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A Critical View on the Phenol Index as a Measure of Phenol Compounds Content in Waters. Application of a Biosensor

Kochana J., Adamski J., Parczewski A.

Ecological Chemistry and Engineering. S

2012

Vol. 19, nr 3

383-391

Phenol index is considered as an important indicator of water purity and quality. Usually phenol index is determined by a spectrophotometric method the calibration being based on phenol standards. Unfortunately, the absorptivities of different phenols compounds differ from each other. This leads to significant uncertainty concerning content of phenols in water. It is shown that the same shortage of the phenol index appears also if it is determined using an amperometric biosensor based on tyrosinase. The sensitivity of the biosensor response to four phenol compounds: phenol, catechol, 3-cresol and 4-chlorophenol was examined, as well as possible interactions between phenols, according to 24 factorial experiment. It was proved that individual phenols affect phenol index independently from each other, ie no significant interaction between phenols was detected. However, sensitivity of the biosensor to different phenols is not the same. Relationship between phenol index and concentrations of phenols in water is discussed.

Indeks fenolowy jest ważnym wskaźnikiem czystości i jakości wody. Oznacza się go zwykle metodami spektrofotometrycznymi z 4-aminoantypiryną, stosując fenol jako wzorzec. Ponieważ współczynniki absorpcji różnych związków fenolowych różnią się, wyznaczona wartość indeksu fenolowego obarczona jest znaczną niepewnością. Podobny efekt występuje, gdy indeks fenolowy oznaczany jest przy użyciu biosensora amperometrycznego opartego na tyrozynazie. W pracy wyznaczono czułości biosensora w stosunku do czterech związków fenolowych: fenolu, katecholu, 3-krezolu oraz 4-chlorofenolu oraz zbadano możliwe interakcje pomiędzy fenolami. Doświadczenia prowadzono według planów czynnikowych 24. Wykazano, że poszczególne fenole wpływają na indeks fenolowy niezależnie od siebie, tzn. nie stwierdzono istotnych interakcji pomiędzy fenolami. Jednak czułość biosensora jest różna w stosunku do różnych fenoli. Przedyskutowano zależność pomiędzy indeksem fenolowym a stężeniami fenoli w wodzie.

Wykorzystanie ciągłej analizy przepływowej z segmentowaniem strumienia (SFA) oraz detekcją spektrofotometryczną w oznaczaniu indeksu fenolowego w próbkach środowiskowych

Strugała-Wilczek A., Mitko K., Bebek M.

Przegląd Geologiczny

2009

Vol. 57, nr 12

1096-1100

Phenols belong to the most important contaminants that are present in natural environment due to many industrial processes (e.g. petrochemical, paper, plastics, dyes and pesticides by-products). Phenol compounds can have an important physiological influence on living organisms, in high concentrations even becoming the cause of acute poisoning or death (according to Paracelsus’ statement that Dosis facit venenum). Because of high toxicity, some of them have been included into the national priority lists of pollutants and required to be determined. In this paper, segmented flow analyzer with photometric detector has been tested for the possibility to determine phenol index determination in water and wastewater environmental samples with complex composition in a precise and safe way. Some validation parameters of established method (fixed under evaluated analytical parameters including e.g. optimized measurement conditions and appropriate sample pre-treatment) were presented. Linearity, limit of detection, precision and accuracy of presented procedure was determined. Finally, the proposed method was applied to the analysis of real samples of water and sewage that were examined due to its contamination with phenols and matrix differentiation. The described full automatic method may be used to determine total content of phenols, called as phenol index. It shows low detection limit, high accuracy and good correctness. Proposed continuous flow system comply with requirements and, therefore, it may be applied in monitoring studies as well as in the routine analysis of real samples of water and wastewater from different sources.