Internal Standards for Quantitative Analysis of Chemical Warfare Agents by the GC/MS Method: Nerve Agents

Table 9

Assessment of CWA determination accuracy and precision testing (c_ISTD—internal standard concentration, t—t criterion value, S_R—relative standard deviation, number of measurements n = 5, and t_CRIT = 2.776).

CWA/Internal standard	cISTD (mg/L)	Known CWA concentration (mg/L)	GC/MS system	Determined concentration (mg/L)	t	SR (%)
Tabun/heptan-1-ol	30.0	32.7	7890A/5975C	29.9	2.147	4.0
			EM 640	31.6	1.152	11.1
	4.0	3.4	Intuvo 9000/5977B	3.6	1.263	2.2
Sarin/triethyl-phosphate	20.0	14.5	7890A/5975C	14.5	0.049	3.8
			EM 640	13.3	1.792	14.7
	5.0	9.1	Intuvo 9000/5977B	9.7	2.046	6.0
Soman/triethyl-phosphate	20.0	19.5	7890A/5975C	18.3	0.311	5.6
			EM 640	19.0	0.745	4.2
	12.0	7.0	7890A/5975C	7.5	1.538	5.4
			Intuvo 9000/5977B	6.7	1.147	3.7
			EM 640	7.1	0.297	9.3
Cyclosarin/triethyl-phosphate	25.0	21.0	7890A/5975C	20.3	0.459	5.6
			EM 640	20.7	0.612	4.2
	12.0	8.8	7890A/5975C	9.5	2.005	5.4
			Intuvo 9000/5977B	7.9	1.916	3.7
			EM 640	8.9	0.309	9.3
	5.0	3.7	Intuvo 9000/5977B	4.0	1.714	6.0
VX agent/di-n-hexylamine	15.0	17.7	7890A/5975C	17.0	0.699	5.6
			Intuvo 9000/5977B	16.7	1.015	4.9
			EM 640	15.3	1.973	8.4
	10.0	19.3	7890A/5975C	17.6	1.514	6.8
			Intuvo 9000/5977B	18.0	1.865	9.0
Edemo/tri-n-butylphosphate	10.0	11.0	7890A/5975C	10.3	1.052	7.4
			Intuvo 9000/5977B	11.2	0.328	3.9
	27.0	22.2	7890A/5975C	23.6	0.874	5.8
			EM 640	22.3	0.079	6.5
	8.0	6.1	Intuvo 9000/5977B	5.9	1.232	6.6
Medemo/di-n-amylether	40.0	35.0	7890A/5975C	35.8	1.051	4.8
			EM 640	36.2	0.782	12.3
	10.0	6.5	Intuvo 9000/5977B	6.9	0.429	5.1