Characterization of Key Odorants in Soy Sauce and Their Concentration Changes during Storage

Table 2

Selected ions and response factors used in the quantitative analysis.

Nos.	Compounds	Ions (m/z)^a	Standard curves	R ^2b
		Analyte
1	Isobutanol	74	y = 0.1575x + 0.0866	0.9998
2	Butanol	56	y = 0.1706x − 1.9943	0.9971
3	3-methyl-1-butanol	70	y = 0.9393x + 3.2194	0.9983
4	Methylpyrazine	94	y = 7.8231x − 10.281	0.9900
5	Acetoin	88	y = 0.5428x − 0.2305	0.9967
6	Acetol	74	y = 0.1618x + 0.9311	0.9982
7	2,5-dimethylpyrazine	52	y = 0.2669x − 0.0073	0.9993
8	2,6-dimethylpyrazine	67	y = 0.3173x − 0.0159	0.9999
9	Ethyl lactate	75	y = 0.488x − 0.1911	0.9998
10	1-hydroxy-2-butanone	88	y = 0.0514x − 0.0001	0.9997
11	2-ethyl-6-methylpyrazine	122	y = 1.5858x + 0.0364	0.9998
12	2,3,5-trimethylpyrazine^c	84	y = 1.3559x + 11.665	0.9999
13	Acetic acid	60	y = 0.8918x − 1.337	0.9930
14	Methional^d	107	y = 10.167x + 3.195	0.9975
15	2-acetylfuran	110	y = 3.8914x − 2.3708	0.9941
16	Propionic acid	74	y = 1.695x − 3.3806	0.9930
17	Isobutyric acid	88	y = 0.2993x − 0.0962	0.9939
18	Phenylacetaldehyde	91	y = 2.8919x + 1.2293	0.9950
19	γ-butyrolactone	42	y = 1.2185x − 2.0827	0.9991
20	Furfuryl alcohol	98	y = 0.3202x + 12.562	0.9957
21	3-methylbutanoic acid	60	y = 0.9937x + 9.0398	0.9918
22	Methionol^e	109	y = 14.37x + 3.8688	0.9919
23	2(5H)-furanone	84	y = 2.0576x − 1.341	0.9910
24	3-methylvaleric acid	87	y = 0.4795x + 0.1068	0.9973
25	4-methylpentanoic acid	39	y = 0.6306x + 0.0381	0.9916
26	Methyl cyclopentenolone	112	y = 1.3368x + 0.7372	0.9982
27	Guaiacol	124	y = 3.4991x − 1.099	0.9984
28	Phenethyl alcohol	122	y = 1.1318x	0.9925
29	Maltol	126	y = 1.2064x + 30.159	0.9954
30	2-acetylpyrrole	94	y = 2.156x	0.9907
31	4-ethyl-2-methoxyphenol	152	y = 2.2447x + 0.1465	0.9970
32	HDMF	128	y = 0.1187x + 0.0159	0.9987
33	HEMF	142	y = 0.1525x − 0.3057	0.9906
34	4-ethylphenol	77	y = 1.1067x	0.9990
35	Sotolon	128	y = 0.3773x	0.9995
36	Phenylacetic acid	91	y = 3.1445x + 21.529	0.9960
37	Ethyl vanillate	196	y = 1.9382x − 0.1379	0.9994

^aSelected ions (m/z) used in quantitative analysis; ^bdetermination coefficient obtained through the linear least-squares method; ^c,d,ethe selected internal standards were [²H₃]-2,3,5-trimethylpyrazine, [²H₃]-methional and [²H₃]-methionol, respectively; and the internal standard of other compounds was 3-octanol. The selected ions of 3-octanol, [²H₃]-2,3,5-trimethylpyrazine, [²H₃]-methional, and [²H₃]-methionol were 83, 81,104 and 106, respectively.