Method for dynamic determination of time constants, method for level detection, method for compressing an electric audio signal and hearing aid, wherein the method for compression is used

Background: Determination of a reducing substance based on the reaction between Ce(IV) and a reducing substance and fluorescence detection of Ce(III) generated has been reported as a selective and sensitive method. However, this method could not be applied to the determination of alcohol due to the low reaction rate of alcohol and Ce(IV). Objective: We found that thiosulfate catalytically enhanced reaction of alcohols (such as, methanol, ethanol, and propanol) and Ce(IV). Utilizing this effect, we developed a new method for the determination of alcohols. Results: In the presence of thiosulfate, an increase in fluorescence intensity was detected by injecting alcohol at concentrations of several millimolar, whereas it was not observed even at the concentration of 10% v/v (2 M for ethanol) in the absence of thiosulfate. The optimum detection conditions were determined to be 4.0 mM Ce(IV) sulfate and 0.50 mM thiosulfate, and the detection limit (S/N = 3) of ethanol under these conditions was 1 mM. In the calibration curves, changes in the slope were observed when the alcohol concentrations were approximately 10–25 mM. Using a thiosulfate solution containing ethanol as the reaction solution, a calibration curve without any change in slope was obtained, although the concentration of ethanol at the detection limit increased. The alcohols in the liquor and fuel were successfully analyzed using the proposed detection method as a postcolumn reaction. Conclusion: This new alcohol detection method using a versatile fluorescence detector can be applied to the postcolumn reaction of HPLC omitting need of time-consuming pretreatment processes.

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A Rapid and Simple Dual-Channeled Capillary Electrophoresis with Contactless Conductivity Detection Method for the Determination of Adenosine, Cordycepin, and Inosine in Ophiocordyceps sinensis-Based Products

Food Analytical Methods ◽

10.1007/s12161-021-02003-6 ◽

2021 ◽

Author(s):

Thanh Dam Nguyen ◽

Minh Tuan Vu ◽

Manh Huy Nguyen ◽

Hong Anh Duong ◽

Thanh Duc Mai ◽

...

Keyword(s):

Capillary Electrophoresis ◽

Detection Method ◽

Conductivity Detection ◽

Contactless Conductivity Detection ◽

Ophiocordyceps Sinensis

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Immobilization-Free Electrochemical Sensor Coupled with a Graphene-Oxide-Based Aptasensor for Glycated Albumin Detection

Biosensors ◽

10.3390/bios11030085 ◽

2021 ◽

Vol 11 (3) ◽

pp. 85

Author(s):

Wassa Waiwinya ◽

Thitirat Putnin ◽

Dechnarong Pimalai ◽

Wireeya Chawjiraphan ◽

Nuankanya Sathirapongsasuti ◽

...

Keyword(s):

Graphene Oxide ◽

Electrochemical Sensor ◽

Detection Method ◽

Limit Of Detection ◽

Glycated Albumin ◽

Cost Effective ◽

Logarithmic Scale ◽

Electrochemical Aptasensor ◽

Alternative Approach

An immobilization-free electrochemical sensor coupled with a graphene oxide (GO)-based aptasensor was developed for glycated human serum albumin (GHSA) detection. The concentration of GHSA was monitored by measuring the electrochemical response of free GO and aptamer-bound GO in the presence of glycated albumin; their currents served as the analytical signals. The electrochemical aptasensor exhibited good performance with a base-10 logarithmic scale. The calibration curve was achieved in the range of 0.01–50 µg/mL. The limit of detection (LOD) was 8.70 ng/mL. The developed method was considered a one-drop measurement process because a fabrication step and the probe-immobilization process were not required. This simple sensor offers a cost-effective, rapid, and sensitive detection method, and could be an alternative approach for determination of GHSA levels.

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