Acetylsalicylic Acid

CAS Number 50-78-2
Molecular Formula C9H8O4
Molecular Weight 180.159 g/mol
LogP 1.2
  • aspirin
  • 2-Acetoxybenzoic acid
  • 50-78-2
  • 2-(Acetyloxy)benzoic acid
  • Acetylsalicylate
  • O-Acetylsalicylic acid
  • o-Acetoxybenzoic acid
  • Acetosal
  • Acylpyrin
  • Polopiryna
  • Ecotrin
  • Salicylic acid acetate
  • Acenterine
  • Acetophen
  • Colfarit
  • Easprin
  • o-Carboxyphenyl acetate
  • Enterosarein
  • Aceticyl
  • Acetonyl
  • Acetosalin
  • Acetylin
  • Aspergum
  • Aspirdrops
  • Benaspir
  • Micristin
  • Pharmacin
  • Premaspin
  • Salcetogen
  • Temperal
  • Ecolen
  • Empirin
  • Endydol
  • Rhodine
  • Saletin
  • Rheumintabletten
  • Solprin acid
  • Acidum acetylsalicylicum
  • Acetisal


HPLC Separation of Components of Excedrin

Excedrin is over-the-counter pain reliever containing acetaminophen, caffeine and aspirin as active ingredients of this drug composition. Acetaminophen (paracetamol) is used as analgesic and pain reliever. It is a neutral compound with low hydrophobicity. Aspirin or acetylsalicylic acid is used as analgesic and anti-inflammatory component of many OTC compositions. It is weakly acidic and slightly hydrophobic compound. Caffeine is xanthine alkaloid which is psychoactive stimulant drug. All four compounds are separated on mixed-mode Primesep 100 HPLC column with acetonitrile/water/TFA mobile phase. In this HPLC application compounds are retained by reversed phase mechanism. This HPLC method is short and robust.

Application Analytes:

Acetylsalicylic Acid
Benzoic Acid

USP Methods for the Analysis of Aspirin (Acetylsalicylic acid (ASA)) Using Legacy L1 Column
  Application Notes: Aspirin is one of the oldest analgesics. While it is one of the oldests analgesics, it is still widely used today, and is still one of the most common drugs. According to the USP methods, aspirin contains not less than 99.5% and no more than 100.5 percent of aspirin calculate on a dried basis. The USP HPLC method for the separation of aspirin was developed on Legacy L1 column according to the US Pharmacopeia methodology. L1 classification is assigned to reversed-phase HPLC column containing C18 ligand. Support for the material is spherical silica gel with particles size 3-10 um and pore size of 100-120A. Resolution between critical pairs corresponds to rules and specifications of USP. Application Columns: Legacy L1 C18 HPLC column Application compounds: Aspirin and salicylic acid Mobile phase: 20 mM AmFm pH 3.0/MeCN- 75/25 Detection technique: UV Reference: USP35: NF30


Column Legacy L1, 4.6x300 mm, 5 µm, 100A
Mobile Phase MeCN - 25%
Buffer AmFm pH 3.0 20 mM -  75%
Flow Rate 1.0 ml/min
Detection UV, 250 nm


Class of Compounds Drug, Acid, Hydrophobic, Ionizable
Analyzing Compounds Aspirin (Acetylsalicylic acid (ASA))

Application Analytes:

Acetylsalicylic Acid