Quantitation of Unknowns

Question

Hello, 
 
 We are trying to quantitate unknowns with MassHunter Quant using standards at relative retention times. The instructions I have seen for filling in the Amt. column for this say that we should input our dissolved solids into an extraction solution. I'm not sure this works for our applicaiton. 
 
 Basically what we do is. 
 1. Fill a plastic device with a known amount of liquid 200mL 
 2. let that sit then pour the liquid out into a beaker. 
 3. We create a calibration curve of standards, for instance 0.1 to 5ppm 
 4. We analyze the unknowns found from the extractions and quantitate by retention time. 
 
 We have been putting 200mL in the Tot Amnt line, a Dil of whatever dilution happened (for this lets assume no dilutions) then in the Amt. column we have been putting 1 because that seems to give us a reasonable answer to back calculate to the original amount of solution. 
 Does this seem correct to others? 
 
 Thanks for your help.

howard_sanford · Answer

Hello nthnpayne , 
 Dilution, Amt., and Total Amt. are used to calculate the Multiplier. The Multiplier is used to calculate a final concentration from the calculated concentration from the calibration curve. They work together as explained below. The examples given are not requirements for the fields but merely show how they could be used if necessary. You would need to determine if this calculation is appropriate for the work you are doing. 
 
 Multiplier 
 This column can be added in the Compound Method section of the batch table. It cannot be directly edited but displays the multiplier that has been calculated using Dilution, Sample Amount, and Total Sample Amount. 
 Multiplier = (Total Sample Amount / Sample Amount) *Dilution 
 Final Concentration = Calculated Concentration * Multiplier 
 By default, Dilution ( Dil. ) has a value of 1. Sample Amount ( Amt. ) and Total Sample Amount ( Tot. Amt. ) do not have values and are not used in the calculation unless both have a value entered. 
 Dilution (Dil.) 
 The simplest case is to use only Dilution. The column is labeled Dil. and can be added in the Sample section of the batch table. If there is no Sample Amount or Total Sample Amount entered, then the multiplier is simply the Dilution 
 Multiplier = Dilution 
 Example: If the sample is diluted by a factor of 2, the Dilution Factor is 2. Hence, the Calculated Concentration is multiplied by 2 to adjust the Final Concentration. 
 
 Sample Amount (Amt.) and Total Sample Amount (Tot. Amt.) 
 The columns are labeled Amt. and Tot. Amt. and can be added in the Sample section of the batch table. For these to be used in the calculation of the multiplier, both must have a value entered. If Dilution is 1 (default), then the multiplier is simply 
 Multiplier = Total Sample Amount / Sample Amount 
 Example: 
 If a lab needs to report the total amount of a target compound present in a 100 g sample but only 20 g of the sample needs to be processed for analysis, they could enter 100 for Tot. Amt. and 20 for Amt. so that the Calculated Concentration is multiplied by 5 to adjust the Final Concentration.