Preservative Analysis in Wet Wipes and Cosmetics by HPLC
Analysis of preservatives by HPLC in wet wipes and cosmetic products and the effects of using monolithic columns on analysis performance and cost instead of standard C18 columns, which become unusable in a short time due to high pressure in analysis.
Purpose of the Study
Conventional C18 columns used in the analysis of wet wipes and cosmetics become clogged quickly, become unusable in a short time with high pressure, and the shortening of the column life results in increased analysis costs In order to eliminate this situation, it is aimed to extend the column life time by using monolithic silica columns instead of standard C18 columns, and to perform the analysis more effectively and efficiently as a result of saving in the amount of acetonitrile and time.
Thanks to its monolithic silica technology, it makes it possible to make ultra-fast and robust separations with standard HPLC systems. Monolithic columns can be used with systems such as UHPLC, LCMSMS as well as standard HPLC systems.
Monolithic columns consist of a single piece of polymeric silica gel filler in the form
of a rod, unlike columns with conventional particulate filler (5 μm, 3 μm, 2 μm, etc.). While 13-15 nm pore size mesopores on Polymeric Silica Gel provide low column back pressure at high flow rates, macropores with 1.15-2 μm pore size increase column selectivity.
Especially in viscous products such as cream, pomade, syrup and food samples with complex matrix, monolithic columns are frequently preferred because they have a much longer life time (approximately 3 times) than conventional particle- filled columns. This method can be applied to products such as cream, eyeliner, mascara, blush, lipstick.
Methods and Materials Our study was carried out using Shimadzu LC-2030C Plus 3D HPLC. Analyzes were performed using a Merck Chromolith® column.
Equipment and Chemicals
1. HPLC
2. Detector (Photodiode array - PDA)
3. HPLC Column
4. Analytical balance (with an accuracy of 0.001 g)
5. Ultra pure water device
6. Syringe filter (0.45 μm)
7. Mobile phase filtration device
8. Automatic pipette (0-1 mL)
9. Laboratory glassware Mixer
10. Vial Standards
11. Acetonitrile (ACN)
12. Sodium acetate (CH3COONa)
13. pH meter
1.Benzoic Acid, Phenoxyethanol (Phenoxyethanol), Dehydroacetic Acid
Preparation of Samples and Solutions
• Standard stock solution of 2 ppm Benzoic Acid, 15 ppm Phenoxyethanol, 3 ppm Dehydroacetic Acid is prepared.
• By adding the internal standard, it is diluted to the desired concentrations, filtered through a 0.45 μm filter and the resulting filtrate is put into vials.
• In the sample preparation part; When wet wipes are squeezed, the liquid that comes out is transferred to a beaker. 1mL sample and internal standard are diluted with 50% ACN/Water and filtered through a 0.45 μm filter and the resulting filtrate is placed in vials.
Analytical Conditions
Device: Shimadzu HPLC
Model: LC-2030C Plus 3D
Column: Merck Chromolith® Performance
(100mm x 4.6mm)
Detector: PDA Detector
Wavelength: 254 nm
Column Furnace Temperature: 40 °C
Injection Volume: 10 μL
Flow Rate: 2 mL/min
Duration: 4 min
Mobile Phase: 20 mM CH3COONa pH 4.2
ACN (75/15)
[caption id="attachment_153974" align="aligncenter" width="496"]
Figure 1. Benzoic acid, Phenoxyethanol (Phenoxyethanol), Dehydroacetic acid[/caption]
[caption id="attachment_153975" align="aligncenter" width="542"]
Figure 3. Sample chromatogram[/caption]
2. Sodium Benzoate, Potassium Sorbate
Preparation of Samples and Solutions
• 3.6 ppm sodium benzoate, 3.6 ppm potassium sorbate standard stock solution is prepared and diluted with 50% ACN/water to the desired concentrations, filtered through a 0.45 μm filter and the resulting filtrate is placed in vials.
• In the sample preparation part; Wet wipes are squeezed and poured into a beaker containing liquid. 1mL sample and internal standard are diluted with 50% ACN/Water and filtered through a 0.45 μm filter and the resulting filtrate is placed in vials.
Analytical Conditions
Instrument: Shimadzu HPLC
Model: LC-2030C Plus 3D
Column: Merck Chromolith® Performance
(100mm x 4.6mm)
Detector: UV detector
Wavelength: 254 nm
Column Furnace Temperature: 40 °C
Injection Volume: 10 μL
Flow Rate: 2 mL/min
Duration: 4 min
Mobile Phase: 20 mM CH3COONa pH 4.2
ACN (75/15)
As a result of the analyzes performed with Merck Chromolith® column and Shimadzu LC-2030C Plus 3D HPLC, 50% savings were achieved in acetonitrile consumption compared to the standard C18 column, and analysis times were reduced by half.
However, in the user feedback, they started the analysis with a column pressure of 110 bar using the new C18 columns, and they found that the relevant columns deform quickly by going up to high pressures in a short time; On the other hand, it has been observed
that Merck Chromolith® column is more durable and long-lasting against clogging with a pressure of 25 bar.
Reference
Ant Teknik Aplikasyon Notu-KMY016 HPLC ile Islak Mendil ve Kozmetik Ürünlerinde Koruyucu Analizi
Ömer Halit Turmuş
Chemist
Application Team Leader
Ant Teknik
