Analysis of the Non-Ionic Surfactant Triton-X Using UltraPerformance Convergence Chromatography (UPC 2 ) with MS and UV Detection Jane Cooper, 1 Baiba Cabovska 2 1 Waters Corporation, Wilmslow, UK 2 Waters Corporation, Milford, MA, USA APPLICATION BENEFITS UPC 2 with either UV or MS detection for the analysis of non-ionic surfactant, offers: High-efficiency separation with excellent resolution for approximately 2 oligomers. Analysis time less than 2 min with PDA detection. INTRODUCTION The non-ionic surfactant Triton X- (Figure 1), an excellent detergent and wetting agent, is readily biodegradable and achieves effective performance across a broad temperature range. It can also be used as a dispersant and emulsifier for oil in water systems. Because of these properties, Triton X- is used in many household and industrial cleaning products, paints and coatings, pulp and paper, oil fields, textiles, agrochemicals, cosmetics, and industrial materials. Reduction in consumption of organic solvents. Analysis at lower temperatures than in GC or SFC. The detection of: additional minor series components; by-products; impurities; degradation products or contaminants. WATERS SOLUTIONS ACQUITY UPC 2 System Xevo TQD MassLynx Software ACQUITY UPC 2 PDA Detector Empower 3 Software KEY WORDS Triton-X, cosmetics, personal care products, household and industrial cleaning products (C 14 H 22 O(C 2 H 4 O) n ) n= 9-1 Figure 1. Triton-X- structure and chemical formula. It is essential to be able to monitor the composition of the non-ionic, octylphenol ethoxylate surfactant Triton X-, because differences in the ethoxy chain length can affect characteristics of the mixture such as viscosity, solubility, and polarity. The ability to detect the presence of by-products, impurities, degradation products or contaminants present in surfactants is equally important. In addition to identifying potential carcinogenic or allergenic compounds, the presence of impurities can also affect the efficiency of the surfactant. Surfactants are typically analyzed using techniques such as High Performance Liquid Chromatography (HPLC), 1,2 Supercritical Fluid Chromatography (SFC), 3 or Gas Chromatography (GC). 4,5 Analysis by GC and HPLC can be time consuming, as these techniques may require additional derivatization stages in order to improve sensitivity, separation or resolve volatilization issues. GC or traditional SFC techniques that employ high column temperatures can also limit the analysis of thermally labile compounds. In some cases, baseline separations for oligomers using HPLC, SFC or GC analyses are not achieved. 1
Waters UltraPerformance Convergence Chromatography (UPC 2 ) System, builds on the potential of normal-phase separation techniques such as SFC, while using proven Waters easy-to-use UPLC Technology. This application note describes the analysis Triton X- utilizing UPC 2 with PDA and MS detection. Excellent resolution for approximately 2 oligomers has been achieved using lower temperatures than GC or traditional SFC analysis, making UPC 2 more amenable for the analysis of thermally labile compounds. A significant reduction in the consumption of toxic solvents was also achieved compared to normal phase HPLC analysis. E X P E R IM E N TA L UV conditions UV system: Range: Resolution: ACQUITY UPC 2 PDA Detector 21 to 4 nm 4.8 nm UPC 2 System: ACQUITY UPC 2 Column: Column temp.: 4 C Convergence column manager back pressure: 15 psi Injection volume: 1. µl Mobile phase B: Methanol ACQUITY UPC 2 BEH 2.1 mm x 5 mm, 1.7 µm Mobile phase gradient for UV detection is detailed in Table 1. (min) Flow rate (ml/min) A B Curve 1 Initial 2. 98. 2. 2 1.25 2. 65. 35. 6 3 1.3 2. 98. 2. 6 4 2. 2. 98. 2. 6 Table 1. ACQUITY UPC 2 mobile phase gradient for UV detection. Instrument control, data acquisition, and result processing Empower 3 Software was used to control the ACQUITY UPC 2 System and ACQUITY UPC 2 PDA Detector, and provide data acquisition and processing. MS conditions MS system: Xevo TQD Ionization mode: ESI + Capillary voltage: 3.5 kv Source temp.: 15 C Desolvation temp.: 5 C Desolvation gas flow: 8 L/hr Cone gas flow: 5 L/hr Acquisition: Full scan UPC 2 System: ACQUITY UPC 2 Column: ACQUITY UPC 2 BEH 2.1 mm x 5 mm, 1.7 µm Column temp.: 65 C CCM back pressure: 16 psi Injection volume: 1. µl Mobile phase B: Methanol Mobile phase gradient for MS detection is detailed in Table 2. (min) Flow rate (ml/min) A B Curve 1 Initial 2. 97. 3. 2 2. 2. 8. 2. 6 3 21. 2. 97. 3. 6 4 23. 2. 97. 3. 6 Table 2. ACQUITY UPC 2 mobile phase gradient for MS detection. MassLynx Software was used to control the ACQUITY UPC 2 System and Xevo TQD, and provide data acquisition and processing. 2
RESULTS AND DISCUSSION UV detection results UPC 2 conditions were optimized for the separation and detection of 2 Triton X- oligomers. The UV chromatogram for a 1 mg/ml standard in isopropanol alcohol is shown in Figure 2. MS detection results The UV method demonstrated the speed and simplicity of UPC 2 for the analysis of Triton X-. With further optimization of the separation, in this example using a slower gradient, with MS detection additional characterization of the surfactant was achieved. The chromatogram for Triton X- with MS detection, using the described UPC 2 and MS conditions, is shown in Figure 3. The oligomers detected can be further identified considering the MS spectra, shown in Figure 4 for the oligomers identified as a, b, c, and d in Figure 3. Figure 2. UV chromatogram for a 1 mg/ml Triton X- standard. 3
b a 5.72 5.71 5.74 4.98 c d 7.19 4.22 7.21 3.51 7.22 7.91 2.82 2.81 8.62 9.31 2.8 9.96 2.18 1.56 11.16 1.67.1 1.25 11.71 12.26 14.36 15.95 16.36 18 2. 4. 6. 8. 1. 12. 14. 16. Figure 3. MS chromatogram for a Triton X- standard. 365 79 79 d 692 715 214 373 339 295 454 486 634 731 931 58 776 82898 117 183 1436 1456 2 3 4 5 6 7 8 9 1 12 13 14 343 665 71 714 692 715 65 543 552559 57 58 59 61 618 62 634 634 646 693 73 716 731 657 674675682 739 54 56 58 6 62 64 66 68 7 72 74 665 71 714 c 666 666 67 b 648 671 214 351 295 338 454 1347 1421 1492 574 438 589 687 732 784 87792 117136 1381 2 3 4 5 6 7 8 9 1 12 13 14 64 329 627 214 295 364 454 545 855 6587374382 95997 116 1455 2 3 4 5 6 7 8 9 1 12 13 14 299 321 577 621 626 648 671 686 649 543 634 646 556557 574 59163 612 63 589 621 655 672 687 727971 717 732733739 54 56 58 6 62 64 66 68 7 72 74 64 627 65 642 545 582 61 628 643 54655356 571 586 61 658665666673 688689 743 7374 724 724 733739 54 56 58 6 62 64 66 68 7 72 74 577 621 626 a 578 578 582 56 659 37 583 214 295 454 486 7 339 126 1426 774 861 884 978 954 197 599 696 1171 132 1461 1481 2 3 4 5 6 7 8 9 1 12 13 14 56 561 583 598 543 552 566 584 599 613621622 63 6645 65966 734 668679681 696697 716722 731 7437 54 56 58 6 62 64 66 68 7 72 74 Figure 4. Mass spectra for the individual Triton-X oligomers as indicated in Figure 3. 4
By using a slower gradient additional details can be observed, such as the detection of: additional minor series components, by-products, impurities, degradation products, or contaminants. An additional minor series present in the analyzed sample of Triton X- is shown in Figure 5. 3 e 3. 3.5 4. 4.5 5. 5.5 6. 6.5 7. 7.5 8. 8.5 9. 2.18 2.82 2.81 2.8 2.83 f 4.23 4.22 3.51 3.5 4.98 4.99 g 5.72 5.74 5.71 5.75 5.78 6.48 6.49 6.5 7.17 h 7.19 7.21 7.22 7.91 8.62 8.65 9.31 9.34 9.96 1.56 621.58 485.99 63.68 626.61 491.15 542.39 569.35 48 5 52 54 56 58 6 62 64 66 577.58 485.82 559.55 489.89 547.2 582.61 613.61 639.5 48 5 52 54 56 58 6 62 64 66 537.53 485.95 515.51 538.49 489.85 561.7 646.85 64.63 66.81 48 5 52 54 56 58 6 62 64 66 488.51 493.53 532.55 576.59 62.58 h g f e 1.67 3.19.1 1.25 2.99.88 2.8 2.47.22 1.5 1.48 7.97 8.67 6.18 3.69 5.19 5.95 6.67 7.41 8.11 4.13 4.43 5.52 6.21 7.77 4.74 6.91 8.42 8.98 9.52 1.16 1.96 11.16 11.39 11.71 12.26 14.36 12.77 12.8 12.63 13.14 13.29 14.64 15.54 15.95 16.36 16.77 59.4 542.47 57.91 63.7 635.6 659.64 48 5 52 54 56 58 6 62 64 66 18.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 1.5 11.5 12.5 13.5 14.5 15.5 16.5 Figure 5. Additional minor series highlighted in the analyzed sample of Triton X-, with respective mass spectra. 5
CONCLUSIONS Rapid, high efficiency separation with analysis time of less than 2 min with PDA detection. Excellent resolution for approximately 2 oligomers. Analysis occurs at lower temperature than in GC or SFC. Reduction in consumption of organic solvents. MS detection can be used to further characterize the surfactant, such as the identification of specific oligomers, detection of additional series components, by-products, impurities, degradation products of contaminants. References 1. R A Escott, S J Brinkworth, T A Steedman. The determination of ethoxylate oligomers distribution of Non-Ionic and Anionic Surfactants by HPLC. J Chromatography. 282: 655 661, 1983. 2. K Nakamura, Y Morikawa, I Matsumoto. Rapid Analsyis of Ionic and Non-Ionic Surfactants Homologs by HPLC. Journal of the American Oil Chemists Society. 58: 72 77, 1981. 3. B J Hoffman, L T Taylor. A Study of Polyethoxylated Alkylphenols by Packed Column Supercritical Fluid Chromatography. Journal of Chromatography. 4: 61 68; Feb 22. 4. C Bor Fuh, M Lai, H Y Tsai, C M Chang. Impurity analysis of 1,4-dioxane in nonionic surfactants and cosmetics using headspace solid-phase microextraction coupled with gas chromatography and gas chromatography-mass spectrometry. Journal of Chromatography A. 171: 141 145; 25. 5. J A Field, D J Miller, T M Field, S B Hawthorne, W Giger. Quantitative determination of sulfonated aliphatic and aromatic surfactants in sewage sludge by ion-pair/supercritical fluid extraction and derivatization gas chromatography/mass spectrometry. Analytical Chemistry. 64(24): 3161 3167; 1992. Waters, UPLC, UPC, 2 ACQUITY UPC, 2 MassLynx, Empower, and The Science of What s Possible are registered trademarks of Waters Corporation. UltraPerformance Convergence Chromatography is a trademark of Waters Corporation. All other trademarks are the property of their respective owners. 215 Waters Corporation. Produced in the U.S.A. September 215 725496EN AG-PDF Waters Corporation 34 Maple Street Milford, MA 1757 U.S.A. T: 1 58 478 2 F: 1 58 872 199 www.waters.com