Instrument to detect the color of the solution is?

BHU NO - 2015

Biochemistry and Nutrition

Easy

Appeared in: BHU NO - 2015

Explanation

A colorimeter is specifically designed to measure the absorbance of a particular wavelength of light by a colored solution.
This measurement is based on the Beer-Lambert law, which states that the absorbance of light is directly proportional to the concentration of the colored substance.
Therefore, by measuring the intensity of the color, a colorimeter can determine the concentration of a solute in a solution.
It is the standard instrument for quantifying colored solutions in the visible light spectrum (400-800 nm).

Option A: A calorimeter measures heat (energy), not color. The prefix 'calor' refers to heat (calories).
Option B: A flame photometer measures the light emitted by excited atoms in a flame to determine the concentration of specific elements, primarily alkali and alkaline earth metals (e.g., sodium, potassium). It does not measure the color of a solution.
Option C: Chromatography is a technique used to separate a mixture into its individual components. It does not measure color or concentration directly.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Principles and applications of common laboratory instruments as background academic context rather than a clinical decision trigger.
In nursing and clinical practice, understanding the principle of colorimetry is crucial as it forms the basis for many routine lab tests (e.g., blood glucose, hemoglobin A1c, kidney function tests like creatinine).
Nurses often collect samples for these tests and must understand the importance of proper sample handling to ensure accurate colorimetric analysis.
What if? If a patient's blood sample for a glucose test was hemolyzed (red blood cells ruptured), the red color from hemoglobin would interfere with the colorimetric reading, leading to a falsely high or inaccurate glucose result. This highlights the need for correct phlebotomy technique.

How to Approach the Question

First, analyze the keywords in the question: 'instrument', 'detect', and 'color of the solution'. The key function required is measuring color.
Examine the options and look for a term related to 'color'. The prefix 'colori-' in 'Colorimeter' is a strong clue.
Consider the function of the other instruments. 'Calorimeter' has 'calor' (heat). 'Flame photometer' involves a flame. 'Chromatography' involves 'chroma' (color) but is a separation technique ('-graphy').
Recall or deduce the primary function of each instrument. A colorimeter is a 'meter' for 'color', making it the most logical choice for measuring the color of a solution.
Confirm the choice by eliminating the other options based on their known functions (heat measurement, elemental analysis, separation).

Concept Tested & Keywords

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E6 Biochemistry U Satyanarayana— Part 2 (pp 421-820 of 840) p. 388-390

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart B (pp 240-463 of 478) pp. 77-79, 76-78