Table 1.

MS/MS parameters used for the identification and quantitation of α-retinyl esters and retinyl esters.

No.	Retention time (min)	Compound identity	HPLC-PDA spectrum (nm)	HPLC-APCI(+)-MS/MS m/z parent ion > m/z daughter ion	APCI collision energies (volts)e	HPLC-ESI(+)-MS/MS m/z parent ion > m/z daughter ion	ESI collision energies (volts)e
1	12.8	α-Retinyl myristate	298,311a ,325	269.2 > 123.1b	27.5	496.6 > 145.0	17.5
2	13.2	Retinyl myristate	325a	269.2 > 239.1c,d, 145.1d	35.0, 25.0	496.6 > 197.0	40
3	13.2	α-Retinyl linoleate	298,311a ,325	269.2 > 123.1b	27.5	548.6 > 145.0	17.5
4	13.9	Retinyl linoleate	325a	269.2 > 239.1c,d , 145.1d	35.0, 25.0	548.6 > 197.0	40
5	15.4	α-Retinyl oleate	298,311a ,325	269.2 > 123.1b	27.5	550.6 > 145.0	17.5
6	15.9	Retinyl oleate	325a	269.2 > 239.1c,d , 145.1d	35.0, 25.0	550.6 > 197.0	40
7	16.9	α-Retinyl palmitate	298,311a ,325	269.2 > 123.1b	27.5	524.6 > 145.0	17.5
8	17.3	Retinyl palmitate	325a	269.2 > 239.1c,d , 145.1d	35.0, 25.0	524.6 > 197.0	40
9	21.0	α-Retinyl stearate	298,311a ,325	269.2 > 123.1b	27.5	552.6 > 145.0	17.5
10	21.6	Retinyl stearate	325a	269.2 > 239.1c,d , 145.1d	35.0, 25.0	552.6 > 197.0	40

^aDenotes λ_max

^bDaughter with the strongest transition for α-retinol derivatives, chosen for quantitation

^cDaughters unique to retinol derivatives only

^dDaughters chosen for quantitation of retinol derivatives

^eCollision energy used for each respective daughter follows the order in which they are listed in the previous column