What is the function of picric acid in creatinine determination?

Answer 1

Picric acid sits at the heart of the classic Jaffe reaction, one of the oldest and most widely used ways to estimate creatinine in the lab.

What does it actually do?

In alkaline conditions, picric acid reacts with creatinine to produce a reddish-orange color. This is the Jaffe reaction. The stronger the color, the more creatinine there is in the sample.

In short, picric acid acts as a chromogenic reagent. It creates a color that tells you how much creatinine you have.

Here’s how the process goes:

1. You mix the sample, could be blood, serum, or urine, with an alkaline picrate solution.

2. Creatinine reacts with the picric acid.

3. A colored complex forms.

4. You measure how strong that color is with a spectrophotometer.

5. The absorbance tells you the creatinine concentration.

There’s a hitch, though: The Jaffe method isn’t perfectly specific. Other substances, like glucose, proteins, ketones, even some drugs, also react with picric acid. These are the so-called non-creatinine chromogens, and they can make the results appear higher than they really are.

Because of this lack of specificity, many labs now use enzymatic creatinine assays, which give more accurate results.

Answer 2

Picric acid reacts with creatinine to form a colored complex that can be measured spectrophotometrically. This reaction is used in the Jaffe method for creatinine determination. The intensity of the color produced is directly proportional to the concentration of creatinine in the sample.

Answer 3

it functions to bind at creatinine for detection under a spectophotometer at a certain wavelength