of L-dopa in pharmaceutical preparations, human saliva, serum, and urine samples with the recoveries ranging from 96.7% to 104.3% and RSDs less than 4.0% (n= 5).

scholarly journals Fabrication of a Novel Electrochemical Sensor Based on Carbon Cloth Matrix Functionalized with MoO3 and 2D-MoS2 Layers for Riboflavin Determination

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1371
Author(s):  
Rayhane Zribi ◽  
Antonino Foti ◽  
Maria Grazia Donato ◽  
Pietro Giuseppe Gucciardi ◽  
Giovanni Neri
Keyword(s):  
Electrochemical Sensor ◽  
Limit Of Detection ◽  
Carbon Cloth ◽  
Electrochemical Characteristics ◽  
Mos2 Nanosheets ◽  
Fiber Network ◽  
Screen Printed Carbon Electrode ◽  
First Time

The preparation and characterization of a hybrid composite, based on carbon cloth (CC) matrix functionalized with two-dimensional (2D) MoS2 flakes and MoO3, and its use for developing an electrochemical sensor for the determination of riboflavin (RF) is here reported. The 2D-MoS2-MoO3CC composite was prepared by depositing 2D-MoS2 nanosheets, obtained by liquid phase exfoliation (LPE), on the surface of a carbon cloth fiber network, previously functionalized with a layer of molybdenum oxide (α-MoO3) by radio-frequency magnetron reactive sputtering technique. The 2D-MoS2-MoO3CC composite was characterized by scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX), and Raman spectroscopy. An electrochemical sensor has been then fabricated by fixing a slice of the 2D-MoS2-MoO3CC composite on the working electrode of a screen-printed carbon electrode (SPCE). The 2D-MoS2-MoO3-CC/SPCE sensor display good electrochemical characteristics which have been exploited, for the first time, in the electroanalytical determination of riboflavin (RF). The sensitivity to RF, equal to 0.67 µA mM−1 in the linear range from 2 to 40 µM, and a limit of detection (LOD) of 1.5 µM at S/N = 3, demonstrate the promising characteristics of the proposed 2D-MoS2-MoO3-CC/SPCE electrochemical sensor for the determination of riboflavin.

scholarly journals Determination of tyrosine by sodium fluorescein-enhanced ABEI–H2O2–horseradish peroxidase chemiluminescence

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bin Dong ◽  
Qian Fan ◽  
Ming Li ◽  
Yanfu Huan ◽  
Guodong Feng ◽  
...  
Keyword(s):  
Horseradish Peroxidase ◽  
Limit Of Detection ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Linear Range ◽  
Hydroxyl Group ◽  
Sodium Fluorescein ◽  
First Time ◽  
Energy Acceptor

AbstractIn this study, N-(4-aminobutyl)-N-ethylisoluminol (ABEI) was used as an energy donor, while sodium fluorescein was used as an enhancer and energy acceptor, which resulted in it producing resonance energy transfer and greatly increasing the strength of chemiluminiscence (CL). When horseradish peroxidase (HRP) is added, hydrogen peroxide (H2O2) will quickly separate into hydroxyl radicals (·OH) and superoxide ions (O2·−). If tyrosine (Tyr) is present in the system, the hydroxyl group on the benzene ring of Tyr robs ·OH and O2·− in the CL system, thereby reducing the intensity of CL. Based on this phenomenon, a luminescence system of ABEI and sodium fluorescein system was established to detect Tyr for the first time. This method has an ultra-low detection limit and a wide linear range, and is cheap and easy to operate. Under various optimal conditions, the linear range is from 3.0×10−8 to 3.0×10−5 mol/L, and the limit of detection is 2.4×10−8 mol/L. It has been successfully used in the detection of dairy products with satisfactory results.

scholarly journals High-Performance Liquid Chromatography Determination of Free Sugars and Mannitol in Mushrooms Using Corona Charged Aerosol Detection

2020 ◽  
Author(s):  
Aneta Sławińska ◽  
Ewa Jabłońska-Ryś ◽  
Anna Stachniuk
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Limit Of Detection ◽  
Free Sugars ◽  
Charged Aerosol ◽  
Charged Aerosol Detector ◽  
Refractive Index Detector ◽  
First Time

Abstract Refractive index detector is usually used in the analysis of sugars in mushrooms, which is characterized by poor sensitivity, reproducibility, and susceptibility to interference from co-eluting sample components. In the current study, identification and determination of free sugars in mushroom samples by high-performance liquid chromatography coupled to corona charged aerosol detector (HPLC-CAD) were presented for the first time. The best chromatographic separation was performed on a Shodex Asahipak NH2P-50 4E 5 μm and mobile phase composed of 75% acetonitrile and 25% water with flow rate was 1 mL/min. The developed method offers good linearity in concentration range 0.001–0.01 or 0.01–0.2 mg/mL for tested compounds with R2 > 0.99. Limit of detection (LOD) for analytes was in the range of 7.1–120.2 ng on column. HPLC-CAD method showed very good reproducibility (RSD < 5.1%). Fructose, mannitol, and glucose were detected in all examined mushroom samples. For white Agaricus bisporus, mannitol was the most abundant sugar (7.575 mg/g dw), whereas trehalose for Pleurotus ostreatus (3.426 mg/g dw). The developed method was successfully applied for quantification of free sugars and mannitol in mushrooms. The optimized method proved to be sensitive, reproducible, and accurate.

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