Chromatography Forum

I am in the process of resurrecting a GC method from a former co-worker. The method uses 3-Pentanol as an IS. In the software, for the processing method, there is a data field for entering a value for the internal standard.
I have a 30,000 mg/L 3-Pentanol standard. The sample prep calls for 10uL of the IS to be added to 1.0 mL of each standard and each sample (total volume of every standard & sample = 1010 uL). The value I was told to enter in the software is 300. The units for the method are mg/L. It would seem to me that I should be entering the net mg/L of the IS in the samples & standards. The dilution factor for the samples is 1.01.
By my math, I am adding 0.3mg of sample in 10uL to 1.0 mL of sample, which gives a net of ~300 mg/L (corrected by the dilution factor). We are using OpenLab CDS, but I'm sure all chrom software computes the same way.

"I have a 30,000 mg/mL 3-Pentanol standard."

Then you are either an alchemist or a magician.

You need to study up on the SI units, their multipliers, and not using excessive trailing zeroes to express quantities.

"I have a 30,000 mg/mL 3-Pentanol standard."

Then you are either an alchemist or a magician.

You need to study up on the SI units, their multipliers, and not using excessive trailing zeroes to express quantities.

Ahh, thanks for the catch. I meant 30,000mg/L. We generally write it this way for the method. The rest of the analytes are prepared anywhere from 50mg/L to 2000 mg/L, and including the zeros is preferred.