Splitless injection and the solvent effect

Grob, Konrad

doi:10.1002/jhrc.1240010112

Cited by 199 publications

(98 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A fused silica open tubular column (Hewlett-Packard ultra no. 2; 25 m x 0.31 mm i.d., 0.52-,m film thickness) was used, and samples were injected onto the column at 600C by means of a Grobtype splitless injector with a cold-trap technique (10). After injection, the column temperature was programmed from 120 to 2000C at 4°C/min.…”

Section: Resultsmentioning

confidence: 99%

Aminomalonic acid: identification in Escherichia coli and atherosclerotic plaque.

Buskirk¹,

Kirsch²,

Kleyer³

et al. 1984

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

Aminomalonic acid: identification in Escherichia coli and atherosclerotic plaque.

Buskirk¹,

Kirsch²,

Kleyer³

et al. 1984

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…In GC, the presence of lipids may cause problems in the injector and at the inlet of the column [81,82]. When the detection system is MS, contamination occurs in the ion source which affects the reliability and accuracy of the analysis [80].…”

Section: Clean-upmentioning

confidence: 99%

Supercritical fluid extraction of polyhalogenated pollutants from aquaculture and marine environmental samples: A review

García-Rodríguez

Carro-Díaz

Lorenzo-Ferreira³

2008

J of Separation Science

View full text Add to dashboard Cite

ReviewSupercritical fluid extraction of polyhalogenated pollutants from aquaculture and marine environmental samples: A review This article focuses on the state-of-the-art in sample preparation using supercritical fluid extraction (SFE), to monitor the content of polyhalogenated pollutants in aquaculture and marine environmental samples. Marine sediments and biological applications, including several types of samples matrices (fish, shellfish, seaweed and fish feed) and analyte groups (polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), polybrominated diphenylethers (PBDEs), polychlorinated dibenzop-dioxin (PCDD)/Fs and organochlorinated pesticide (OCPs)) are discussed with respect to SFE use and optimisation of conditions. We also discuss the great analytical potential of SFE, the integration of the extraction and clean-up steps for rapid sample processing justifying its use for routine work. The most recent SFE applications to the determination of these pollutants in marine environmental (biota and sediment) samples, published in the last 15 years, are reviewed.

show abstract

“…However, an injection of only 100 nl would require almost a 51-mm length of column just to contain the volume of the injected plug. If a separate liquid phase can exist at the temperature and pressure in use, the action of the mobile phase on a liquid plug will spread it into a flooded zone several meters in length [6,[10][11][12][13][14]. Solutes will, of course, be distributed over this entire flooded zone by the liquid solvent.…”

Section: Peak Focusing Mechanismsmentioning

confidence: 99%

“…Solvent trapping or focusing (that is, the solvent effect) is also possible in SFC [6,[11][12][13]. This may occur on any tube, uncoated or coated with stationary phase, by exactly the same mechanism occurring in GC.…”

Section: Peak Focusing Mechanismsmentioning

confidence: 99%

Injection techniques in SFC

Greibrokk¹,

Chester²

1999

Analusis

View full text Add to dashboard Cite

The objective of the injector is to transfer the whole sample or a predetermined fraction of the sample quantitatively to the column in the narrowest possible band. The first part of this objective, a quantitative transfer of all components, is not always obtained since sample discrimination occurs in some injection techniques in SFC as well as in GC. The second part of the objective, transfer in a narrow band, is a process which is affected by numerous factors, such as diffusion, linear velocity, temperature, solvents, loading and mixing efficiency, as well as phase transitions. Some of these factors also influence the first part of the objective, the yield of the transfer process. Injector temperatures exceeding room temperature are only used with solutes which need higher temperature to stay in solution, such as some polymers. Injection at high temperature should be performed with caution, since a solvent which starts to evaporate from a hot injector, before the valve is actuated, may result in sample loss and poor reproducibility.In most applications the sample is introduced as a relatively large (depending on the analyte concentration) liquid plug into the stream of mobile phase. Due to limited mixing, the major part of the sample often arrives at the column inlet dissolved in a liquid composed of the solvent partially mixed with the mobile phase. Thus, the transient elution strength of the sample may often be considerably higher than the elution strength of the mobile phase, and can adversely affect the peak shapes by flooding and dispersing the sample over the column inlet.It is well known that an exponential decay injection profile is obtained because of the laminar flow of the displacing mobile phase [1]. By moving the valve back to the load position from the inject position after a predetermined time, the solvent tail can be removed. The injection syringe should be removed first, since the pressure in the sample loop is released through the injection and waste ports when the valve is returned to the load position. With large sample loops the syringe might be pushed out of the port, or the plunger pushed out of the barrel, if the syringe is left in the injection port.By injecting very small volumes, using splitting or small sample loops, a more thorough mixing with the mobile phase can be achieved prior to the column. Currently the nominal volume of the smallest commercially available sample loop is 60 nl. However, small volume (< 100 nl) internal sample loops are difficult to manufacture with high accuracy, and the small volumes are difficult to maintain without changes, particularly with loops made from polymeric materials.Column overload is rarely caused by the mass of the solutes, but almost always by the amount of solvent. With a retention factor k = 1, the injected volume that produces 10 % peak broadening has been calculated to be 24 nl on a 50-µm-ID open-tubular column, and with a retention factor of 10, the volume was calculated to be 130 nl [2]. With an actual injection of 223 nl, 10 % loss of...

show abstract

Splitless injection and the solvent effect

Cited by 199 publications

References 18 publications

Aminomalonic acid: identification in Escherichia coli and atherosclerotic plaque.

Aminomalonic acid: identification in Escherichia coli and atherosclerotic plaque.

Supercritical fluid extraction of polyhalogenated pollutants from aquaculture and marine environmental samples: A review

Injection techniques in SFC

Contact Info

Product

Resources

About