Isocratic and Gradient Elution Pumping Modes HPLC part 3

Isocratic vs. Gradient Elution Modes & Isocratic and Gradient Elution Pumping Modes 

Isocratic Elution

  • A single composition of solvents is used for the duration of the separation
  • Later eluting peaks are broader than earlier eluting peaks because of dispersion
  • Steps must be taken to periodically flush the column at higher solvent strength to clean it of intractable materials that build up from sample injections

Gradient Elution

  • The composition of solvents is changed either continuously or stepwise
  • In general, peaks are sharper throughout the chromatogram when compared to isocratic elution
  • Some separations may be achieved which are not possible using isocratic elution
  • Chromatogram run times may be shorter when compared to isocratic elution. 

Isocratic and Gradient Elution Pumping Modes

Isocratic Pump

A single channel pump which requires the user to pre-mix the mobile phase. Composition remains constant with time.

Quaternary Low Pressure Gradient Pump

A 4 channel pump which creates mixtures of separate solvent channels under software control. Mixing is done before the pump heads. Composition may be changed with time.

Binary High Pressure Gradient Pump

A 2 channel pump which creates mixtures of 2 solvents under software control. Mixing is done after the pump heads. Composition may be changed with time.

Comments

Post a Comment

Popular posts from this blog

HPLC basic Training : code VJ HPLC-01

Image
Introduction to HPLC Basic HPLC System Components Isocratic vs. Gradient Elution Modes Screening Gradient – Powerful for Method Development Available Detectors for HPLC HPLC Columns The Chemistry of Bonded Phases The Phenomenon of Hydrophobic Retention Introduction to HPLC High Performance Liquid Chromatography (HPLC) is a process of separating components in a liquid mixture. A liquid sample is injected into a stream of solvent ( mobile phase ) flowing through a column packed with a separation medium ( stationary phase ). Sample components separate from one another by a process of  differential migration  as they flow through the column. As bands emerge from the column, flow carries them to one or more detectors which deliver a voltage response as a function of time. This is called a  chromatogram . For each peak, the time at which it emerges identifies the sample constituent with respect to a standard. The peak’s area represents the quantity. Basic HPLC System Components...
Read more

We are providing freelancing service for below mentioned activities pharmaceutical

Image
We are providing freelancing service for below mentioned activities :                                                                                     Formulation/API facilities renovation as per revised Schedule M/WHO/EU GMP.     New Pharmaceuticals project set up with a minimum budget for export /domestic supply of medicines.                                                                                     Qualification requalifications of Instruments /Equipment.      Any kind of cleaning/process/personnel validation with protoc...
Read more

BDR Pharma Hiring For Production/ R&D Department

Image
BDR Pharma Hiring For Production/ R&D Department  1) Executive Production API Exposure Of  Reactors, Nutch Filters, NFD, Dryers, Isolators With Having Experience Of 5 To 7 Years 2) Officer/ Sr. Officer-Production API Exposure Of Reactors, Nutch Filters, NFD, Dryers, Isolators With Having Experience Of 2 To 4 Years 3) Production Manager- API • Exposure Of Handling Team, Documentation, Manufacturing Operations, Having 13 To 20 Years Of Experience In API. Exposure Of R&D Api Having 2 To 8 Years Of Experience In Relevant Field. Interested Candidate May Share Their Cv At Roshni.makkad@bdrpharma.com
Read more