NP-40

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| ImageFile = Polyethylene glycol nonylphenyl ether.svg

| ImageSize = 200px

| IUPACName =

| OtherNames = Polyethylene glycol nonylphenyl ether; Nonyl phenoxypolyethoxylethanol; Nonoxynol-40

| Section1 = {{Chembox Identifiers

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo = 26027-38-3

| ChemSpiderID = 23159

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = 4867M0AEJI

| PubChem = 24773

| EC_number = 500-024-6

| UNNumber = 3082

| ChEMBL = 194034

| DTXSID = DTXSID9058600

| StdInChI=1S/C19H32O3/c1-2-3-4-5-6-7-8-9-18-10-12-19(13-11-18)22-17-16-21-15-14-20/h10-13,20H,2-9,14-17H2,1H3

| StdInChIKey = BLXVTZPGEOGTGG-UHFFFAOYSA-N

| SMILES = CCCCCCCCCC1=CC=C(C=C1)OCCOCCO

}}

| Section2 = {{Chembox Properties

| Formula = H(C₂H₄O)_nO(C₆H₄)C₉H₁₉

| MolarMass = Variable

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| Section3 = {{Chembox Hazards

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NP-40 (also known as Tergitol-type NP-40 and nonyl phenoxypolyethoxylethanol[https://www.thermofisher.com/order/catalog/product/28324 NP-40 Surfact-Amps Detergent Solution]) is a commercially available detergent with CAS Registry Number 9016-45-9. NP-40 is an ethoxylated nonylphenol for non-ionic surfactants and can act as emulsifier and demulsifier agent.

NP-40 is often used to break open all membranes within a cell, including the nuclear membrane {{Citation needed|date=July 2022}}. To break only the cytoplasmic membrane, other detergents such as digitonin can be used.

NP-40 has applications in paper and textile processing, in paints and coatings, and in agrochemical manufacturing.

Care should be taken to avoid confusing NP-40 with Nonidet P-40 (octyl phenoxypolyethoxylethanol) which is currently out of production. Nonidet P-40 ("Non-Ionic Detergent") was originally manufactured and trademarked by the Shell Chemical Company,{{Cite journal | doi=10.1039/AR96057FP001| title=Front matter| journal=Annual Reports on the Progress of Chemistry| volume=57| pages=P001| year=1960}} but was phased out of production in the early 2000s. Confusingly, biochemical protocols published between the 1960s{{Cite web | url=https://www.cabdirect.org/cabdirect/abstract/19702702616 |title = CAB Direct}} and 2000s refer to Shell's Nonidet P-40 as NP-40. Shell's original Nonidet P-40 had a hydrophilic-lipophilic balance (HLB) value of 13.5,[https://www.dow.com/assets/attachments/business/pcm/tergitol/tergitol_np-9/tds/tergitol_np-9tds.pdf TERGITOL NP-9 Surfactant ] as opposed to 12.9 for the currently available IGEPAL CA-630,{{Cite web | url=https://www.elsevier.com/books/guide-to-protein-purification/burgess/978-0-12-374536-1 |title = Guide to Protein Purification, Volume 463 - 2nd Edition}} indicating that the currently available compound is more potent than the compound used in older publications. Indeed, according to a 2017 report,{{Cite journal |doi = 10.1139/bcb-2016-0141|pmid = 28177759|title = Use of substitute Nonidet P-40 nonionic detergents in intracellular tubulin polymerization assays for screening of microtubule targeting agents|journal = Biochemistry and Cell Biology|volume = 95|issue = 3|pages = 379–384|year = 2017|last1 = Sinha|first1 = S.|last2 = Field|first2 = J.J.|last3 = Miller|first3 = J.H.|doi-access = free}} an additional dilution factor of 10 was required for the currently available NP-40 ("Nonidet P-40 substitutes") to match the activity of the previously available, and now discontinued, Shell's Nonidet P-40.