09
Jul
2019

The Definition of Analytical Chemistry

July 9th, 2019 in Learning

So, I asked Pat what his definition of analytical chemistry was. In clear, methodical Pat Pond fashion, he proceeded:

1. There are two main kinds of analytical chemistry

a. Organic

i. we do this one

b. Inorganic

2. As chemists, we choose one of 3 things to happen to a chemical compound we’re interested in:

a. Cause compound to emit something

b. Cause compound to absorb something

c. Cause compound to react with something

i. Reactions are important for GC-MS in EI and CI

3. After choosing one of 2a, 2b, or 2c, we commit to doing it consistently. Consistency is ensured by

a. Daily checks of instrumentation

i. Calibration verification (a.k.a. “calver”)

ii. Analysis of spikes and blanks

b. SOPs for experimentation

i. These control what is done from sample reception to chromatogram analysis

ii. Must be followed

4. Consistency ensures

a. Reproducibility

b. Precision

i. Which is controlled by SOPs

5. Accuracy of results is determined by

a. External comparison against other known values

i. Performance evaluations – 2 per year (per matrix), minimum

ii. Interlaboratory comparisons and comparison against consensus values

b. Analysis of standard materials from a second source

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I took a quick breath. It all seemed a little complicated.
“You’re thinking too much again,” Pat said with a smile.

~ Filtered by Dave Hope ~

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