2-methylpentyl 2-hydroxybenzoate

Additional physico-chemical information

Description of key information

UV/vis spectra = molar absorbance coefficients were > 1000 L mol-1 cm-1 in the range of 290 nm to 760 nm, within acidic, neutral and basic conditions at 25 °C, OECD TG 101, 2021

The substance possesses the ability to absorb UV/visible radiation ‘significantly’, in the range of 290 nm to 760 nm.

UV-Vis molar absorbance data maxima and molar absorbance coefficients were, respectively :

Neutral test solution I : 306 nm and : 4.31 x 10^3 L mol-1 cm-1

Neutral test solution II : 238 nm and: 9.44 x 10^3 L mol-1 cm-1

Acidic test solution I : 306 nm and: 4.47 x 10^3 L mol-1 cm-1

Acidic test solution II : 238 nm and: 9.76 x 10^3 L mol-1 cm-1

Alkaline test solution I : 336 nm and: 5.46 x 10^3 L mol-1 cm-1

Alkaline test solution II : 246 nm and: 7.30 x 10^3 L mol-1 cm-1

Since the molar absorbance coefficients in the range of 290 nm to 760 nm were > 1000 L mol-1 cm-1, further assessment was considered appropriate.

Refer to: OECD TG 432 (2021) : in vitro 3T3 NRU phototoxicity test for further information.

Additional information

Key study, OECD TG 101, 2020 : The ultraviolet-visible (UV-VIS) absorption spectrum of the substance under neutral, acidic and alkaline conditions was determined using OECD TG 101. The initial test item stock solution in methanol, was prepared at a concentration of 1162.4 mg/L. From this further test solutions were then prepared from the stock solution, at nominal test item concentrations as follows: (i) Neutral test solution I : methanol : 2.61 x 10^-4 mg/L ; (ii) Neutral test solution II methanol : 1.05 x 10^-4 mg/L ; (iii) Acidic test solution I : 0.1 M HCl in 90/10 (v/v) ; methanol/water : 2.61 x 10^-4 mg/L ; (iv) Acidic test solution II : 0.1 M HCl in 90/10 (v/v) methanol/water : 1.05 x 10^-4 mg/L ; (v) Alkaline test solution I : 0.1 M NaOH in 90/10 (v/v) methanol/water : 2.61 x 10^-4 mg/L and/or ; (vi) Alkaline test solution II : 0.1 M NaOH in 90/10 (v/v) methanol/water : 1.05 x 10^-4 mg/L. Corresponding blank solutions were also prepared without test item. These were treated similarly to the test solutions listed above. With each matrix the UV-Vis spectrum of the blank solution was obtained first. The cuvette was rinsed, filled with the solution, and placed in the cell holder. A background-correction scan was obtained. After this, the solution was scanned again, and the spectrum of the blank solution was obtained by subtraction of the latter with the background-correction scan. Thereafter, the cuvette was rinsed, filled with a test solution and placed in the cell holder. The UV-Vis spectrum of the test solution was obtained by scanning the solution and subtraction of the scan with the spectrum of the blank solution. Data were recorded from 900 to 200 nm. Data were interpreted and reported from 900 nm to the lowest wavelength at which the medium is transparent. For methanol used in this test, 210 nm, 210 nm and 225 nm were applied as the lowest wavelengths for the neutral, acidic and alkaline solutions, respectively. In the spectra obtained with the test solutions, two absorbance maxima were observed. The molar absorption coefficient (epsilon) alternatively indicated as MEC (molar extinction coefficient) was calculated from the Beer-Lambert Law. The listed results show the wavelengths of maximum absorbance and the molar absorption coefficients. The band widths at half maximum absorbance were not calculated since the absorbance peaks were not completely resolved. The substance possesses the ability to absorb UV/visible radiation ‘significantly’, in the range of 290 nm to 760 nm. Specifically, UV-Vis molar absorbance data maxima and molar absorbance coefficients were, respectively : (i) Neutral test solution I : 306 nm and : 4.31 x 10^3 L mol-1 cm-1 ; (ii) Neutral test solution II : 238 nm and: 9.44 x 10^3 L mol-1 cm-1 ; (iii) Acidic test solution I : 306 nm and: 4.47 x 10^3 L mol-1 cm-1 ; (iv) Acidic test solution II : 238 nm and: 9.76 x 10^3 L mol-1 cm-1 ; (v) Alkaline test solution I : 336 nm and: 5.46 x 10^3 L mol-1 cm-1 and/or ; (vi) Alkaline test solution II : 246 nm and: 7.30 x 10^3 L mol-1 cm-1

Since the molar absorbance coefficients in the range 290 nm to 760 nm were > 1000 L mol-1 cm-1, further assessment was considered appropriate.
Refer to: OECD TG 432 (2021) : in vitro 3T3 NRU phototoxicity test for further information.

References:
1. Criteria for the research institute for fragrance materials, inc. (RIFM) safety evaluation process for fragrance ingredients, Food Chem Toxicol., (2015) ; 82 Suppl : S1-S19. doi: 10.1016/j.fct.2014.11.014.
2. OECD TG 432 : In Vitro 3T3 NRU Phototoxicity Test