Welcome to the Sample Preparation forum!

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Dr. Analytical
Dr. Analytical's picture
Welcome to the Sample Preparation forum!

What is sample preparation?
It is the series of laboratory manipulations that we perform to "prepare" a sample for final analysis. Sample preparation can be as simple as a "dilute-and-shoot" procedure, or a lengthy combination of steps requiring multiple days to complete.

Why is sample preparation necessary?
* To get the original sample in a form that is appropriate for analysis (e.g., precipitate, liquid, gas, etc.)
* To remove interfering substances that would alter the analytical result or damage the instrument.
* To prepare the analytes for analysis (e.g., derivatization).
* To concentrate the sample to allow detection at very dilute concentrations.

Whatever issues you have with sample preparation, this is the place to discuss them! Share your secrets and successes, as well as your problems.

Ready To Learn
Ready To Learn's picture
Thank you for the information

Thank you for the information.

Please how do one go about preparing a blank sample e.g for aas analysis.

Thank you.

Dr. Analytical
Dr. Analytical's picture
When you say "aas" I am

When you say "aas" I am assuming you mean atomic absorption spectroscopy. If this is not correct, please provide more information.

A "blank sample" is usually defined as a solution that contains all of the solvents and reagents used to prepare your samples, but with no "sample" present.

For example, if you are digesting a solid sample for metals analysis (is this what you are doing?), you will add some acids (nitric, sulfuric, etc.) to your sample and heat it to dissolve the organic material and solubilize the metal. You should also process another sample using the same solutions, but no sample. Some people will call this a "process blank" or "method blank." Analyze this solution to show that you do not have interfering metals in the reagents and glassware.

You should also prepare a solution that contains the same reagents. Do not process this solution; just analyze it. This is called a "reagent blank."

If you have more questions, just write back.

Ready To Learn
Ready To Learn's picture
Thank you Dr. for the kind

Thank you Dr. for the kind explaination.

Dr. Analytical wrote:

When you say "aas" I am assuming you mean atomic absorption spectroscopy. If this is not correct, please provide more information.

A "blank sample" is usually defined as a solution that contains all of the solvents and reagents used to prepare your samples, but with no "sample" present.

For example, if you are digesting a solid sample for metals analysis (is this what you are doing?), you will add some acids (nitric, sulfuric, etc.) to your sample and heat it to dissolve the organic material and solubilize the metal. You should also process another sample using the same solutions, but no sample. Some people will call this a "process blank" or "method blank." Analyze this solution to show that you do not have interfering metals in the reagents and glassware.

You should also prepare a solution that contains the same reagents. Do not process this solution; just analyze it. This is called a "reagent blank."

If you have more questions, just write back.