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pb070681 ☆ 2007-10-16 10:26 (6822 d 13:36 ago) Posting: # 1195 Views: 8,100 |
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I am confuse about matrix effect for protein precipitation. Is it necessary to perform matrix effect for protein precipitation? What is procedure? Regards pramod |
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Helmut ★★★   Vienna, Austria, 2007-10-16 15:38 (6822 d 08:24 ago) @ pb070681 Posting: # 1202 Views: 7,086 |
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Dear pramod! ❝ I am confuse about matrix effect for protein precipitation. Is it necessary ❝ to perform matrix effect for protein precipitation? See this post, and use the Forum's search feature... Since protein precipitation is the less rigorous sample clean-up technique, the chances to experience a matrix effect are higher than with other techniques (liquid-liquid extraction, solid phase extraction). ❝ What is procedure? Check the Matrix Factor (MF): peak response in presence of matrix ionsMF ≈ 1: no matrix effectsMF < 1: ion suppressionMF > 1: ion enhancementYou should optimize your method to come as close as possible to a MF of 1 (different sources of plasma) in method development in order to avoid surprises in routine analysis. For a nice overview see here. — Dif-tor heh smusma 🖖🏼 Довге життя Україна! ![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png) Helmut Schütz ![[image]](https://static.bebac.at/img/CC by.png) The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
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Charl ● 2007-10-17 11:04 (6821 d 12:58 ago) @ Helmut Posting: # 1206 Views: 6,641 |
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Dear HS ❝ Check the Matrix Factor (MF): ❝ ❝ ❝ ❝ ❝ ❝ ❝ ❝ You should optimize your method to come as close as possible to a MF of 1 (different sources of plasma) in method development in order to avoid surprises in routine analysis extraction could be performed with high efficiency, some times you cant get 100% recovery, does that mean you have ion effect? or is it as simple as the extraction capacity is not high enough for 100% recovery ! regards Charl |
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Helmut ★★★ Vienna, Austria, 2007-10-17 13:03 (6821 d 10:59 ago) @ Charl Posting: # 1208 Views: 6,793 |
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Dear Charl ❝ extraction could be performed with high efficiency, some times you cant get 100% recovery, does that mean you have ion effect? ❝ or is it as simple as the extraction capacity is not high enough for 100% recovery ! The matrix effect (mainly in LC/MS-MS, but to a minor extent in fluorescence [quenching]) has nothing to do with recovery. It’s possible to get just 2% of response after sample preparation (for a method with 100% recovery) compared to a matrix-free dilution due to ion-suppression. — Dif-tor heh smusma 🖖🏼 Довге життя Україна! Helmut Schütz The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
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vpardhasaradhi ☆ 2007-10-18 14:48 (6820 d 09:14 ago) @ Charl Posting: # 1212 Views: 6,810 |
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Dear Charl, In Recovery experiment, we spike the blank biological matrix (example: plasma) and process (extraction) the sample for analysis. Now we compare the instrument response for the analyte in this 'spiked and extracted' sample with the instrument response for the analyte in the mobile phase. This gives us the recovery data. In matrix effect, we first process (extract) the blank biological matrix (plasma) and spike it with analyte after extraction. Now we compare the instrument response for the analyte in this 'extracted and spiked' sample with the instrument response to the analyte in the mobile phase. This gives us the matrix factor, when we use the discussed calculation. Hence, matrix effect in LC-MS/MS are determined independent of recovery experiment. By doing so, we are taking care that the matrix factor determination (by spiking after extraction) is not influenced by the recovery (spiking before extraction). For all the LC-MS/MS methods, matrix factor needs to be determined irrespective of whether the method involves Protein precipitation or Liquid-liquid extraction or solid phase extraction. With best regards, V.Pardhasaradhi |
Ing. Helmut Schütz