UJI KUANTITATIF KARBOHIDRAT MENGGUNAKAN SPEKTROFOTOMETRI

Summary

The script details a step-by-step process for preparing and organizing standard solutions and samples with varying concentrations of 20.40, 6080, and 100 ppm. It instructs on the use of a spectrophotometer, including warming up the device, setting up the photometric matrix with a wavelength of 540, and calibrating with a blank solution using aquadest. The process involves careful pipetting, ensuring cleanliness, and avoiding direct contact with latex gloves to prevent contamination. The instructions emphasize the importance of accuracy and precision in the experimental setup.

Takeaways

• 🔬 Prepare standard solutions and samples with concentrations of 20, 40, 60, 80, and 100 ppm.
• 📦 Arrange the solutions in ascending order of concentration on a rack.
• ⏱ Turn on the spectrophotometer and wait for 15 minutes to warm up.
• 🔑 Press 'OK' to start and gradually proceed with the operation.
• 💧 Prepare a blank solution using distilled water before setting up the spectrophotometer.
• 🔄 Select option number 1 for the photometric matrix and set the wavelength to 540 nm.
• 🧪 Use an auto-zero function to begin the calibration process.
• 📝 Prepare containers for waste and leftover samples, such as cuvettes and distilled water.
• 🚿 Clean the cuvette before use to avoid contamination.
• 🔬 Do not use latex gloves when handling the blank solution to prevent contamination.
• 📉 The absorbance reading should not show any yellow color, indicating a proper blank.
• 📋 Record the absorbance values for each concentration to compare and analyze results.

Q & A

What is the first step in preparing the samples for the spectrophotometer?

The first step is to prepare the standard solutions and samples with concentrations of 20, 40, 60, 80, and 100 ppm, and arrange them in order from the lowest to the highest concentration in the test tube rack.

Why should the spectrophotometer be warmed up before use?

The spectrophotometer needs to be warmed up for 15 minutes to ensure accurate readings and allow the machine to reach its operational temperature.

How should a cuvette be handled when using the spectrophotometer?

The cuvette should be held by the frosted side to avoid fingerprints on the clear part, which could interfere with the light passing through during measurement.

What is a blank solution, and why is it important in this procedure?

A blank solution, typically made using distilled water (aquades), is used to calibrate the spectrophotometer to zero absorbance before measuring the samples. This ensures that any readings taken are only from the sample and not from any other background interference.

What wavelength should be set on the spectrophotometer for this experiment?

The wavelength for this experiment should be set to 540 nm.

What action should be taken before inserting the cuvette into the spectrophotometer?

Before inserting the cuvette, you should clean it with a tissue, particularly the clear sides, to ensure there are no residues or fingerprints that could affect the measurement.

How should the cuvette be filled, and how much solution is required?

The cuvette should be filled using a pipette with just enough solution to cover the required portion of the cuvette, usually a small amount relative to the size of the cuvette.

What should be done after calibrating the spectrophotometer with the blank solution?

After calibrating with the blank solution, the 'auto zero' button should be pressed. For subsequent measurements, auto-zero calibration does not need to be repeated.

What indicates that the solution has been measured correctly?

The absence of any noticeable color, such as yellow, in the solution during measurement indicates that it has been properly prepared and measured.

Why is it important to dry the cuvette after rinsing with distilled water?

It is important to dry the cuvette to prevent water droplets from affecting the spectrophotometric readings, which could introduce errors into the measurements.