– Transfer line 260
C, ionization source 230
C, quadrupole
150
C.
– Ionization energy 70 eV (EI).
– Scan mode acquisition in the m/z range 35–250 (6.2 scans
per second) (see Note 11).
3.1.4 Compound
Identification
and Quantitation
1. Unequivocal compound identification is performed by both
mass spectrum similarity and retention time coelution. Check
the coincidence of both with those of pure standards injected
under the same chromatographic conditions.
2. Integrate the area of each peak from the extracted ion chromatogram with the compound specific m/z ion indicated in
Table 1 (see Note 12).
3. An external standard should be introduced in the analytical
sequence (i.e., each 8–10 samples) and integrated as any
other chromatogram for data normalization. An admixture of
all the samples analyzed in the experiment is preferable for this
purpose (see Note 13).
4. For data normalization, in each chromatogram divide the area
of each peak to that of the average area of the same peak in the
closest reference chromatograms before and after that particular chromatogram. The result is a relative quantification for
each compound (the ratio of its abundance in the sample
compared to that in the external standard).
3.2 Specific
Apocarotenoid Method
3.2.1 Sampling
Procedure
1. Take the ripe tomato fruit with great care not to produce any
physical damage (see Note 14).
2. Clean the fruit surface with deionized water and carefully dry
with a paper cloth.
3. Excise the pericarp, discarding all the other fruit tissues. Dry
smoothly the inner part of the pericarp with a paper cloth to
prevent contamination with seeds or locular tissue (see Note
15).
4. Cut the pericarp into pieces (depending on fruit size) and flash
freeze in liquid nitrogen (see Note 16).
5. Homogenize the samples with a cryogenic mill to produce a
fine powder. Take care to keep the sample frozen all the time.
6. Store at À80
C in either plastic or glass tubes until analysis (see
Note 9).
3.2.2 Sample
Preparation
1. Weigh 500 g of frozen pericarp powder in a 15 mL glass vial (see
Note 17).
2. Close the vial and incubate for 10 min at 37
C in a water bath.
Plant Volatile Apocarotenoids
171
C, ionization source 230
C, quadrupole
150
C.
– Ionization energy 70 eV (EI).
– Scan mode acquisition in the m/z range 35–250 (6.2 scans
per second) (see Note 11).
3.1.4 Compound
Identification
and Quantitation
1. Unequivocal compound identification is performed by both
mass spectrum similarity and retention time coelution. Check
the coincidence of both with those of pure standards injected
under the same chromatographic conditions.
2. Integrate the area of each peak from the extracted ion chromatogram with the compound specific m/z ion indicated in
Table 1 (see Note 12).
3. An external standard should be introduced in the analytical
sequence (i.e., each 8–10 samples) and integrated as any
other chromatogram for data normalization. An admixture of
all the samples analyzed in the experiment is preferable for this
purpose (see Note 13).
4. For data normalization, in each chromatogram divide the area
of each peak to that of the average area of the same peak in the
closest reference chromatograms before and after that particular chromatogram. The result is a relative quantification for
each compound (the ratio of its abundance in the sample
compared to that in the external standard).
3.2 Specific
Apocarotenoid Method
3.2.1 Sampling
Procedure
1. Take the ripe tomato fruit with great care not to produce any
physical damage (see Note 14).
2. Clean the fruit surface with deionized water and carefully dry
with a paper cloth.
3. Excise the pericarp, discarding all the other fruit tissues. Dry
smoothly the inner part of the pericarp with a paper cloth to
prevent contamination with seeds or locular tissue (see Note
15).
4. Cut the pericarp into pieces (depending on fruit size) and flash
freeze in liquid nitrogen (see Note 16).
5. Homogenize the samples with a cryogenic mill to produce a
fine powder. Take care to keep the sample frozen all the time.
6. Store at À80
C in either plastic or glass tubes until analysis (see
Note 9).
3.2.2 Sample
Preparation
1. Weigh 500 g of frozen pericarp powder in a 15 mL glass vial (see
Note 17).
2. Close the vial and incubate for 10 min at 37
C in a water bath.
Plant Volatile Apocarotenoids
171