Hydroxyquinoline is often used as a precipitant and extractant for the precipitation and separation of metal ions. It is also used in the manufacture of dyes, pesticides and pharmaceutical intermediates. It is often used as a stabilizer for hydrogen peroxide in cosmetics. Because of its certain toxicity, currently the EU EEC and my country’s “Cosmetic Hygiene Regulations” stipulate that hydroxyquinoline is used in leaching products. The restricted mass fraction is 0.3% in hair care products and 0.03% in non-rinsing hair care products. Therefore, the establishment of a rapid and sensitive method for the determination of hydroxyquinoline in cosmetics has important practical significance for regulating the cosmetics market and protecting people’s health. Due to differences in cosmetic bases, it will be difficult to separate hydroxyquinoline from the base, affecting its qualitative and quantitative properties. Yuexu Technology has specially launched this application scheme.
Guideline
Cosmetics Safety Technical Specifications 2015 Edition.
Scope of application
Determination of hydroxyquinoline content in rinse-off hair cosmetic products.
Chromatographic conditions
Chromatographic column: Welch Ultisil® LP-C18 (4.6×250mm, 5μm).
Mobile phase: mobile phase A (10mm sodium decane sulfonate, pH=2.25): mobile phase B (methanol)=4:6;
Column temperature: 25℃;
UV detector: 240nm;
Flow rate: 1.0mL/min;
Injection volume: 20 μL.
Chromatogram
Hydroxyquinoline Standard
| RT | Area | Area% | Height | Separation | Tailing | Plate no |
| 7.73 | 1120.90 | 86.98 | 135.49 | 1.06 | 19890.10 | |
| 8.71 | 167.75 | 13.02 | 13.03 | 3.645 | 1.29 | 12178.84 |
| Total | 1288.65 |
Shampoo samples
Standard concentration of shampoo sample
| RT | Area | Area% | Height | Separation | Tailing | Plate no |
| 7.79 | 1096.72 | 76.65 | 155.31 | 1.24 | 27447.85 | |
| 8.80 | 167.75 | 23.35 | 26.36 | 3.93 | 1.15 | 12101.81 |
| Total | 1430.77 |
Recovery
| Sample name | Standard concentration (μg/mL) | Recovery rate(%) |
| Shampoo | 135.49 | 98.3% |
Conclusion
Under these chromatographic conditions, Welch Materials acid-resistant Ultisil® LP-C18 (pH tolerance range of 0.5-8) can have a good peak shape, and because this column uses an uncapped, side chain sterically hindered protection The bonding technology avoids the instability of the column due to the hydrolysis of the end-capped small groups under acidic conditions; at the same time, it also shields the hydroxyl group to a certain extent, so that the column with polar functional groups such as hydroxyquinoline has a symmetrical peak shape , Good peak capacity can effectively separate various impurities, and meet the daily detection requirements of hydroxyquinoline in cosmetics.
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