Determination of Methanol, Acetaldehyde, and Ethyl Acetate in Thousand Folds of Ethanol Sample by Headspace Gas Chromatography with Mass Spectrometry

Table 2

The results of validating the determination of acetaldehyde, methanol, ethyl acetate, and ethanol.

The validated values	Ethanol	Methanol	Acetaldehyde	Ethyl acetate
Linear range (mg/L)	5–2500	5–240	5–240	5–240
Linear relationship (r^2)	0.9999	0.9998	0.9998	0.9999
Limit of detection (mg/L)	0.55	0.63	0.52	0.51
Limit of quantification (mg/L)	1.83	2.09	1.72	1.70
Relative standard deviation (%RSD) at:
(1) Low concentration	50 mg/L: 2.11	5 mg/L: 2.53	5 mg/L: 2.78	5 mg/L: 2.15
(2) Middle concentration	800 mg/L: 0.98	80 mg/L: 1.43	80 mg/L: 2.13	80 mg/L: 2.38
(3) High concentration	2400 mg/L: 0.42	240 mg/L: 1.70	240 mg/L: 2.93	240 mg/L: 2.34
Reproducibility (%RSD) at:
(1) Low concentration	50 mg/L: 3.56	5 mg/L: 1.15	5 mg/L: 2.42	5 mg/L: 2.78
(2) Middle concentration	800 mg/L: 1.31	80 mg/L: 1.74	80 mg/L: 2.68	80 mg/L: 2.75
(3) High concentration	2400 mg/L: 1.00	240 mg/L: 1.78	240 mg/L: 1.32	240 mg/L: 2.94
Assay recovery (%H) at:
(1) Low concentration	50 mg/L: 94.14–104.11	5 mg/L: 96.28–103.25	5 mg/L: 95.89–106.15	5 mg/L: 97.68–101.95
(2) Middle concentration	800 mg/L: 98.42–101.43	40 mg/L: 98.94–103.88	80 mg/L: 95.49–103.35	80 mg/L: 98.8–104.72
(3) High concentration	2400 mg/L: 98.76–101.64	240 mg/L: 97.42–102.00	240 mg/L: 97.38–101.13	240 mg/L: 97.87–101.94