Submitted by anthias on
The installation of a capillary column into a modern gas chromatograph requires precise positioning of the column into both the inlet/injection port and the detector to obtain optimum analytical performance. Individual manufacturers have different requirements for the optimum insertion length and positioning of the column which should be checked from the relevant instrument operating manual.
Submitted by anthias on
The installation of a capillary column into a modern gas chromatograph requires precise positioning of the column into both the inlet/injection port and the detector to obtain optimum analytical performance. Individual manufacturers have different requirements for the optimum insertion length and positioning of the column which should be checked from the relevant instrument operating manual.
Submitted by anthias on
Failing to identify a problem early can result in it possibly becoming a major problem with lots of down-time and costs involved in solving and fixing it. Many samples may also need to be re-analysed adding to costs, time, stress and customer satisfaction. Conversely, thinking that there is a problem when there isn't really one can also lead to all of these things with lots of tail-chasing and not really getting anywhere.
Submitted by anthias on
Most GC-MS vacuum systems comprise of a two-stage pumping arrangement - an initial low-vacuum, high capacity stage consisting of a rotary oil pump or diaphragm pump; and a second high stage, low capacity vacuum pump such as a diffusion or turbo-molecular pump. The first stage or low-vacuum pump requires maintenance to ensure optimum pumping performance. Two aspects that are often overlooked are the use of the ballast valve on the vacuum pump and replacement of the pump oil at the correct intervals.
Submitted by anthias on
Tips on connecting capillary columns together using the press-fit connector.
Submitted by anthias on
Knowing where your gas cylinders are located and regularly checking the contents is very important for any gas chromatographer when troubleshooting an instrument. People responsible for the cylinders go on holiday or leave and the first the instrument operators knows about it is when they run out of gas and then it is a major panic!
Submitted by anthias on
Most problems that occur in Gas Chromatography either gradually increase in severity over time or suddenly become a large issue, preventing further analysis by the instrument.
Random problems occurring infrequently are often ignored for long periods of time as the sample is simply re-analysed and the results are correct the second time. The problem itself can be hard to track down to determine the cause and then to provide a fix, as it isn't a continuous problem.
Submitted by anthias on
Splitless injections are used to transfer all of the injected analytes onto the analytical column for separation and detection and are therefore used for low concentration samples.
How do you determine the split open time?
Submitted by anthias on
Obtaining the best resolution for the method is critical for accurate qualitative and quantitative analysis, especially where chromatographic resolution is relied upon with standard GC detectors, as there is no MSD to take advantage of analytical resolution.
Submitted by anthias on
Sample introduction or the GC inlet parameters are very often overlooked when developing a GC or GC-MS method, but these parameters are so powerful that they can result in success or total failure of an application and as a result are also the main area for troubleshooting and maintenance within the GC system.