QC and product screening of hair, skin, and dentalcare products with NIRS

Quality control of hair, skin, and dentalcare products continues to increase in importance for producers. Aside from safeguarding our health, it is equally important to avoid the sale of out-of-specification products. Product recalls are very expensive and have a lasting effect on a company’s reputation. Therefore, intensive testing of these different care products is essential before they are brought to the market. This article shows how utilizing near-infrared spectroscopy (NIRS) for QC and product screening is the ideal choice for producers of personal care products. Not only is the technique fast and non-destructive, it is also easy to use and does not require any chemicals.

The next sections will introduce various kinds of personal care products followed by an explanation of the NIRS analytical technique and an application example of how NIRS can be used for QC of shampoo and related products.

Haircare products:

Skincare products:

Dentalcare products:

Near-infrared spectroscopy (NIRS)—the ideal tool for quality control of hair, skin, and dentalcare products

Near-infrared spectroscopy (NIRS) has been an established method for both fast and reliable quality control of personal care and cosmetics products for more than 30 years. However, many companies still do not consistently consider the implementation of NIRS in their QA/QC labs. The reasons could be either limited experience regarding application possibilities or a general hesitation about implementing new methods.

There are several advantages of using NIRS over other conventional analytical technologies. For one, NIRS is able to measure multiple parameters in just 30 seconds without any sample preparation! The non-invasive light-matter interaction used by NIRS, influenced by physical as well as chemical sample properties, makes it an excellent method for the determination of both property types.
 

For more detailed information about NIRS as a secondary technique, please read our previous blog posts.

What is NIR spectroscopy

NIR vs IR: What is the difference

How to implement NIR spectroscopy in your laboratory workflow

NIR spectroscopy pre-calibrations: Immediate results

ASTM E1655: NIRS as a QC compliant technique

ASTM E1655 (Standard Practices for Infrared Multivariate Quantitative Analysis) is a guide for the multivariate calibration of infrared spectrometers used for determining the physical or chemical characteristics of materials. These practices are applicable to analyses conducted in the near-infrared (NIR) spectral region (roughly 780 to 2500 nm) through the mid-infrared (MIR) spectral region (roughly 4000 to 400 cm^-1).

Which parameters and applications are generally possible for NIRS analysis?

Typically, key parameters for the quality control of hair, skin, and dentalcare products such as moisture content, surfactants, active ingredients, iodine value, and total fatty matter (TFM) are determined in the laboratory by chemical and physical methods. These methods not only have high running costs – they are also time consuming.

Near-infrared spectroscopy (NIRS) can overcome these issues as it requires neither chemicals nor sample preparation, provides results in less than a minute, and it can even be used by non-chemists. Furthermore, multiple chemical and physical parameters can be determined simultaneously. The combined benefits of this technology make NIRS the ideal solution for many daily QA/QC measurements or even ad-hoc atline analysis.

Application example: Quality control of surfactants in shampoo with NIRS

Determination of surfactants like sodium laureth sulfate (SLES), cocamidopropyl betaine (CAPB), cocamidopropylamine oxide (CAW), cocamide diethanolamine (DEA), and carbopol in shampoo is a cost- and time-intensive process due to the use of large volumes of chemicals required for these analyses with conventional lab techniques.

To show some of the benefits of using NIRS as a QC tool, shampoo samples were measured with a Metrohm DS2500 Solid Analyzer in transflection mode over the full wavelength range (400–2500 nm). A DS2500 Slurry Cup was employed, which simplifies the positioning of the sample and cleaning of the sample vessel. The 1 mm gold diffuse reflector defines the same pathlength for all measurements to guarantee reproducible results.

The obtained Vis-NIR spectra (Figure 1) were used to create prediction models for the determination of several key ingredients in shampoo. The quality of the prediction models was evaluated using correlation diagrams which display the correlation between Vis-NIR prediction and primary method values (Figure 2). The respective figures of merit (FOM) display the expected precision of a prediction during routine analysis (Figure 2 and Table 1).

This solution demonstrates that NIR spectroscopy is excellently suited for the analysis of multiple active ingredients in shampoo without sample preparation or using any chemical reagents. Additionally, results are obtained in less than one minute, saving users valuable time.

Summary

Quality control is a critical aspect for the substances we use on our skin and for our dental hygiene. Because of our daily exposure to personal care products, it is critical that they follow industry standards and regulations and are safe to use. Conventional wet chemical analysis of various QC parameters in hair, skin, and dentalcare products involves the use of chemical reagents, skilled chemical analysts, and requires time to prepare and analyze the samples. Near-infrared spectroscopy (NIRS) is a fast alternative, requiring no chemicals or sample preparation steps, and can be used by non-technical personnel. Multiple parameters can be measured at once, further reducing analysis time, and results are delivered in less than a minute.

Your knowledge take-aways

Application Note: Quality Control of Shampoo

On-demand webinar: NIR spectroscopy in personal care industry: The ideal tool for QC and product screening

Metrohm DS2500 Analyzers