Gmelin's test

Summary

This procedure describes a test to detect the presence of bile salts in urine using a method called Melon’s Test. The process involves adding 5 ml of concentrated nitric acid to a test tube and then carefully introducing 5 ml of the urine sample along the sides of the test tube. A colored ring—green, blue, yellow, or red—forming at the junction of the two solutions indicates the presence of bile pigments, confirming a positive result for bile salts in the urine.

Takeaways

• 😀 Bile salts can be detected in a urine sample using a simple chemical test.
• 😀 The test involves the use of concentrated nitric acid and urine sample in a test tube.
• 😀 5 ml of concentrated nitric acid is added to the test tube as the first step.
• 😀 5 ml of the urine sample is carefully added to the test tube along the sides to avoid mixing initially.
• 😀 The key indication of the presence of bile salts is the formation of a colored ring at the junction of the two liquids.
• 😀 The colored ring can appear in different colors, such as green, blue, yellow, or red.
• 😀 The appearance of the ring signifies the presence of bile pigments in the urine sample.
• 😀 The test primarily detects bile pigments rather than bile salts themselves.
• 😀 The different colors of the ring provide a qualitative indication of bile pigment presence.
• 😀 This method is relatively simple and can be performed in a standard laboratory setting.

Q & A

What is the purpose of the Melon’s test in this procedure?

The purpose of Melon’s test is to detect the presence of bile pigments in a urine sample.

What is the first step of the Melon’s test procedure?

The first step is to take 5 mL of concentrated nitric acid and place it in a test tube.

How should the urine sample be added to the test tube during the Melon’s test?

The urine sample should be added slowly along the sides of the test tube to form a layered solution.

What indicates the presence of bile pigments in the urine sample during this test?

The formation of a green, blue, yellow, or red ring at the junction of the two solutions indicates the presence of bile pigments.

What does the formation of a colored ring suggest in the test?

The formation of a colored ring (green, blue, yellow, or red) suggests that bile pigments, such as bilirubin, are present in the urine.

What is the role of nitric acid in Melon’s test?

Nitric acid acts as a reagent to help react with bile pigments in the urine, enabling their detection.

Why is it important to add the urine sample slowly along the sides of the test tube?

Adding the urine sample slowly along the sides of the test tube helps maintain the layered structure of the two liquids, allowing for a clearer observation of the color change.

What type of pigments does this test detect in the urine?

Melon’s test detects bile pigments, particularly bilirubin, which can indicate liver or bile duct conditions.

What precautions should be taken when performing this test?

Safety precautions should be taken when handling concentrated nitric acid, as it is a hazardous chemical. Proper protective equipment like gloves and goggles should be worn.

What is the significance of the color change at the junction of the two solutions?

The color change at the junction of the two solutions indicates that bile pigments, typically found in bile, are present in the urine, which may be a sign of liver dysfunction or bile duct obstruction.