how to calculate the recovery of a spiked sample substracting the amount in the non-spiked sample

Question

I want to calculate the recovery of a spiked sample (sample type=spike) taking into account the amount present in the non-spiked sample (Sample type=sample, sample label=non-spiked). Both samples are in the same sequence. I guess I have to do a CC file Amount &ldquo;spiked-non-spiked&rdquo;, but I don&rsquo;t manage to do so. I am using Openlab CDS2.7. 
 Thank you in advanced 
 Oihana

sgamba · Accepted Answer

Here is one way, it can be modified as needed. 
 For the recovery I am using the formula: 
 %R = ((Spiked sample result - Unspiked sample result) x 100%) / Known spike added concentration 
 
 In the Project, I chose to make a Sample Custom Field to link the Sample and the Spike, type in the name of the Sample Name to link with the Spiked Sample, if the sample is not to be linked with a Spike, leave it blank. Using a Compound Custom Field for the Spike Concentration. If its a fixed concentration, this can be put in the formula below instead of using the customer field. 
 
 Create a Custom Calculation File. Used the Formula beow (change the names in the formula if needed to match the Sample and Compound Custom Parameters that were created in the Project): 
 IF(CurrentSample.GetCustomField("SpikeSample") <> &rdquo;&rdquo;, ( Compound_Amount - CurrentSequence.AllInjectionsBySampleName(CurrentSample.GetCustomField("SpikeSample")).First().AllPeaksAndGroupsByName( Compound_Name ).first(). Compound_Amount ) / CurrentPeakOrGroup .GetCustomField(&ldquo;SpikeConc&rdquo;) * 100, "") 
 
 In the Sequence or in the Injection List fill in the Sample name in the SpikeSample column to link the Spike to the Sample it corresponds to. Type in the Known Spike concentration in the Compounds Custom Field.

martin.adams · Answer

Oihana, 
 
 Try first . GetDoubleCC ( "p_p_SR" )) at the end of that expression in place of first()."p_p_SR") assuming your p_p_SR CC is a double type. 
 
 Marty

how to calculate the recovery of a spiked sample substracting the amount in the non-spiked sample

Top Replies