Spectrophotometric determination of phenol in the presence of congeners by multivariated calibration

Abstract

The generation of poly-hydroxilated transient species during the photochemical treatment of phenol usually impedes the spectrophotmetric monitoring of its degradation process. Frequently, the appearance of compounds such as pyrocatechol, hydroquinone and benzoquinone produces serious spectral interference, which hinder the use of the classical univariate calibration process. In this work, the use of multivariate calibration is proposed to permit the spectrophotometric determination of phenol in the presence of these intermediates. Using 20 synthetic mixtures containing phenol and the interferents, a calibration model was developed by using a partial least square regression process (PLSR) and processing the absorbance signal between 180 and 300 nm. The model was validated by using 3 synthetic mixtures. In this operation, typical errors lower than 3% were observed. Close correlation between the results obtained by liquid chromatography and the proposed method was also observed.

Spectrophotometric verification of biodegradation of phenol in a flow dynamic biocers-based bioreactor system

“…In the UV region absorbance, phenol has two broad peak bands between 200 and 235 nm, and again two peaks on a band at around 270-280 nm. These values correspond broadly with literature values for phenol absorbance at around 235 and 275 nm [33][34][35]. As the phenol concentration in the water decreased, the absorbance peaks in the former band shifts to even lower wavelengths ( Figure 5), which can be attributed probably to the decrease of the peak height at the higher wavelength.…”

“…With appropriate mathematical models applied to the analytical data, the model parameters can be obtained to estimate the concentration in the samples. Among those, linear regression, partial least squares regression and principal components regression have been used with success in complex determinations [34,[36][37][38][39].…”

Assessment of Phenolic Compounds in the Surface Waters of Godavari Canal, Andhra Pradesh, India

“…A number of analytical methods are reported for the determination of phenols, based on spectrophotometric, fluorimetric, kinetic, gas chromatographic, liquid chromatographic and enzyme and biosensors. Due to several characteristic features such as high sensitivity, operational facility and low cost the UV-visible spectroscopy is one of the most useful analytical techniques 9 .…”

Order of Photocatalytic Degradation as Ranked by Critical Photonic Times (CPTs) Indicates the Composition of Organic Dye Mixtures: Selectivity of Hydroxyl Radicals

“…After 1995, the development of robust numerical methods, [2] in particular the computercontrolled derivative spectrophotometry, [10][11][12][13][14] the H-point standard addition method [15,16] and multivariate calibration, [1,[17][18][19][20] have made spectrophotometric determination of analytes possible. It is, however, possible to chemometrically monitor the decolorization kinetics of one dye when a mixture of three dyes is treated by ozonation.…”