Determination of lycopene, alpha-carotene and beta-carotene in serum by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry with selected-ion monitoring.
A selected-ion monitoring (SIM) determination of serum lycopene, alpha-carotene and beta-carotene by an atmospheric pressure chemical ionization mass spectrometry (APCI-MS) was developed. A large amount of serum cholesterols disturbed the SIM determination of carotenoids by contaminating the segment of interface with the LC-MS. Therefore, separation of carotenoids from the cholesterols was performed using a mixed solution of methanol and acetonitrile (70:30) as the mobile phase on a C18 column of mightsil ODS-5 (75 mm x 4.6 mm I.D.). The SIM determination was carried out by introducing only the peak portions of carotenoids and I.S. (squalene) by means of an auto switching valve. In the positive mode of APCI-MS, lycopene, alpha-carotene and beta-carotene were monitored at m/z 537 and I.S. was monitored at m/z 411. This method was linear for all analytes in the range of 15-150 ng for lycopene, 7-70 ng for alpha-carotene and 25-50 ng for beta-carotene. The detection limit of LC-APCI-MS-SIM for carotenoids was about 3 ng per 1 ml of serum (S/N = 3). The repeatabilities, expressed as C.V.s, were 10%, 8.4% and 5.3% for lycopene, alpha-carotene and beta-carotene, respectively. The intermediate precisions, expressed as C.V.s, were 11.2%, 8.8% and 6.5% for lycopene, alpha-carotene and beta-carotene, respectively.
Hagiwara
T
T
The Tokyo Metropolitan Research Laboratory of Public Health, Japan.
Yasuno
T
T
Funayama
K
K
Suzuki
S
S
D001274:Atmospheric Pressure; D002338:Carotenoids / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D000077276:Lycopene; D013058:Mass Spectrometry / Q000379:methods*; D012015:Reference Standards; D015203:Reproducibility of Results; D013185:Squalene / Q000737:chemistry; D019207:beta Carotene / Q000097:blood*
D019207:beta Carotene; D002338:Carotenoids; C041635:alpha-carotene; D013185:Squalene; D000077276:Lycopene