Serial dilution lab

Multiple Dilutions. Larger Dilutions. Are you stuck with a problem? Ask Question. Get involved! Remember Me. Register Forgot Password Resend activation code.

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Cancel Delete. Are you sure you want to delete your Profile? This will remove all of your posts, saved information and delete your account. This cannot be undone. Cancel Delete My Profile. Public Site Members. Cancel Share. Written by Sourav Bio. If I had 2 ml of a substance and then added 4 ml of a dilution, what would my ratio be?

Not Helpful 2 Helpful 7. Include your email address to get a message when this question is answered. By using this service, some information may be shared with YouTube. You Might Also Like How to. How to. About This Article. Co-authored by:. Co-authors: Updated: November 30, Categories: Chemistry. Article Summary X To do serial dilutions, start by filling several test tubes with 9 milliliters of a dilution liquid, like water.

Italiano: Eseguire il Metodo delle Diluizioni Seriali. Nederlands: Een scheikundige verdunningsreeks maken. Bahasa Indonesia: Melakukan Pengenceran Berantai. Thanks to all authors for creating a page that has been read , times. I wasn't sure how the math worked out when my teacher introduced it, but now I feel like I have a solid foundation on which to build my experiment.

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Katan Ali Oct 8, Anonymous Oct 20, Sodium Acetate Buffer solutions are inexpensive and ideal to practice your skills. Your accuracy can be verified by taking a pH reading. In this part of the lab, we will be preparing solutions of known concentrations. These then will be used to create a standard curve. Standard curves also known as calibration curves represent the relationship between two quantities. The standard curve will be used in part 3 of the lab to determine the concentrations of unknown solutions of methylene blue.

Prepare 40 mL of 5. Complete Data Table 1. Put in your notebook. Serial dilutions are quick way of making a set of solutions of decreasing concentrations.

In this part of the lab we will make a series of dilutions starting with the Methylene Blue solution prepared in part 2 of this lab. Then, we will us the spectrophotometer to determine the absorbance of each solution.

Once we know the absorbance, we will use the equation from your standard curve prepared in part 2, to determine the actual concentrations of each of your solutions.

Using the remainder of your 5. In your notebook, draw a diagram showing the serial dilutions for the 6 methylene blue solutions you are preparing. In the diagram, indicate the volume being withdrawn from the concentrated solution, the volume of water added, the concentration of the new solution, and the total volume.

Continue with this process to make the , , and serial dilutions. Use the equation from your standard curve in part 2 and the absorbance values of your solutions from Part 3, to determine the actual concentration of your solutions. Introduction A Serial dilution is a series of dilutions, with the dilution factor staying the same for each step. A ten-fold serial dilution, which can also be called a dilution, or a series with dilution factor of To determine the concentration at each step of the series, you divide the previous concentration by the dilution factor.

The ending volume in the last tube would be mL Key considerations when making solutions: Make sure to always research the precautions to use when working with specific chemicals. Be sure you are using the right form of the chemical for the calculations. Some chemicals come as hydrates, meaning that those compounds contain chemically bound water. Be sure to pay attention to which one you are using.

For example, anhydrous CaCl 2 has a MW of Always use a graduate cylinder to measure out the amount of water for a solution, use the smallest size of graduated cylinder that will accommodate the entire solution. For example, if you need to make 50 mL of a solution, it is preferable to use a 50 mL graduate cylinder, but a mL cylinder can be used if necessary.

If using a magnetic stir bar, be sure that it is clean. Do not handle the magnetic stir bar with your bare hands. In the back row are the test tubes and plastic petri dishes. Obtain five test tubes and fill each with 9 mL of white seed beads diluent using the plastic beaker.

For this exercise, 9 mL will be represented by filling the plastic beaker to just below the mL mark. For this exercise, 1 mL will be represented by covering the bottom of the plastic beaker with the seed beads. Shake the test tube well to mix the beads. Notice the distribution of green beads mixed in with the white beads.

Be sure to mix your beads until they are evenly distributed. Notice that there are fewer green beads in the test tube. Count the number of virus particles green beads in each dish and record your data in Table 1. Use the tweezers to remove the green beads and place them into your beaker as you count them. Remember, the best plate to use is one that contains between 30 and virus particles green beads.

Record your results in the table and calculate the number of virus particles in your original sample. Diagram a series of twofold, fivefold, and tenfold dilutions using four tubes. For each of the dilution series, calculate the number of virus particles in your sample if after making the dilutions you plated 1 mL from the fourth tube and then after incubation you counted 50 plaques on the fourth dilution plate.

You can experiment with alternatives to seed beads, but I found that the seed beads gave the best visualization results. Some alternatives to seed beads include white and brown rice, larger beads, or glow-in-the-dark beads. You can make up numerous dilution problems as a homework assignment.

To follow up the dry lab, I have students serially dilute Methylene Blue, measure the absorbance of their samples at nm, and see how close they have come to a set of dilution tubes I have made.

Also, as a follow-up, I will have students look for a journal article in which the researchers have used serial dilutions in their work and ask them to explain why the serial dilutions were beneficial to the experiment. I usually have the students do this as homework, but you might consider having examples in the lab for them to look through and have a group discussion.

This is a good way to see if the students have grasped the concept of serial dilutions. Two examples of journal articles that can be used are provided in the References below El-Shibiny et al. Finally, depending on the course, students can apply what they learned to enumerate bacteria from food or milk. I developed this laboratory for use in an upper-level undergraduate virology course.

I used this exercise on the first day of class to introduce the students to a technique that they would be using throughout the semester. Before and after the lab, I gave a short assessment survey to the students. Most students were more comfortable performing a serial dilution and more comfortable calculating the results after the lab. None of the students felt that the lab did not help at all.