Detergents and Cleaners Testing

Cumme, G. A., Blume, E., Bublitz, R., Hoppe, H., & Horn, A. (1997). Journal of Chromatography A, 791(1-2), 245-253.

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) effectively determines the distribution of single polymer species in non-ionic polyoxyethylene detergents, such as Triton X-100 and 114, Tween 20, and Brij 35.

MALDI-MS analysis results for these detergents are shown in the figure. These detergents consist of highly heterogeneous polymer mixtures with varying numbers of ethoxy groups. Based on the known stoichiometry of these detergents, the main peaks in the spectra correspond to Na⁺ adducts, while the adjacent peaks to the right represent K⁺ adducts. The observed masses align with calculated values within a 0.08% margin of error.

Spectra for Tween and Brij detergents are more symmetrical than those of the Triton family and display additional peaks associated with Na⁺ adducts of species containing two extra CH₂ groups. The Triton detergents exhibit fewer ethoxy groups compared to Brij 35 and Tween 20, causing the smallest species' peaks to be obscured by matrix peaks.

In addition to polyoxyethylene detergents, MALDI-MS successfully analyzed non-ionic detergents such as Mega 8 and n-octylglucoside, as well as zwitterionic detergents like Chaps, Chapso, and sulfobetaine SB 14.

Olsson, John, Patrik Ivarsson, and Fredrik Winquist. Talanta 76.1 (2008): 91-95.

A voltammetric electronic tongue (ET) and a conductivity meter were utilized to estimate detergent quantities in wastewater from washing machines. Detergent levels in over sixty samples were also analyzed using a HPLC reference method. The electronic tongue demonstrated higher prediction accuracy, though both methods proved effective.

The detergent composition, particularly the supporting electrolyte, significantly influences the accuracy of detergent quantification via conductivity measurements. Two surfactants, alkyl benzyl sulfonate (ABS) and ethoxylated fatty alcohol (EOA), were identified and analyzed using HPLC. Their behavior during the wash cycle showed notable differences: ABS rinsed away alongside the supporting electrolyte, while EOA tended to remain within the machine and laundry.

Prediction models for ABS were accurate with both ET and conductivity measurements, primarily due to its correlation with the supporting electrolyte. In contrast, EOA's lack of correlation with the supporting electrolyte posed challenges for conductivity-based predictions. However, ET prediction models showed potential for accurately estimating EOA levels.

Ventura-Gayete, Josep Francesc, et al. Microchemical journal 78.1 (2004): 47-54.

The use of multicommutation in attenuated total reflectance (ATR) measurements with Fourier Transform Infrared (FTIR) spectrometry has been assessed to minimize sample consumption and waste, while also reducing the risk of cell breakage. A new multicommutation ATR-FTIR method has been developed for determining sodium alpha-olefin sulfonate (AOS) in liquid detergent formulations.

This method offers several advantages, including minimal sample usage (96 µL per 100 determinations) and improved analytical throughput (23 determinations per hour compared to 15 in manual mode). Results for reference samples containing 7.52% to 9.52% (w/w) AOS showed a margin of error within 0.5% (w/w), with a mean precision of 0.3% relative standard deviation (RSD). Recovery studies confirmed the method's accuracy, with average recovery values around 100%.