• Application Note

Midazolam on Oasis MCX

Midazolam on Oasis MCX
  • Waters Corporation
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This is an Application Brief and does not contain a detailed Experimental section.

Abstract

This application brief demonstrates the analysis of midazolam on Oasis MCX.

Introduction

Midazolam is used to produce sleepiness or drowsiness and to relieve anxiety before surgery or certain procedures. In this example, the sample size was limited (less than 100 uL of plasma) and therefore the Oasis μElution plate was used.

Weak Base: pKa ~ 6.15 and therefore Oasis MCX was used.

Experimental

Test Conditions

Oasis MCX 96-Well μElution Plate

Condition:

200 μL MeOH

Equilibrate:

200 μL H2O

Load:

100 μL sample (50 μL plasma diluted 1:1 with 4% H3PO4)

Wash 1:

200 μL 2% HCOOH

Wash 2:

200 μL MeOH

Elute:

50 μL (25 μL x 2) 5% NH4OH in MeOH

Dilute:

100 μL H2O or 100 μL 2% FA in H2O to neutralize

Inject:

10 μL

Column:

SunFire C18 2.1 x 20 mm IS, 3.5 μm

Mobile phase A:

10 mM CH3COO-NH4+, pH 5.5

Mobile phase B:

MeOH with 10 mM CH3COO-NH4+, pH 5.5

Flow rate:

0.4 mL /min

Instrument:

2777 Sample Manager and 1525μ Binary HPLC Pump

Gradient

Time(min)

Profile

%A

%B

0.0

95

5

3.0

5

95

4.0

5

95

4.1

95

5

5.0

95

5

Quattro Premier

ESI- source temp:

150 °C

Desolvation temp:

350 °C

Cone gas flow:

50 L /Hr

Desolvation gas flow:

600 L /Hr

Collision cell:

2.2e-3 bar (Ar gas)

Midazolam

MRM Transition

Cone (V)

CID (eV)

m/z 326.2 → 291.2

40

28

Results and Discussion

WA60087, June 2007

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