How Can You Identify Incorrectly Prepared Standards in AA Analysis?

In summary, the standard calibration curve for atomic absorption spectroscopy is incorrect and has been made twice as concentrated. This can lead to problems when trying to solve a problem using molar absorption values from a textbook or a table, as it is difficult to prove anything "after the fact". There are safeguards in place to prevent such errors in a "regulated environment".
  • #1
Marcwhydothe
17
0
This is the problem:

You are doing a typical AA ( atomic absorption spectroscopy analysis)
What you don't know is that the standard calibration curve is incorrect you have made your concentration twice as concentrated.

For exable you believe that you have 2,4,6,8 ppm but actualy you have 4,8,12,16
The curve that you have is completely linear and pass at (C=0).
You are not allowed to go to you merk index or any table for that matter to check the molar absoptivity.

Now how can I look at the concentration I have written and look at my abs and know that I have made all of my standards incorrectly?
( remeber line is linear and passes through 0 line but all your standards are wrong twice as concentrated)

I was thinking you know your usualy A = epsilon*b*c
A1+A2+A3/C1+C2+C3 = A1/C1

But for some reason I I find something that works and I go to proove it and it doesn't work again. ( no matter what I am always reduced to solving the problem using molar absoptivity from a textbook or a table)

What other way is there to solve this problem I can feel the answer but for some unknown reason I can't seem to put it on paper.
I would greatly appreciate some help on this and if you can make diagrams that would be the best. Thx
 
Physics news on Phys.org
  • #2
If this is a routine analysis you are performing repeatedly the simplest way would be to qualitatively compare absorption values from previous sets of standards.

If you aren't allowed to consult literature the you have to fall back on your documentation.

I work in a "Regulated Environment" (GLP) and we have some safeguards in our systems designed to avoid such errors:

1. Primary STDs are prepared in duplicate and tested agaist each other to ensure replicate preparation accuracy.

2. A validated STD preparation plan is used and a preparation record is made contemporaneously with the preparation of each STD in the curve.

Without these records it is difficult to prove anything "after the fact".
 
  • #3
Oh darn it this question is messing me again it piss me off there not mathematical way to proove but hopefully by the early morning of tommorow ill have prooved withought a doudt that no matter what you do to the numbers or how dilute your solutions the only way is to check documentation, check tables for molar absorptivity or intuition since obviously the sample your anayzing for won't be on the graph that really then main one that usually gives it away for me lol.

Hey thanks for answering man really appreciate it !
If you need help with anything ill try to post some ideas
 

FAQ: How Can You Identify Incorrectly Prepared Standards in AA Analysis?

What is analytical chemistry?

Analytical chemistry is a branch of chemistry that focuses on the separation, identification, and quantification of chemical compounds in various substances. It involves the use of various techniques and instruments to analyze samples and provide information about their chemical composition.

What are some common analytical chemistry techniques?

Some common analytical chemistry techniques include chromatography, spectroscopy, titration, and mass spectrometry. These techniques use different principles and methods to separate and analyze chemical compounds in a sample.

Why is analytical chemistry important?

Analytical chemistry plays a critical role in various fields such as medicine, environmental science, and forensic science. It helps in identifying and quantifying substances, determining their purity, and understanding their properties. This information is crucial for developing new products, ensuring safety, and solving problems related to chemicals.

What are some common challenges in analytical chemistry?

Some common challenges in analytical chemistry include sample preparation, accuracy and precision of measurements, and interference from other compounds present in the sample. Instrumental errors and the availability of suitable standards for comparison can also pose challenges in obtaining reliable results.

How can analytical chemistry be used in everyday life?

Analytical chemistry has many applications in daily life, such as in food and drug testing, environmental monitoring, and quality control in industries. It is also used in consumer products, such as cosmetics and household cleaners, to ensure their safety and effectiveness. Additionally, analytical chemistry techniques are employed in medical diagnosis and research to understand diseases and develop treatments.

Similar threads

Replies
10
Views
4K
Back
Top