1. LC with MS detection is perhaps the most reliable means for confirmation of analyte‘s identity. Please rank the following identity confirmation situations according to reliability (1 is the most reliable). The European Commission implementing regulation 2021/808 can be used as guidance.
| LC retention time (k > 1) and a single MS/MS transition |
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| LC retention time on two different columns (both have k > 1) and a single MS/MS transition (same transitions for both columns). |
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| LC retention time (k > 1) and MS/MS with a single precursor ion with two product ions |
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| LC retention time (k > 1), MS/MS with two transitions, of which one of the product ions is detected with HRMS |
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