# Preparing a Solution using ppm and ppb -

• Zghakt
In summary, to prepare a 50 ppb Pb standard solution in 1% HNO3 gravimetrically, 0.05 mL of a 50 ppm Pb stock solution should be mixed with 49.95 mL of HNO3. This method was chosen due to a conversion to mg/L being desired and the resulting dilution factor being 1000 times. Further clarification is needed on whether the 50g refers to the mass of the solution or solute.
Zghakt
I would like to prepare 50.0 g of 50 ppb Pb standard solution in 1% HNO3 gravimetrically, in a 50.0mL plastic tube from a stock solution of 50 ppm Pb.

From what I understand, this is a dilution...so C1V1 = C2V2

I like working in mg/L more than ppb and ppm so I converted

50 ppb = 0.05 mg/L
50 ppm = 50 mg/L

C1V1 = C2V2
50 mg/L V1 = (0.05 mg/L)(0.05L)
V1 = 0.00005L or 0.05 mL

so then 0.05 mL of 50 ppm Pb and 49.95 mL of HNO3.
Would this be the proper way to prepare this solution?

Zghakt said:
gravimetrically

Zghakt said:
0.05 mL of 50 ppm Pb and 49.95 mL of HNO3
"Gravimetrically?" Or, by volume? At this concentration, a significant fraction of solute is going to be adsorbed on the surfaces of vessels/flasks/containers; are you concerned, or have you made allowances for such an effect?

Bystander said:
"Gravimetrically?" Or, by volume? At this concentration, a significant fraction of solute is going to be adsorbed on the surfaces of vessels/flasks/containers; are you concerned, or have you made allowances for such an effect?

This is my first time preparing a solution given the above directions. My instructions stated to prepare the solution gravimetrically. However, I could only figure out how to prepare the solution by volume, ie: 0.05 mL of 50 ppm Pb and 49.95 mL of HNO3. Would you suggest there is a more effective way to make the solution?

Zghakt said:
I would like to prepare 50.0 g of 50 ppb Pb standard solution in 1% HNO3 gravimetrically, in a 50.0mL plastic tube from a stock solution of 50 ppm Pb.

From what I understand, this is a dilution...so C1V1 = C2V2

I like working in mg/L more than ppb and ppm so I converted

50 ppb = 0.05 mg/L
50 ppm = 50 mg/L

C1V1 = C2V2
50 mg/L V1 = (0.05 mg/L)(0.05L)
V1 = 0.00005L or 0.05 mL

so then 0.05 mL of 50 ppm Pb and 49.95 mL of HNO3.
Would this be the proper way to prepare this solution?

I doubt you do want to prepare 50 g at 50 ppb - that would be a billion liters wouldn't it?

You had better state or find out what you mean by a billion as there are two different meanings round.

If it is thousand million then you have tondilut your 50 ppm a thousand times. Burt I'm not sure you knows what this means.

Last edited by a moderator:
epenguin said:
I doubt you do want to prepare 50 g at 50 ppb - that would be a billion liters wouldn't it?

I suppose 50 g refers to the mass of the solution, not of the solute.

I misread and thought it was saying 50g of Pb! He also says 50 ml. For his practical purposes I guess it is good enough to. Insider these two the same thing.

epenguin said:
I misread and thought it was saying 50g of Pb! He also says 50 ml. For his practical purposes I guess it is good enough to. Insider these two the same thing.

Okay, does this mean the original calculations I posted (see first post) would be correct to prepare the solution then? I can clarify with the person who wrote the directions by what the 50g refers too (either solute or solution)

## 1. What is a ppm and ppb?

A ppm stands for parts per million, which is a unit of measurement used to express the concentration of a solution. It represents the number of parts of a solute per one million parts of the solution. Similarly, ppb stands for parts per billion, which is a unit of measurement used for even smaller concentrations.

## 2. How do you prepare a solution using ppm and ppb?

To prepare a solution using ppm and ppb, you first need to determine the desired concentration of the solution in either ppm or ppb. Then, you can use the formula C = (m/M)V, where C is the concentration in ppm or ppb, m is the mass of the solute, M is the molar mass of the solute, and V is the volume of the solution in liters. This formula will help you calculate the amount of solute needed to make the desired solution.

## 3. Can you convert between ppm and ppb?

Yes, you can convert between ppm and ppb by using the conversion factor of 1000. This means that 1 ppm is equal to 1000 ppb, and 1 ppb is equal to 0.001 ppm. So, to convert from ppm to ppb, you multiply the ppm value by 1000, and to convert from ppb to ppm, you divide the ppb value by 1000.

## 4. What are some common uses of ppm and ppb measurements?

PPM and ppb measurements are commonly used in various scientific fields, such as chemistry, biology, and environmental science. They are used to measure the concentration of substances in solutions, such as pollutants in water or chemicals in a sample. They are also used in quality control to ensure the accuracy of products, such as in the food and beverage industry.

## 5. Are there any safety precautions to consider when working with ppm and ppb solutions?

Yes, there are safety precautions to consider when working with ppm and ppb solutions. Always wear appropriate personal protective equipment, such as gloves and goggles, when handling potentially hazardous substances. Also, be sure to carefully measure and mix the solutions to avoid any spills or accidents. It is important to follow proper handling and disposal procedures to prevent any harm to yourself or the environment.

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