Ionic analytes often elute too early on a reversed-phase column. Adding an ion-pairing reagent to the mobile phase gives them a hydrophobic partner and makes retention predictable. This sub-category lists HPLC-grade alkyl sulphonates in a range of chain lengths, including 1-Heptane sulphonic acid sodium salt, 1-Octane sulphonic acid sodium salt and 1-Decanesulphonic acid sodium salt, in both anhydrous and monohydrate forms, along with tetraalkylammonium salts and buffer additives.

Chain length controls retention, so a C7 reagent gives less retention than a C10 reagent at the same concentration. Pharmacopoeial methods usually specify the exact salt and hydrate. Using the monohydrate in place of the anhydrous form changes the weighed amount, so check the method closely.

Our HPLC grades are tested for UV absorbance and insoluble matter to keep baselines quiet in low-wavelength detection. Packs range from 5 g to 100 g, which suits mobile phase preparation in most QC labs. Every lot ships with a COA showing assay and UV transmission.

Ion Pairing & Chromatography Reagents: questions buyers ask

Can I swap the anhydrous salt for the monohydrate in a method?

Yes, if you correct the weight for the difference in molecular mass so the molar concentration stays the same. The monohydrate is heavier per mole because of the water. Some regulated methods name a specific form, in which case follow the method exactly or document the change under your change control procedure.

Why is a dedicated column recommended for ion-pair methods?

Ion-pairing reagents adsorb strongly onto the stationary phase and are hard to wash out completely. A column used with them may behave differently in later methods without ion pairs. Many labs keep separate columns for ion-pair work and label them, which avoids carry-over and keeps retention stable.

Are ion-pairing reagents compatible with LC-MS?

Non-volatile alkyl sulphonates and many quaternary ammonium salts suppress ionisation and contaminate the mass spectrometer source. For LC-MS, volatile additives such as formic acid, ammonium formate or perfluorinated carboxylic acids are usually preferred. Use the sulphonates listed here mainly with UV or fluorescence detection.

Nearby categories

Analytical Reagents 1,396Volumetric Solutions & Titrants 117AAS & ICP Standard Solutions 137Indicators, Chelating Agents & Test Papers 190Stains, Fluorescent Dyes & Histology Reagents 417Synthetic, Protecting & Derivatization Reagents 342Grignard & Organometallic Reagents 385Phase Transfer Catalysts & Quaternary Ammonium Salts 72 Ionic Liquids 237Adsorbents, Ion Exchangers & Molecular Sieves 117

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