Estimation of Dextrose by Colorimetry

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Learn estimation of Dextrose by colorimetry with principle, requirements, reagents, procedure and more. It is useful for biochemical analysis.

Estimation of Dextrose by Colorimetry

In the field of biochemical analysis, the estimation of dextrose (glucose) plays a vital role in various industries, including food production and clinical diagnostics. Colorimetry, a widely used analytical technique, offers a simple and effective method for determining the concentration of dextrose in a given sample. In this blog post, we will explore the principle behind colorimetric analysis, provide a step-by-step procedure, and discuss its significance in laboratory settings.

Principle of Colorimetry for Dextrose Estimation

The principle of colorimetry relies on the reaction between dextrose and copper ions in an alkaline medium. When dextrose reacts with copper ions in the presence of an alkaline solution. It forms a colored complex. The intensity of the color produced is directly proportional to the concentration of dextrose in the sample. By measuring the absorbance of this colored complex at a specific wavelength using a colorimeter or spectrophotometer, we can quantitatively determine the concentration of dextrose in the sample.

Requirements

  1. Reagents and Chemicals:
    • Copper sulfate: 1% solution
    • Sodium potassium tartrate (Rochelle salt): 20% solution
    • Sodium hydroxide: 10% solution
    • Dextrose standard solutions of known concentrations
    • Distilled water
  2. Laboratory Equipment:
    • Test tubes or cuvettes
    • Colorimeter or spectrophotometer capable of measuring absorbance at a specific wavelength (e.g., 540 nm)
    • Pipettes or graduated cylinders for accurate volume measurements
    • Vortex mixer or suitable means for mixing the reaction mixture
    • Timer or clock for timekeeping during the reaction

Procedure

  1. Preparation of Reagents: To begin, prepare the following reagents:
    • 1% copper sulfate solution
    • 20% sodium potassium tartrate (Rochelle salt) solution
    • 10% sodium hydroxide solution
    • Series of dextrose standard solutions of known concentrations
  2. Reaction Mixture Preparation:
    • Take 2 ml of the dextrose sample solution or the standard solution in a test tube.
    • Add 2 ml of the copper sulfate solution.
    • Add 2 ml of the sodium potassium tartrate solution.
    • Thoroughly mix the contents by gently shaking the test tube.
    • Allow the mixture to stand at room temperature for 10 minutes.
  3. Colorimetric Measurement:
    • After 10 minutes, measure the absorbance of the reaction mixture using a colorimeter or spectrophotometer at a specific wavelength (e.g., 540 nm).
    • Use distilled water as a blank reference to calibrate the instrument.
  4. Calibration Curve:
    • Prepare a calibration curve by plotting the absorbance values obtained from the standard solutions on the y-axis against the corresponding concentrations on the x-axis.
    • Utilize linear regression analysis to determine the equation of the calibration curve (y = mx + c), where y represents absorbance, x represents concentration, m represents the slope, and c represents the intercept.
  5. Sample Analysis:
    • Measure the absorbance of the dextrose sample using the same procedure as in step 3.
    • Determine the concentration of dextrose in the sample by substituting the absorbance value into the equation of the calibration curve obtained in step 4.

Significance of Colorimetric Analysis for Dextrose Estimation

Colorimetry offers several advantages for estimating dextrose concentration in laboratory settings:

  • Simplicity: The procedure is relatively straightforward, making it accessible to researchers and technicians with varying levels of expertise.
  • Sensitivity: Colorimetric analysis provides a sensitive method for detecting even low concentrations of dextrose in samples.
  • Speed: The reaction between dextrose and copper ions occurs relatively quickly, enabling rapid analysis and high sample throughput.
  • Cost-effectiveness: The reagents used in colorimetric analysis are generally inexpensive, making this method cost-effective for routine analysis.
  • Wide Applicability: Colorimetry can be applied to various sample types, including biological fluids, food products, and pharmaceutical formulations.

Conclusion: Colorimetry is a valuable tool in the laboratory for estimating dextrose concentration in diverse applications. By understanding the principle behind

Also read What is HPTLC? principle and applications. Column chromatography methodology and applications.

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