Liquid phase phenol analysis

Abstract

A liquid reagent composition for detecting phenol or phenol derivatives includes a reagent capable of generating a stained product by forming a bond with phenol, an oxidant compound or mixture of oxidant compounds, a basic compound or mixture of basic compounds. The ratio of [stained reagent]:[oxidant compound] is 1:2 to 50:1, having a pH greater than 7. Also disclosed is a kit for the use of the composition and liquid-phase method for analysing a fluid potentially containing phenol or a phenol derivatives.

Claims

1. A liquid reagent composition for detecting phenol or phenol derivatives comprising: a reagent capable of generating a stained product by forming a bond with phenol or a phenol derivative, an oxidant compound or mixture of oxidant compounds, a basic compound or mixture of basic compounds, wherein the ratio of [reagent capable of generating a stained product] : [oxidant compound or mixture of oxidant compounds] is 1:2 to 50:1 , and wherein the liquid reagent has a pH greater than 7.

2. The liquid reagent composition according to claim 1, wherein the reagent capable of generating a stained product is 4-aminoantipyrine (AAP) or a derivative of AAP having formula I ##STR00002## where: R1 is an alkyl radical containing 1 to 30 carbon atoms, linear or branched, or an aryl radical; R2 is a phenyl or para-aminophenyl radical; R3 is an alkyl radical containing 1 to 30 carbon atoms, linear or branched.

3. The liquid reagent composition according to claim 1, wherein the oxidant compound or oxidant compounds are selected from the group consisting of potassium persulphate, potassium peroxomonosulphate; hydrogen peroxide and potassium hexacyanoferrate.

4. The liquid reagent composition according to claim 1, wherein the basic compound or mixture of basic compounds comprising a buffer solution selected from the group consisting of phosphate, 2-amino-2-(hydroxymethyl)-1,3-propanediol, carbonate, glycine-sodium hydroxide, and borate buffer, to obtain a basic pH.

5. The liquid reagent composition according to claim 1, wherein the reagent capable of generating a stained product is AAP, the basic compound or mixture of basic compounds is chosen among a phosphate buffer or a borate buffer, and the oxidant compound or oxidant compounds is potassium hexacyanoferrate or a mixture of potassium hexacyanoferrate and one or a plurality of further oxidant compounds.

6. The liquid reagent composition according to claim 1, wherein the ratio of [reagent capable of generating a stained product] : [oxidant compound or mixture of oxidant compounds] is 1:2 to 10:1.

7. The liquid reagent composition according to claim 1, wherein the reagent capable of generating a stained product by forming a bond with phenol or a phenol derivative and the oxidant compound or mixture of oxidant compounds are present in quantities such that, after mixing, the concentrations of reagent capable of generating a stained product are equal to 1.0.10.sup.−3 M to 5.10.sup.−5 M.

8. The liquid reagent composition according to claim 1, wherein the reagent capable of generating a stained product by forming a bond with phenol or a phenol derivative and the oxidant compound or mixture of oxidant compounds are present in quantities such that, after mixing, the concentrations of oxidant are equal to: 2.0.10.sup.−3 M to 2.10.sup.−6 M.

9. The liquid reagent composition according to claim 1, wherein the reagent capable of generating a stained product is 4-aminoantipyrine (AAP) or a derivative of AAP having formula I ##STR00003## where: R1 is an alkyl radical containing 1 to 30 carbon atoms, linear or branched, or an aryl radical; R2 is a phenyl or para-aminophenyl radical; R3 is substituted phenyl.

Description

(1) The following examples illustrate the present application and the invention will be understood more clearly with reference to the appended drawings wherein

(2) FIG. 1 (FIG. 3) is a UV/Visible absorption tracking curve of the formation of a stained product by bubbling phenol contained in a liquid in a reagent composition according to the present invention;

(3) FIG. 2 (FIG. 4) represents a curve for tracking the progression of absorbance over time at 506 nm due to the formation of stained product by bubbling phenol contained in a liquid in a reagent composition according to the present invention over time;

(4) FIG. 3 (FIG. 6) is a UV/Visible absorption tracking curve of the formation of a stained product by bubbling phenol contained in a gas in a reagent composition according to the present invention;

(5) FIG. 4 (FIG. 7) represents a curve for tracking the progression of absorbance over time at 506 nm due to the formation of stained product by bubbling phenol contained in a gas in a reagent composition according to the present invention over time;

(6) FIG. 5 (FIG. 8) represents a calibration curve for the detection of phenol in a liquid;

(7) FIG. 6 represents a calibration curve for the detection of phenol in a gas.

(8) FIG. 7 represents an embodiment of a kit according to the invention.

EXAMPLE 1

Reagent Composition for Detecting Phenol or Phenol Derivatives

(9) 2.4 mL of a 0.016 M borate buffer solution at pH 9 is added into a pre-mixing vessel where the reagents are present in quantities such that, after mixing, the concentrations of reagent capable of generating a stained product AAP and of oxidant potassium hexacyanoferrate are both equal to 8.0.10.sup.−4 M.

(10) A ready-to-use liquid reagent composition suitable for use for assaying phenol or phenol derivatives is thus obtained. This reagent composition may produce in the presence of phenol or phenol derivative a stained quinoid compound having for phenol an absorption peak close to 510 nm. The composition has a pH equal to 9.

EXAMPLE 2

Reagent Composition for Detecting Phenol or Phenol Derivatives

(11) 2.4 mL of a 0.016 M borate buffer solution at pH 9 is added into a vessel where the reagents are present in quantities such that, after mixing, the concentrations of AAP and potassium hexacyanoferrate are both equal to 1.6.10.sup.−2 M and 8.0.10.sup.−4 M, respectively.

(12) A ready-to-use liquid reagent composition suitable for use for assaying phenol or phenol derivatives is thus obtained. This reagent composition may produce in the presence of phenol or phenol derivative a stained quinoid compound having for phenol an absorption peak close to 510 nm. The composition has a pH equal to 9.

EXAMPLE 3

Detection of Phenol and Phenol Derivatives in a Liquid Mixture

(13) 0.6 mL of 10.sup.−4 M phenol is added into a vessel containing the ready-to-use reagent for detecting phenol or phenol derivatives from example 1.

(14) UV-Visible absorption spectroscopy tracking over time makes it possible to observe the appearance of a peak at 506 nm, characteristic of the reaction product between the reagent capable of generating a stained product and phenol in the presence of the oxidant. The intensity of this peak increases as exposure progresses and then remains stable, meaning that phenol is progressively used up by the reaction, and that the quantity of quinoid stained product resulting from the reaction remains stable. The corresponding curve is shown in FIG. 1 (original FIG. 3). The stability of the staining obtained is also observed with the plateau in FIG. 2 (original 4). As such, the detection of phenol in a liquid mixture is possible, and may further be qualitative or quantitative.

EXAMLE 4

Detection of Phenol is a Gas Mixture

(15) A 100 mL/min continuous gas stream containing a fixed concentration of 950 ppb of phenol was bubbled in a vessel containing the ready-to-use reagent composition for detecting phenol or phenol derivative in example 2. The gas stream is supplied directly into the measuring vessel via a tube a few mm in diameter at the end whereof a syringe needle is fitted which is kept in the liquid. The needle is positioned such that the bubbles do not enter the optical path during measurement.

(16) A deuterium-halogen source (Ocean Optics, DH-2000-BAL) lights up the vessel and the absorption spectra are recorded by a UV-Visible spectrophotometer (Ocean Optics, QE65000). Absorbance tracking as a function of time makes it possible to observe the appearance of a peak at 506 nm, characteristic of the reaction product between the reagent capable of generating a stained product and phenol in the presence of the oxidant. The intensity of this peak increases as exposure progresses and then starts to stabilise, meaning that the probe molecule is progressively used up by the reaction. The results obtained are shown in FIGS. 3 and 4, respectively.

(17) This absorbance property of the solution may be correlated with the concentration of phenol by means of a calibration curve. With the absorbance is associated a change of colour of the solution visible to the naked eye. As such, the detection of phenol in a gas mixture is possible, and may further be qualitative or quantitative.

(18) Experiment 1: Calibration Curve of Phenol in a Liquid Mixture

(19) The same method as in example 3 was repeated for different phenol concentrations. The rate of formation of the stained reaction product between phenol and the reagents of the reagent composition of example 1 is dependent on the phenol concentration in solution. As such, plotting the value of the slopes as a function of the concentration gives the calibration curve for phenol detection. The calibration curve is reproduced in FIG. 5.

(20) Consequently, the slope obtained is correlated with the phenol concentration and it is possible using this curve to determine the concentration of a mixture containing an unknown quantity of phenol.

(21) Experiment 2: Calibration Curve of Phenol in a Gas Mixture

(22) The same method as in example 4 is repeated for different phenol concentrations. The rate of formation of the reaction product between phenol and the reagents is dependent on the phenol concentration in solution. As such, plotting the value of the slopes as a function of the concentration gives the calibration curve for phenol detection (FIG. 6).

(23) Consequently, the slope obtained is correlated with the phenol concentration and it is possible using this curve to determine the concentration of a mixture containing an unknown quantity of phenol.

EXAMPLE 4

Two-Compartment Kit

(24) FIG. 7 represents an embodiment of a kit according to the invention comprising a closed container provided with zones (optical windows) enabling optical detection by a suitable apparatus, and openings for the circulation or addition of liquids or gases.

(25) The container is equipped with a removable separation providing two juxtaposed compartments wherein are placed in one, the reagent capable of generating a stained product and in the other the oxidant compound, in solid form. The mixture of these two products can be made by removing the removable separation.

(26) It is possible to add a basic solution prepared in advance contained in a suitable container, in this case an ampoule, to the solid constituents and mix all the reagents, to obtain a ready-to-use solution.

(27) The detection of phenol or a phenol derivative in a liquid fluid may be performed for example directly via the openings of the container. Bubbling a gas mixture containing phenol is possible directly in the container.

(28) Detection may be performed directly by connecting an optical detection system to the optical windows of the container.