Table I.

Summary of chromatography assay. All of the chromatography assay was performed using a model ALC 717 chromatograph (Waters Associates, Milford, Massachusetts). The concentrations of antibiotics in the cement cylinders were obtained from the high-performance liquid chromatography (HPLC) analysis through comparisons made with the prepared daily standard curves where related the peak areas with antibiotic concentrations

Antibiotic	Column (dimensions)		Particle size		Mobile phase		Detection sensitivity (µg/ml)
Vancomycin	RP18 (100 mm × 4.6 mm)		5 μm		Water/Acetonitrile/100 mM ammonium formate (78/12/10)		0.5
Teicoplanin	C18 (250 mm × 4.6 mm)		5 μm		Sodium dihydrogen phosphate/Acetonitrile (90/10)		0.25
Imipenem	Atlantis T3 (150 mm × 4.6 mm)		5 μm		Water/Methanol (93/7)		0.5
Ceftazidime	Atlantis T3 (150 mm × 4.6 mm)		5 μm		Acetonitrile/25 mM KH2PO4-Na2HPO4 (10/90)		0.25
Piperacillin	Atlantis T3 (150 mm × 4.6 mm)		5 μm		Acetonitrile/0.05 M phosphate buffer (50/50)		0.5
Gentamicin	C18 (300 mm × 3.9 mm)		5 μm		Acetonitrile/0.05% aqueous trifluoroacetic acid (70/30)		0.2
Tobramycin	C18 (300 mm × 3.9 mm)		5 μm		Water/Acetonitrile (6/94)		0.2