Table 1.

Quality control and quality assurance measurements for pyrazine quantification

Pyrazine	CAS Number	Molecular Weight (g/mol)	LOD (µg/mL)	LOQ (µg/mL)	Repeatability (%RSD of n = 6)	%Recovery from liquids (n = 9)*	%Recovery from filters (n =9)*
Ethylpyrazine (EP)	13925–00-3	108.14	0.03	0.10	11.8	89 – 100	85–90
2,5-dimethylpyrazine (DMP)	123–32-0	108.14	0.04	0.12	7.4	76 – 98	85–92
2,3-diethylpyrazine (DEP)	15707–24-1	136.19	0.05	0.16	6.8	88 – 102	80–100
2,3,5-trimethylpyrazine (TMP)	14667–55-1	122.17	0.04	0.12	8.8	81 – 99	64–82
2,3,5,6-tetramethylpyrazine (TeMP)	1124–11-4	136.19	0.04	0.13	7.3	81 – 103	76–104
Acetylpyrazine (AcP)	22047–25-2	122.12	0.02	0.08	6.8	66 – 86	67–88

^*:Recoveries were estimated on three different concentrations, each repeated in triplicates.