9.4
Organics
9.4.1
Hydrocarbons
Organics
221
Smith [631] classified large sets of hydrocarbon oil spectral data by computer into
'correlation sets' for individual classes of compounds. The correlation sets were then
used for determining the class to which an unknown compound belongs according to
its mass spectral parameters. A correlation set is constructed by use of ion series
representing the contribution to the total ionization of each of 14 ion series. The
technique is particularly valuable in the examination of results from coupled gas
chromatography-mass spectrometry of complex organic mixtures. For example, an
alkane fraction of lichen extract gave a spectrogram with 24 peaks (molecular weight
range 212-464), each of which was rapidly classified, generally unambiguously.
Dynamic headspace analysis of an aqueous sodium hydroxide homogenate has
been used to determine traces of hydrocarbons in marine algae [632].A combination
of gas chromatography and mass spectrometry was used to identify and determine
volatiles.
9.4.2
Phenols
Dallakyan et al. [633] have described a method for the determination oflow concentrations of phenols and substances containing sulphhydryl groups in microalgae
secretions. The method is based on the electrochemiluminescent oxidation ofluminol
(3-aminophthalic hydrazide) at 14-16 °C, pH 6.5, with a potassium iodide electrolyte
and a platinum electrode, to determine phenols and thiols. The inhibition of the
chemiluminescence, specific amongst substances studied to phenols and thiols, was
used as a means of measurement.
Of the substances examined, phenolic compounds possessed the strongest inhibitory properties, among them, monophenols - phenol and tyrosine - exhibited the
lowest inhibiting effect. The introduction of a second hydroxyl group on the benzene
ring (hydroquinone, pyrocatechol) increased the ability of the phenols to inhibit
luminescence. The inhibitory activity varied depending on the position of the hydroxyl groups. Phenols with an ortho-and para-arrangement of the hydroxyl groups
(hydroquinone, pyrocatechol, chlorogenic acid) inhibited luminescence more strongly than metaphenols (resorcinol). With some phenols - such as phenol, hydroquinone, pyrocatechol, and resorcinol - a direct connection was discovered between the
redox potential and the ability to inhibit chemiluminescence of luminol. Phenols
which contain three hydroxyl groups (propylgallate, gallic acid, pyrogallol) inhibit
luminescence more weakly than diphenols. Benzoic acid, which lacks the hydroxyl
group on the ring, did not influence luminescence. Of the complex phenols of plant
origin which were studied, an inhibitory effect was exhibited by tannin with a mean
molecular weight of 1700. Gossypol inhibited luminescence relatively weakly. This
method is of high sensitivity with a relative error varying from 1.5 to 6 %.
Organics
9.4.1
Hydrocarbons
Organics
221
Smith [631] classified large sets of hydrocarbon oil spectral data by computer into
'correlation sets' for individual classes of compounds. The correlation sets were then
used for determining the class to which an unknown compound belongs according to
its mass spectral parameters. A correlation set is constructed by use of ion series
representing the contribution to the total ionization of each of 14 ion series. The
technique is particularly valuable in the examination of results from coupled gas
chromatography-mass spectrometry of complex organic mixtures. For example, an
alkane fraction of lichen extract gave a spectrogram with 24 peaks (molecular weight
range 212-464), each of which was rapidly classified, generally unambiguously.
Dynamic headspace analysis of an aqueous sodium hydroxide homogenate has
been used to determine traces of hydrocarbons in marine algae [632].A combination
of gas chromatography and mass spectrometry was used to identify and determine
volatiles.
9.4.2
Phenols
Dallakyan et al. [633] have described a method for the determination oflow concentrations of phenols and substances containing sulphhydryl groups in microalgae
secretions. The method is based on the electrochemiluminescent oxidation ofluminol
(3-aminophthalic hydrazide) at 14-16 °C, pH 6.5, with a potassium iodide electrolyte
and a platinum electrode, to determine phenols and thiols. The inhibition of the
chemiluminescence, specific amongst substances studied to phenols and thiols, was
used as a means of measurement.
Of the substances examined, phenolic compounds possessed the strongest inhibitory properties, among them, monophenols - phenol and tyrosine - exhibited the
lowest inhibiting effect. The introduction of a second hydroxyl group on the benzene
ring (hydroquinone, pyrocatechol) increased the ability of the phenols to inhibit
luminescence. The inhibitory activity varied depending on the position of the hydroxyl groups. Phenols with an ortho-and para-arrangement of the hydroxyl groups
(hydroquinone, pyrocatechol, chlorogenic acid) inhibited luminescence more strongly than metaphenols (resorcinol). With some phenols - such as phenol, hydroquinone, pyrocatechol, and resorcinol - a direct connection was discovered between the
redox potential and the ability to inhibit chemiluminescence of luminol. Phenols
which contain three hydroxyl groups (propylgallate, gallic acid, pyrogallol) inhibit
luminescence more weakly than diphenols. Benzoic acid, which lacks the hydroxyl
group on the ring, did not influence luminescence. Of the complex phenols of plant
origin which were studied, an inhibitory effect was exhibited by tannin with a mean
molecular weight of 1700. Gossypol inhibited luminescence relatively weakly. This
method is of high sensitivity with a relative error varying from 1.5 to 6 %.