Methyl Esterification Combined with Gas Chromatography-Mass Spectrometry (GC-MS) for Determining the Contents of Lubricant to Evaluate the Compatibility of Chlorinated Butyl Rubber Stoppers with Liposome Injections

Table 1

Recoveries of methyl hexadecanoate and methyl stearate in chlorinated butyl rubber stoppers.

Analyte	No.	Spiked (mg)	Sample (mg)	Detected (mg)	Founded (mg)	Recovery (%)	Average recovery (%)	RSD (%)
Methyl hexadecanoate	1-1	0.7960	2.0481	2.7907	0.7426	93.29	97.33	2.55
	1-2	0.7936	2.0482	2.8083	0.7601	95.78
	1-3	0.7975	2.0483	2.8039	0.7556	94.74
	2-1	0.9950	2.0480	3.0122	0.9642	96.90
	2-2	0.9920	2.0480	3.0159	0.9679	97.57
	2-3	0.9969	2.0481	3.0313	0.9832	98.63
	3-1	1.1939	2.0478	3.2462	1.1985	100.38
	3-2	1.1904	2.0484	3.2131	1.1647	97.84
	3-3	1.1963	2.0482	3.2547	1.2065	100.85
Methyl stearate	1-1	1.4285	2.6063	3.9752	1.3689	95.83	96.55	1.29
	1-2	1.4370	2.6064	4.0012	1.3949	97.07
	1-3	1.4299	2.6065	3.9971	1.3906	97.25
	2-1	1.7856	2.6061	4.3496	1.7435	97.64
	2-2	1.7963	2.6061	4.3094	1.7033	94.82
	2-3	1.7874	2.6062	4.3377	1.7315	96.88
	3-1	2.1427	2.6058	4.6887	2.0829	97.21
	3-2	2.1555	2.6066	4.6410	2.0344	94.38
	3-3	2.1448	2.6063	4.7059	2.0996	97.89