Analytical Standards

Standards for ISO 18857-2

Analysis of alkylphenols and alkylphenol ethoxylates using new 13C-labeled and deuterated internal standards according to ISO 18857-2

Please refer to Analytix 04/2007 for more information on this topic 

Alkylphenols are starting materials for the synthesis of alkylphenol ethoxylates, which are commonly used as non ionic tensides, dispersive agents in paper and leather manufacturing, emulsifiers for pesticide formulations and as auxiliary agents for drilling and flotation. The most important members are ethoxylates of nonylphenol (NP) and octylphenol (OP). The number of ethoxylate units can be as high as 100. Alkylphenol ethoxylates are produced in huge quantities; the annual worldwide usage is estimated to be around 600,000 tons [1].

As a consequence of the wide-spread use for more than forty years, alkylphenols and alkylphenol ethoxylates have become ubiquitous environmental contaminants [2,3] and have even been found in foodstuffs [4]. The environmental consequences of this bioaccumulation are of serious concern: Alkylphenols exhibit estrogen-like activity and disrupt male fertility in fish and aquatic mammals [5]. The same mechanism operates for short-chain ethoxylates of OP and NP with one to two ethoxy units.

The environmental impact of OP and NP and their mono- and diethoxylates have prompted their inclusion in national and international legislation with corresponding monitoring programs.

For an efficient monitoring of these compounds in the environment and verification of the compliance with regulations, a reliable and rugged analytical method is crucial. However, the analysis of alkylphenols and their ethoxylates is challenging, primarily because of the lack of availability of labeled internal standards.

Actually, in Germany the ISO 18857-2 for the analysis of OP, NP and their mono- and diethoxylates, including bisphenol A, in surface water is going to be worked out. The method utilizes solid phase extraction (SPE) and quantification by GC-MS after derivatization with MSTFA.

Comprehensive studies, which included interlaboratory proficiency testings, proved the suitability of the internal standards listed in Figure 2 and resulted in precise and accurate measurements of the target analytes. As a result, all internal standards so listed were included in ISO 18857-2.

For a final evaluation there will be an international interlaboratory proficiency testing in October/November 2007 in which all interested laboratories are encouraged to participate. For Information on participation, please contact the authors.

Sigma-Aldrich is pleased to offer the complete range of labeled compounds listed in ISO 18857-2 for the analysis of OP, NP and their mono- and diethoxylates. The corresponding product numbers and concentrations are listed.

Labeled octyl- and nonylphenol and associated ethoxylates, solutions in acetone

Other products for alkylphenol and alkylphenol ethoxylate analysis

Cat. No. Brand Description Package Size
442876 Supelco Bisphenol A-d16 50 mg
394866 Aldrich N-Methyl-N-(trimethylsilyl)trifluoroacetamide,
derivatization grade (MSTFA)
10 x 1 mL, 5 mL, 25 mL
442840 Supelco 4,4′-Isopropyldidenediphenol (Bisphenol A) 500 mg
442850 Supelco 4-Octylphenol 500 mg
442858 Supelco 4- tert -Octylphenol 500 mg
442873 Supelco 4-Nonylphenol 100 mg
46405 Sial 4-Nonylphenol 100 mg
46018 Sial Nonylphenol, technical mixture 1 G, 200 G

[1] Groshart, C. P.; Okkerman, P. C.; Wassenberg, W. B. W. Chemical Study on Alkylphenols. Rijksinstituut voor Kust en Zee, Netherlands,Report RIKZ/2001.029.
[2] Heemken, O. P.; Reincke, H.; Stachel, B.; Theobald, N. The Occurrence of Xenoestrogens in the Elbe River and the North Sea. Chemosphere 2001, 45, 245-259.
[3] Xie, Z.; Lakaschus, S.; Ebinghaus, R.; Caba, A.; Ruck, W. Atmospheric concentrations and air–sea exchanges of nonylphenol, tertiary octylphenol and nonylphenol monoethoxylate in the North Sea. Environ. Poll. 2006142, 170-180.
[4] Gunther, K.; Heinke, V.; Thiele, B.; Kleist, E.; Prast, H.; Raecker, T. Endocrine Disrupting Nonylphenols Are Ubiquitous in Food.  Environ. Sci. Technol. 2002, 36, 1676-1680.
[5] Nimrod, A. C.; Benson, W. H. Environmental estrogenic effects of alkylphenol ethoxylates. Crit. Rev. Toxicol.1996,26, 335-364.

Figure 1 : GC-MS of technical grade nonylphenol and detailed mass spectrum of isomer 363-NP.

GC Conditions:

  • instrument: HP 5890
  • detector: MSD HP 5971
  • column: 5% phenyl polymethylsiloxane , 25 m x 0.25 mm, 0.25 µm, (L x ID, FT)
  • oven: 60 °C (1 min.), 10 °C/min. to 320 °C (10 min.)
  • oven programme: injector temperature: 280 °C
  • carrier gas: helium, 1 mL/min
  • injection: 2.0 µL, splitless

Figure 2: Molecular structures of 13C-labeled octyl- and nonylphenol and associated ethoxylates.

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