CONCENTARION FOR INTERNAL STANDARD

[pliva]

Dear all,
For choosing the concentration of internal standard, we always/usually choose the concentration corresponding to the CCS-7 of aqeous solution. what is the reason of choosing specially cc7 when we use cc1 to cc8. if i choose some other level will it affect my result.

[Peter Apps]

Please do not bombard us with incomprehensible algorithms - what is CCS-7 ?

Peter

[pliva]

Please do not bombard us with incomprehensible algorithms - what is CCS-7 ?

Peter

ccs7 means the 7th standard in the calibration curve for linearity.

[MIB_EO]

"if i choose some other level will it affect my result."

Yes.

Will is significantly change your result? Depends.

It would probably help to have some knowledge of what system you are running LCMS?
Are you talking about mass accuracy? or quantification of area / intensity?

For mass accuracy I find best results are obtained with an internal standard of similar intensity to the peak being analysed. If the intensity is close to your cc1 then your standard should be too. Wouldn't it be nice to know this beforehand! Generally a less intense standard compared to a more intense analyte works a bit better than vice versa.

[pliva]

"if i choose some other level will it affect my result."

Yes.

Will is significantly change your result? Depends.

It would probably help to have some knowledge of what system you are running LCMS?
Are you talking about mass accuracy? or quantification of area / intensity?

For mass accuracy I find best results are obtained with an internal standard of similar intensity to the peak being analysed. If the intensity is close to your cc1 then your standard should be too. Wouldn't it be nice to know this beforehand! Generally a less intense standard compared to a more intense analyte works a bit better than vice versa.

actually i an using sciex tripple quad with analyst software and i am talking about quantitatiopn of area not mass. is there any reference so that i can go through regarding the statistic part. to be very frank i am not statiscian but just want to know the reason. just simply following the seniors does not seems good. thank you.