Analytica OElsevier
Short
Chimica Acta, 84 (1976) 203-205 Scientific Publishing Company, Amsterdam
Communication - ________._. ___..-.-.---...
A SENSITIVE
K. L. BAJAJ**, Department (India) (Received
COLORIMETRIC
_._ ..-. ----
-
Printed
in The Netherlands
._. _ __
DETERMINATION
--_..
OF 2-PIIENYLPIIENOL*
I. R. MILLER and I. S. BHATIA
of Chemistry 23rd June
and Biochemistry.
Punjab
Agricultural
Uniwrsity,
Ludhiana
1975)
2-Phenylphenol is used [l] zs a fungicide citrus fruits and as a preservative for paints,
for the post-harvest
treatment
of
cosmetics and sizing materials [ 21. This communication describes a sensitive colorimctric method for the micro determination of Z-phenylphenol with 4-aminoantipyrine (4-aminophenazone) and chloramine-T which is more sensitive and accurate than the methods in which potassium hexacyanoferrate(II1) is used as the oxidizing agent [ 3-4 1.
Experimental Reagents and equipment. Solutions wcrc prepared from analytical-grade reagents. Organic solvents were distilled before use. Aqueous solutions were prepared from twice-distilled deionized water. For the stock 2-phenylphcnol solution (0.001 M), of 17 mg of 2-phcnylphenol was dissolved in 100 ml of dioxane. A Spectronic 20 Bausch and Lomb calorimeter with lo-mm cell was used.
Calibration curue. Take appropriate amounts of the stock solution of 2-phenylphenol (0.01, 0.02, 0.04, 0.06, 0.08, 0,l and 0.12 ml) in 25mlmeasuring flasks. Add 4 ml of aqueous 1 % (w/v) chloramine-T solution followed by 0.5 ml of aqueous 0.4 % (w/v) 4-aminoantipyrine solution and dilute to the mark with sodium carbonate-hydrogencarbonate buffer (pH 9.7). Prepare the blank similarly, without 2-phenylphcnol, and read the absorbance at 520 nm against the blank. The color is stable for at least 3 h. Results and discussion The reaction product of 4-aminoantipyrine with 2-phenylphenol in the presence of chloramine-‘I’ as oxidizing agent has a sharp absorption maximum at 520 nm. Beer’s law holds in the range 0.17-2.4 - 10m5 g of 2-phenylphenol -----. *Paper presented in the 43rd Annual Meeting of the Society of Biological (India). Ludhiana. November. 1974. **Present address: Tocklai Experimental Station, Jorhat-8, Assam, India.
Chemists.
204
per 25 ml of the final solution. When aliquots (0.06 ml) of the stock solution of 2-phenylphenol were treated with 2, 4, 6 and 8 ml of chloramine-T solution, the presence of excess of chloramine-T did not interfere with the absorbance, and 4 ml was used in subsequent determinations. Similarly, an excess of 4-aminoantipyrine did not affect the absorbance, and 0.5 ml of its solution was used subsequently. Since the reaction of 4-aminoantipyrine with phenolic compounds takes place at alkaline pH [5], aliquots (0.06 ml) of 2-phenylphenol solution were treated with carbonate-hydrogencarbonate buffers of pH 9.2,9.7, 10.2 and 10.7. No change in absorbance in this pH range was observed, and pH 9.7 was used subsequently, as recommended by previous workers [ 3-4 1. The results of replicate analyses (Table 1) show that the method is accurate and reproducible. TABLE
1
Reproducibility -_.-. --
of the determination of 2-phenylphenol --..-. --..-.-
Weight taken (pg) Mean value found (5 determinations) S.d. R.s.d. -_..-_-_-.
-.--
20.4 19.52
5.1 4.98
(JIM)
-...-._
0.0374 0.75 lo -..-.
---_
0.031 G 0.16 70 --
Percentage recovery from thin-layer chromatograms. T.1.c. is often used for the separation of 2-phenylphenol. The stock solution of 2-phenylphenol (10 ~1) was applied to an activated silica gel G plate, which was developed in chloroform-acetone (1: 1) and viewed under U.V. light to locate the 2-phenylphenol, which was eluted with dioxane. The solution was concentrated and the volume made up to 5 ml. For lo-~1 aliquots, the recovery was 99.7 f 1.5 (4 determinations). Determination of 2-phenylphenol in urine. A known volume of a concentrated ethyl acetate extract of rat urine was subjected to t.1.c. as described above. The concentration of 2-phenylphenol found by this method in 0.1 ml of the cluate was 18.8 pg; when hexacyanoferratc(II1) was used as an oxidizing 510 nm) a value of i6.6 pg was obtained. agent (A,,, Sensitivity and interferences. The minimum quantity of 2-phenylphcnol detected by this method was 6.8 - 10s8 g ml-‘, hence the method is more sensitive than those employing [ 3, 41 potassium hesacyanoferrate( III) as osidant.This method is also more convenient than that recently proposed by Rajzman [ 61. Since the method is based on the Emerson reaction [ 51, phenolic compounds give different colour reactions when treated with A-aminoantipyrinc and chloramine-‘I’, e.g. phenol (red), pyrogallol and resorcinol
205
(brown) and 4-phenylphenol, salicylic acid and benzidine (pale yellow). Aromatic compounds lacking a phcnolic or amino group do not give any colour reaction, so this method can be used to estimate 2-phenylphenol in the presence of biphenyl. In the presence of other phenolic compounds, the separation of 2-phenylphenol by t.1.c. is required. REFERENCES 1 2 3 4 5 6
A. P. R. 60 E. E. A.
Rajzman, Analyst (London), 95 (1970) 490. H. Caulfield and R. J. Robinson, Anal. Chem., 25 (1955) Mistres. M. Dudieuzers-Priu, J. C. Gaillard and J. Tourtc, (1967) 331. Kroller, Dt. LchensmittRdsch., 63 (1967) 242. I. Emerson, J. Org. Chem., 8 (1943) 417. Rajzman, Analyst (London), 97 (1972) 271.
982. Ann.
Fals. Expert.
Chim..
Short
Chimica Acta, 84 (1976) 203-205 Scientific Publishing Company, Amsterdam
Communication - ________._. ___..-.-.---...
A SENSITIVE
K. L. BAJAJ**, Department (India) (Received
COLORIMETRIC
_._ ..-. ----
-
Printed
in The Netherlands
._. _ __
DETERMINATION
--_..
OF 2-PIIENYLPIIENOL*
I. R. MILLER and I. S. BHATIA
of Chemistry 23rd June
and Biochemistry.
Punjab
Agricultural
Uniwrsity,
Ludhiana
1975)
2-Phenylphenol is used [l] zs a fungicide citrus fruits and as a preservative for paints,
for the post-harvest
treatment
of
cosmetics and sizing materials [ 21. This communication describes a sensitive colorimctric method for the micro determination of Z-phenylphenol with 4-aminoantipyrine (4-aminophenazone) and chloramine-T which is more sensitive and accurate than the methods in which potassium hexacyanoferrate(II1) is used as the oxidizing agent [ 3-4 1.
Experimental Reagents and equipment. Solutions wcrc prepared from analytical-grade reagents. Organic solvents were distilled before use. Aqueous solutions were prepared from twice-distilled deionized water. For the stock 2-phenylphcnol solution (0.001 M), of 17 mg of 2-phcnylphenol was dissolved in 100 ml of dioxane. A Spectronic 20 Bausch and Lomb calorimeter with lo-mm cell was used.
Calibration curue. Take appropriate amounts of the stock solution of 2-phenylphenol (0.01, 0.02, 0.04, 0.06, 0.08, 0,l and 0.12 ml) in 25mlmeasuring flasks. Add 4 ml of aqueous 1 % (w/v) chloramine-T solution followed by 0.5 ml of aqueous 0.4 % (w/v) 4-aminoantipyrine solution and dilute to the mark with sodium carbonate-hydrogencarbonate buffer (pH 9.7). Prepare the blank similarly, without 2-phenylphcnol, and read the absorbance at 520 nm against the blank. The color is stable for at least 3 h. Results and discussion The reaction product of 4-aminoantipyrine with 2-phenylphenol in the presence of chloramine-‘I’ as oxidizing agent has a sharp absorption maximum at 520 nm. Beer’s law holds in the range 0.17-2.4 - 10m5 g of 2-phenylphenol -----. *Paper presented in the 43rd Annual Meeting of the Society of Biological (India). Ludhiana. November. 1974. **Present address: Tocklai Experimental Station, Jorhat-8, Assam, India.
Chemists.
204
per 25 ml of the final solution. When aliquots (0.06 ml) of the stock solution of 2-phenylphenol were treated with 2, 4, 6 and 8 ml of chloramine-T solution, the presence of excess of chloramine-T did not interfere with the absorbance, and 4 ml was used in subsequent determinations. Similarly, an excess of 4-aminoantipyrine did not affect the absorbance, and 0.5 ml of its solution was used subsequently. Since the reaction of 4-aminoantipyrine with phenolic compounds takes place at alkaline pH [5], aliquots (0.06 ml) of 2-phenylphenol solution were treated with carbonate-hydrogencarbonate buffers of pH 9.2,9.7, 10.2 and 10.7. No change in absorbance in this pH range was observed, and pH 9.7 was used subsequently, as recommended by previous workers [ 3-4 1. The results of replicate analyses (Table 1) show that the method is accurate and reproducible. TABLE
1
Reproducibility -_.-. --
of the determination of 2-phenylphenol --..-. --..-.-
Weight taken (pg) Mean value found (5 determinations) S.d. R.s.d. -_..-_-_-.
-.--
20.4 19.52
5.1 4.98
(JIM)
-...-._
0.0374 0.75 lo -..-.
---_
0.031 G 0.16 70 --
Percentage recovery from thin-layer chromatograms. T.1.c. is often used for the separation of 2-phenylphenol. The stock solution of 2-phenylphenol (10 ~1) was applied to an activated silica gel G plate, which was developed in chloroform-acetone (1: 1) and viewed under U.V. light to locate the 2-phenylphenol, which was eluted with dioxane. The solution was concentrated and the volume made up to 5 ml. For lo-~1 aliquots, the recovery was 99.7 f 1.5 (4 determinations). Determination of 2-phenylphenol in urine. A known volume of a concentrated ethyl acetate extract of rat urine was subjected to t.1.c. as described above. The concentration of 2-phenylphenol found by this method in 0.1 ml of the cluate was 18.8 pg; when hexacyanoferratc(II1) was used as an oxidizing 510 nm) a value of i6.6 pg was obtained. agent (A,,, Sensitivity and interferences. The minimum quantity of 2-phenylphcnol detected by this method was 6.8 - 10s8 g ml-‘, hence the method is more sensitive than those employing [ 3, 41 potassium hesacyanoferrate( III) as osidant.This method is also more convenient than that recently proposed by Rajzman [ 61. Since the method is based on the Emerson reaction [ 51, phenolic compounds give different colour reactions when treated with A-aminoantipyrinc and chloramine-‘I’, e.g. phenol (red), pyrogallol and resorcinol
205
(brown) and 4-phenylphenol, salicylic acid and benzidine (pale yellow). Aromatic compounds lacking a phcnolic or amino group do not give any colour reaction, so this method can be used to estimate 2-phenylphenol in the presence of biphenyl. In the presence of other phenolic compounds, the separation of 2-phenylphenol by t.1.c. is required. REFERENCES 1 2 3 4 5 6
A. P. R. 60 E. E. A.
Rajzman, Analyst (London), 95 (1970) 490. H. Caulfield and R. J. Robinson, Anal. Chem., 25 (1955) Mistres. M. Dudieuzers-Priu, J. C. Gaillard and J. Tourtc, (1967) 331. Kroller, Dt. LchensmittRdsch., 63 (1967) 242. I. Emerson, J. Org. Chem., 8 (1943) 417. Rajzman, Analyst (London), 97 (1972) 271.
982. Ann.
Fals. Expert.
Chim..
