AN-NIR-054
2020-03
Quality Control of Shampoo
Chemical-free and fast determination of surfactants in shampoo
Summary
Determination of sodium laureth sulfate (SLES), cocamidopropyl betaine (CABP), 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 per analysis.
This application note demonstrates that the DS2500 Solid Analyzer operating in the visible and near-infrared spectral region (Vis-NIR) provides a cost-efficient and fast solution for a simultaneous determination of sodium laureth sulfate (SLES), cocamidopropyl betaine (CABP), cocamidopropylamine oxide (CAW), cocamide diethanolamine (DEA), and carbopol in shampoo. With no sample preparation or chemicals needed, Vis-NIR spectroscopy allows for the analysis of these parameters in less than a minute.
Results
The obtained Vis-NIR spectra (Figure 2) were used to create prediction models for quantification of the sodium laureth sulfate (SLES), cocamidopropyl betaine (CABP), cocamidopropylamine oxide (CAW), cocamide diethanolamine (DEA), and carbopol in shampoo. The quality of the prediction models was evaluated using correlation diagrams, which display the relationship between Vis-NIR prediction and primary method values. The respective figures of merit (FOM) display the expected precision of a prediction during routine analysis.
Result sodium laureth sulfate
Figures of merit | Value |
---|---|
R2 | 0.998 |
Standard error of calibration | 0.13% |
Standard error of cross-validation | 0.14% |
Result cocoamidopropyl betaine
Figures of merit | Value |
---|---|
R2 | 0.996 |
Standard error of calibration | 0.04% |
Standard error of cross-validation | 0.05% |
Result cocoamidopropylamine oxide
Figures of merit | Value |
---|---|
R2 | 0.998 |
Standard error of calibration | 0.031% |
Standard error of cross-validation | 0.058% |
Result cocoamide diethanolamine
Figures of merit | Value |
---|---|
R2 | 0.998 |
Standard error of calibration | 0.034% |
Standard error of cross-validation | 0.036% |
Result carbopol
Figures of merit | Value |
---|---|
R2 | 0.969 |
Standard error of calibration | 0.290% |
Standard error of cross-validation | 0.410% |
Conclusion
This application note demonstrates the feasibility of NIR spectroscopy for the analysis of sodium laureth sulfate (SLES), cocamidopropyl betaine (CABP), cocamidopropylamine oxide (CAW), cocamide diethanolamine (DEA), and carbopol in shampoo. In comparison to wet chemical methods running costs are significantly lower when using NIR spectroscopy (Tabel 7 and Figure 8).
Lab method | NIR method | |
---|---|---|
Number of analyses per day | 10 | 10 |
Cost of operator per hour | $25 | $25 |
Costs of consumables and chemicals (SLS, CABP, CAW, DEA, carbopol) | $5 | $1 |
Time spent per analysis (SLS, CABP, CAW, DEA, carbopol) | 5 min | 1 min |
Total running costs (per year) | $18,188 | $2,063 |