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Blog posts of '2019' 'November'

How to Prepare a Sample for HPLC Analysis | Greyhound Chromatography

How to Prepare a Sample for HPLC Analysis

 

 

High-performance liquid chromatography (HPLC) is a analytical chemistry technique used to separate, quantify and identify each component in a mixture. Components are mixed in a pressurized liquid solvent which pass the sample through a HPLC column filled with a solid  adsorbent material. Each component in the sample interacts slightly differently with the adsorbent material, causing different flow rates for the different components and leading to the separation of the components as they flow out of the column.  The sample is mixed with solvents in varying dilutions and can be pre-filtered before the sample is put into the column to ensure purity of the results, where a sample has to pass through the column at a regular or fast speed a HPLC pump is used.  

 

Sample preparation is vital to high quality reproducable and specific results, often overlooked methodical sample preparation can improve efficiency in the laboratory.  Sometimes seen as a laborious task sample preparation isn't always viewed as the most efficient use of time in the laboratory.  HPLC and increasingly UHPLC is one of the most commonly used high pecision analytical methods in today's fast paced modern laboratory.  A sample needs to be prepared so that it can be directly injected into a HPLC column.  Firstly the sample needs to be dissolved in an appropriate solvent; methanol and acetonitrile are favourite choices, for a variety of reasons; there are many guides available as to the proportion on solvent in relation to your sample; some methods are tried and tested some are just a matter of trial and error.  Chromatography forums provide a wealth of experience that is freely shared via the Internet.

Depending on the sample to be analysed, whether it be for animal biological fluids, drinks, food, human biological fluids, petrochemical residues, pharmaceutical analysis, toxicological residues, waste waters, the sample will need to be filtered prioir to injection.  Solid Phase Extraction (SPE) tubes provide an excellent clean up method or a syringe filter with a suitable membrane to ensure that your sample is free of particles that may cause intereference during detection and will prevent blockages to your column.   Syringe filters are the most efficient method of pre-filtering the sample for sample with complex properties or for small volumes, they come in a variety of membranes and differing porisities.  It is important that the sample is a clean as possible before it is introduced to the column, taking time at this stage to ensure that the sample is a clean as it can be is worth the extra time.  

Problems with peaks, particularly Ghost Peaks can be detected either with the first injection or problems may present themselves during the course of your analysis leading to a gradual deterioration in your results.  A poorly prepared sample may lead to you having to repeat the whole process, it may even involve you having to clean the column if the sample is too contaminated.  Taking extra time to clean the sample will save valuable laboratory time in the long run. 

A clean sample will help to ensure:

  • High sensitivity of the HPLC Column
  • Accurate, reproducable results
  • Fewer false-positive peaks
  • Reduced leachables
  • Low background noise
  • No blockages in the column

Using ultra pure water can also have its advantage particularly for pharmaceutical analysis where the need for the purest water is paramount.  Scientific research has proved that more than 80% of problems experienced during HPLC analysis are directly attributable to water purity.  Biosolve Ultra Pure water is supplied by Grehoyhound Chromatography in the UK and to laboratories world-wide.  With less than 0.0002%w/w residues after evaporation, the HPLC grade water from Biosolve is filtered through 0.2µm and bottled under inert gas.  

 

Some scientists prefer to use an automated sample preparation methods to eliminate human error, samples can become unreliable where dilution has been carried out manually use hand to eye determination of sample size and not a regulated reproduction of a sample using a elctronic pipette, for example.  Automated sample preparation can aid productivity by speeding up the analysis process, this is partciularly useful for UHPLC where speed of analysis under high pressure is essential.  Triple quad systems provide increased sensitivity at lower analyte concentrations, allowing high throughput of smaples.  The laboratory environment is increasingly complex, particularly in the field of biological research and analysis.  The need for research and drug development in the area of Cancer research alone is driving new developments every day at the edge of treatment devlopment. 

 

 

 

 

 

 

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3M Petrifilm | Greyhound Chromatography

3M Petrifilm Group of Products

 

It is widely considered that labour is one of the most significant factors in the cost of traditional microbial testing.  The ready to use format of Petrifilm count plates can greatly reduce the labour time involved in traditional testing, saving valuable laboratory hours and freeing technicians to undertake other testing.  In an industry study conducted with 292 food processing plants, companies saved an average of 3.7 hours per day of technician time and all improved efficiency testing by using Petrifilm count plates. 

3M Petrifilm

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SGE eVol Progammable Electronic Syringe | Greyhound Chromatography

eVol Programmable Syringe

eVol Progammable Electronic Syringe      Trajan Scientific Logo      eVol Brochure

Every One an Expert

eVol® XR digital analytical syringe is the coupling of two precision devices: a digitally controlled electronic drive and an XCHANGE® enabled analytical syringe. eVol XR syringes are easily and quickly changed allowing them to be dedicated to individual liquids or methods to prevent possible cross-contamination of reagents.

Features and Benefits

  • Suitable for use with volatile samples. Variable speed of operation.
  • Easily calibrated and calibration factors saved for each syringe, enabling laboratories to comply with stringent global laboratory standards (e.g. GLP, GMP, FDA).
  • Programmable and able to store a laboratory workflow (up to 98 steps).  Password protection options enabling standardization of work processes.
  • Reduces the need for serial dilutions. Recommended Applications
  • Preparation and addition of Standards.
  • Precise dispensing of aqueous and non-aqueous liquids.
  • TLC spotting.
  • Micro titrations.
  • GC and LC instrument injections.
  • NMR sample Preparation
  • MEPS

 

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Buy Perfluorinated Reference Standards | Wellington Laboratories | Greyhound Chromatography

Perfluorinated Compounds

Wellington Laboratories Logo     Wellington Laboratories Catalogue Cover Image

In addition to Wellington's range of certified reference standards for linear perfluoroalkyl carboxylic acids and perfluoroalkane sulfonates, Wellington also offers individual reference standards of some branched isomers.  It is well docuumented that branched and linear perfluorinated compounds can have varying isomer rofiles in biological samples.  Therefore to aid researchers in the analysis of these compounds, Wellington is adding two additiojnal branched perfluoroalkyl reference standards (P355TMHxA and NaP6MHpS to our line of perfluorinated compounds.

Also, to supplement existing inventory of polyflurinated secondary telomer alcohols, we are introducing a 1-perfluoropentyl ethanol (5:2sFTOH) reference standard.

Buy Now Online: NaP6MHpS

Buy Now Online: P355TMHxA

Buy Now Online: 5:2sFTOH 

Wellington Reporter May 2019

Wellington Reporter Discontinued Products | Greyhound Chromatography

Wellington Reporter Header

PRODUCT DISCONTINUED

P44DMHxS

Unfortunately, P44DMHxS (a mixture of perfluoro-4-4-dimethylhexane sulfonate and perfluoro-4-4-dimethylhexanoic acid) is being discontinued due to limited interest and a lack of inventory. However, these compounds are identified as minor components in our br-PFOSK/T-PFOS and T-PFOA reference standards respectively. We apologize for any inconvenience this may cause and appreciate your understanding. 

Wellington Reporter Extract

 

 

 

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About Wellington Laboratories

For Over 35 years Wellington Laboratories Inc. has been internationally recognised as a trusted source of high quality reference standard solutions for use in environmental/analytical testing and toxicological research. Wellington Laboratories offers an extensive inventory of individual certified reference standards and solution mixtures of native and mass-labelled halogenated organic compounds including polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, polychlorinated biphenyls, halogenated flame retardants and perfluorinated compounds. Wellington Laboratories also offer a variety of calibration sets and support solutions designed to be used for common regulatory methods or modified in-house methods.

Wellington’s Reference Standards are used mainly in Environmental/analytical testing and toxicological research. Wellington offers an extensive inventory of individual certified reference standards and solution mixtures of native and mass-labelled halogenated organic compounds including polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, polychlorinated biphenyls, halogenated flame retardants and perfluoronated compounds. Wellington also offer a variety of calibration sets and support solutions designed to be used for common regulatory methods of modified in-house methods.

Wellington Laboratories are committed to the distribution of quality products as well as the maintenance of excellent customer service. In fact, in order to provide your customers with the best possible service, Wellington have three ISO certifications (ISO 9001:2008, ISO/IEC 17025:2005, and ISO Guide 34:2009) which cover all aspects of planning, production, testing, distribution, and post-distribution service. These certifications allow Wellington Laboratories to monitor and maintain the highest level of quality and service and also allow their customers to satisfy the requirements of their own ISO certifications.

Wellington’s ISO/IEC 17025:2005 accreditation has been certified by the Canadian Association for Laboratory Accreditation Inc. (CALA) the scope is available for review on the CALA Directory of Accredited Laboratories (http://www.cala.ca).

Similarly, Wellington’s ISO Guide 34:2009 accreditation has been certified by ANSI-ASQ National Accreditation Board (ANAB), the certificate and scope are available on their website (http://anab.org/).

We are able to supply hard copies of any of the ISO certificates for yourself and your customers.

 

Full Range of Wellington Laboratories' Products

Contact Us

  Tel: +44 (0) 151 649 4000   Fax:  +44 (0) 151 649 4001

 Web: www.greyhoundchrom.com

 

Email: info@greyhoundchrom.com

 

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