Dear Sara Kuhl

To determine an element's mass percent in a compound, divide the element's mass in 1 mole of the compound by the compound's molar mass and multiply the result by 100.

Kind Regards

Qamar Ul Islam

In this case its not an element in a compound. Its a compound in a mixture. Tge mixture is my reference material.

• Sara Kuhl wrote: "I have generated my cal curve from a single standard by varying the injection volume."

If you used HPLC, please revise it to use the SAME injection VOLUME for each sample/standard. Doing so follows good chromatography fundamentals / practices (*Changing the volume may result in changes to the peak shape, area or even retention time). Injection Volume should not be a variable in sample analysis. Create standards with different concentrations, then inject the same volume of each one (levels) to create the calibration curve.

• Here is a link to a professional article that discusses HPLC calibration types and methods: "External (ESTD) vs. Internal Standard (ISTD) Calibration in HPLC"; https://hplctips.blogspot.com/2014/03/external-vs-internal-standard.html

Regarding your question of "Units". Use the units which are accurate and require the least conversion steps that are appropriate for the samples under analysis.

Some additional digging into the data has revealed some interesting behavior of these molecules during the separation. The initial question arose do the the fact that the HPLC quantitative results don’t match the NMR data we get, and this observation is reproducible for multiple experiments as well as the nature of the variability following a definite pattern.

After consulting here and other experts it has been defermined the calibration and calculations ARE correct, but the unexpected results are a product of the interesting behavior we have observed.

Dear Sara Kuhl kindly check..

https://www.convertunits.com/from/mg/ml/to/g/ml