0
1
2
3 min.
Figure4
Ultra IBD allows increased LC/MS sensitivity of cephaloridine in normal phase mode.
1
LC_0124
RestekCorporation • (800)356-1688 • (814)353-1300 •
to retain a compound such as cephaloridine in normal
phase mode using levels of organic solvents above 50%
in the mobile phase, will allow increased sensitivity by
LC/MS (Figure 4).
The IBD column also provides other chromatographic
benefits. The excellent peak shape for cephaloridine in both
the reverse and normal phase modes (Figure 5) increases
sensitivity and improves quantitation. Furthermore, the
retention of cephalosporin and cephaloridine is essentially
unaffected by the pH. This allows full control in the pH
range of 2 to 8 for optimum stabilization of the cephalospor-
ins and penicillins during analysis, provided hydrolysis is
not an issue. The IBD column has a unique blend of hydro-
phobic and polar character for better resolution of closely
related compounds.
Conclusion
Closely related compounds such as penicillins and cepha-
losporins may require more than one type of interaction for
optimum resolution of closely related components. The
Restek IBD phase provides those interactions using only
simple mobile phases. The excellent peak shape, resolution
enhancement, and wide pH make it the ideal choice for the
analysis of penicillin- and cephalosporin-based antibiotics
by HPLC or LC/MS.
Figure5
Ultra IBD shows excellent peak shape for cephaloridine in both normal and reverse phase modes.
1
0 1 2 3 4 5 6 7 8 9min.
LC_0101&LC_0102
2
Column:
Ultra IBD
Catalog #:
9175565
Dimensions:
150 x 4.6mm
Particle Size: 5µm
Pore Size:
100Å
Conditions:
Normal Phase:
Mobile Phase: acetonitrile: pH 4.0 20mM
ammonium phosphate (80:20, v/v)
Reverse Phase:
Mobile Phase: acetonitrile: pH 4.0 20mM
ammonium phosphate (20:80, v/v)
Flow:
1.2mL/min.
Temp.:
27°C
Det.:
UV @ 254nm
Peak List:
1.cephaloridine reverse phase
2.cephaloridine normal phase
Sample:
Inj.:
5µL
Conc.:
1mg/mL
Solvent:
acetonitrile:water (50:50)
Peak List:
1. cephaloridine
Sample:
Inj.:
5µL
Conc.:
5µg/mL
Solvent:
Mobile Phase
Column:
Ultra IBD
Catalog #:
9175552
Dimensions: 50 x 2.1mm
Particle Size: 5µm
Pore Size:
100Å
Conditions:
Mobile Phase:
5mM ammonium
acetate pH 7.4:
acetonitrile (20:80)
Flow:
0.2mL/min.
Temp.:
ambient
Det.:
PE/Sciex API 150 EX
Interface:
Turbo Ion Spray
Ion Mode:
Positive
Nebulizer:
8L/hour
Curtain Gas:
12L/Hour
Ion Spray Voltage: 4700.0v
Temp.:
350°C
Orifice:
+ 10.0v
Ring:
+ 25.0v
SIM monitoring:
416 ± 3dal.
