Benzene (99.8%), toluene
(99.7%), chlorobenzene (99.7%), benzonitrile (99%), butyrophenone
(99%), 1-phenyl-2-butanone (98%), 4-phenyl-2-butanone (98%), retinol
(95%), pseudoionone (>90%), 2,6-dimethyl-2,4,6-octatriene (80%),
tetracene
(98%), pentacene (99%), and chloroform (99.9%) were purchased from
Sigma-Aldrich (Vienna, Austria). Benzo[a]pyrene (99.6%)
was from LGC Standard. Methanol (99.9%) and acetonitrile (99.9%) were
purchased from Honeywell. For the solid analytes (PAHs and retinol),
solutions with concentrations of 50 μmol/L were prepared in
pure solvents, while for the liquid analytes (benzene derivatives
and ketones) the concentration of the measured solutions was 0.01%
v/v. The head space of the volatile analytes (benzene derivatives
and ketones) was injected into the ionization source as vapor samples.
A syringe pump (KD Scientific, series 100, USA) was used to inject
the solutions with flow rate of 20 μL min–1 into the nebulizer. A commercially available tune mix (ESI-L Low
Concentration Tuning Mix, G1969-85000, Agilent Technologies) was prepared
according to manufacturer instructions for tuning and accurate mass
calibration of the mass spectrometer.
(99.7%), chlorobenzene (99.7%), benzonitrile (99%), butyrophenone
(99%), 1-phenyl-2-butanone (98%), 4-phenyl-2-butanone (98%), retinol
(95%), pseudoionone (>90%), 2,6-dimethyl-2,4,6-octatriene (80%),
tetracene
(98%), pentacene (99%), and chloroform (99.9%) were purchased from
Sigma-Aldrich (Vienna, Austria). Benzo[a]pyrene (99.6%)
was from LGC Standard. Methanol (99.9%) and acetonitrile (99.9%) were
purchased from Honeywell. For the solid analytes (PAHs and retinol),
solutions with concentrations of 50 μmol/L were prepared in
pure solvents, while for the liquid analytes (benzene derivatives
and ketones) the concentration of the measured solutions was 0.01%
v/v. The head space of the volatile analytes (benzene derivatives
and ketones) was injected into the ionization source as vapor samples.
A syringe pump (KD Scientific, series 100, USA) was used to inject
the solutions with flow rate of 20 μL min–1 into the nebulizer. A commercially available tune mix (ESI-L Low
Concentration Tuning Mix, G1969-85000, Agilent Technologies) was prepared
according to manufacturer instructions for tuning and accurate mass
calibration of the mass spectrometer.