The 1000 ng injection was established as the upper limit of quantitation for alprazolam. Two consecutive injections of the 1000 ng sample were made and immediately followed by a two blank injections. All traces of Alprazolam were removed using the unique and highly effective external needle flush (ENF) built into the 719D. Early work with tetracycline and miconozole established materials and ENF effectiveness.
| 1000 ng Sample | Run 95 |
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| 2nd 1000 ng Sample | Run 96 |
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| 1st Blank Injection | Run 97 |
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| 2nd Blank Injection | Run 98 |
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The autosampler ENF routine used in this analysis is accomplished in 13 seconds during the method run time. The ENF consists of solvent and mobile phase rinsing of the interior and exterior of the needle, the injection port, and needle seat in the injection valve. The two injection sequences shown below provide evidence that at least two further 1:10 dilutions were possible before reaching the LLQ.
| 1.0 ng Injection | Run 85 |
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| Blank Injection | Run 86 |
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PREVIOUS | Early work with tetracycline and miconozole established materials and ENF effectiveness.
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