The way the spectral integrals are converted into meaningful, quantitative information in SMA is manually determined by you using the Formula Editor located in the “Experiment” panel. You have full control over the calculation method and you define how quantification is performed for a constituent by entering basic maths functions in the formula editor.
The equation editor includes advanced math functions (to get statistical analysis for example). You can find below an example where we calculated the purity based on four different multiplets for the same compound, API_1_x (x=1-4); using DMP as reference:
We can use the equation editor to calculate the concentration for each of these components:
C_API_1_x
Then we could get the ‘Average’ by using the formula below:
0.25*(C_API_1_1 +C_API_1_2+C_API_1_3+C_API_1_4)
And also the ´Standard deviation´ using this formula:
Math.sqrt(0.25*(Math.pow(C_API_1_ave–C_API_1_1,2)+Math.pow(C_API_1_ave–C_API_1_2,2 )+Math.pow(C_API_1_ave–C_API_1_3,2)+Math.pow(C_API_1_ave–C_API_1_4,2)))
Dr. Mark Dixon (Mestrelab) gave a webinar on how identification and/or quantification of components of a mixture in solution is a common problem that a chemist must solve on a frequent basis.
Mnova offers multiple ways to address the analyses of mixtures when presented in NMR spectra, whether they are targeted or untargeted, and whether they require component identification and/or quantification. The most suitable technique depends upon the application.
Checking for any inconsistencies in your results:
The alert set-up is an important SMA feature that can be configured to give you feed-back when it does not find the multiplets you specify and expect. We call these “Alerts”.
From the “Experiment” panel, you can configure SMA in terms of the alerts it may show.