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gas chromatographt (GC) and High Performance Liquid Chromatography (HPLC) are different , and to understand why you must think about what chromatography is:
Chromatography in its simplest form is like putting ink on blotting paper and watching the colours separate.
Liquid chromatoraphy uses a "column" which is made from bare or bonded silica, it separates a mixture of compounds by how polar they are. You can use a gradient of different solvents.
GC also uses a column, but it is a capillary column and instead of using a liquid to carry your mixture which needs to be separated it uses a carrier gas, like nitrogen. You can vary the temperatures in both LC and GC to aid better resolution.
GC is used for more volatile compounds and LC is used more less volatile. HPLC usually refers to reversed phase, normal phase is where the column is vare silica which is very polar. Bonded silica is bonded with hydrocarbons which is non polar.
The thing to remember is that "like attracts like" so if the column in non polar, the compound to elute first will be the most polar.
To summarise, they are both separation techniques, one uses gas and the other liquid. You would choose which one to uese depending on how volatile the compounds which you want to separate are.
Vishal Bobade NCL,Pune
What else can I help you with?
What is difference between high pressure liquid chromatography and high performance lequid chromatography?
High pressure liquid chromatography (HPLC) and high performance liquid chromatography (HPLC) are often used interchangeably. HPLC refers to modern liquid chromatography systems with high resolution and efficiency, while high pressure liquid chromatography specifically highlights the use of higher pressures in the system to improve separation and speed. Both terms generally refer to the same chromatographic technique.
What is difference between isocratic and gradient hplc?
In isocratic HPLC, the mobile phase composition remains constant throughout the entire run, leading to constant elution times for all analytes. In gradient HPLC, the mobile phase composition is changed during the run, allowing for better separation of complex mixtures by adjusting the solvent strength over time.
What type of species can be separated by HPLC but not by gas liquid chromatography?
mixture of enantiomers can be separated by HPLC
What is difference between specificity and selectivity in hplc method validation?
Specificity refers to the ability of an analytical method to accurately measure the analyte of interest in the presence of potential interfering substances. Selectivity, on the other hand, refers to the ability of the method to only detect the analyte of interest while ignoring any other components present in the sample. Both are important parameters in HPLC method validation to ensure accurate and reliable results.
Can melamine detect by HPLC?
Yes, melamine can be detected by HPLC (High Performance Liquid Chromatography). HPLC is a common analytical technique used to separate and quantify compounds in a mixture, including melamine. Detection methods such as UV-Vis spectroscopy or mass spectrometry can be used in conjunction with HPLC to identify and quantify melamine accurately.
What is Difference Between HPLC UV detector Spectrophotometer uv detector?
HPLC UV detector is a component used in high-performance liquid chromatography (HPLC) to monitor eluent absorbance, while a spectrophotometer UV detector is a standalone instrument used to measure the absorption of light at different wavelengths. HPLC UV detectors are specifically tailored for chromatography applications, whereas spectrophotometer UV detectors are more versatile and used for various analytical purposes.
What are the key differences between reverse phase and normal phase HPLC techniques?
Reverse phase and normal phase HPLC techniques differ primarily in the polarity of the stationary phase and mobile phase. In reverse phase HPLC, the stationary phase is nonpolar and the mobile phase is polar, while in normal phase HPLC, the stationary phase is polar and the mobile phase is nonpolar. This polarity difference affects the retention and separation of compounds in the sample.
What is difference between high pressure liquid chromatography and high performance lequid chromatography?
High pressure liquid chromatography (HPLC) and high performance liquid chromatography (HPLC) are often used interchangeably. HPLC refers to modern liquid chromatography systems with high resolution and efficiency, while high pressure liquid chromatography specifically highlights the use of higher pressures in the system to improve separation and speed. Both terms generally refer to the same chromatographic technique.
What are the key differences between HPLC reverse phase and normal phase chromatography techniques?
In reverse phase HPLC, the stationary phase is nonpolar and the mobile phase is polar, while in normal phase HPLC, the stationary phase is polar and the mobile phase is nonpolar. This difference in polarity affects how compounds interact with the stationary phase, leading to variations in separation and elution times.
How do you use resolution factor in HPLC?
The resolution factor in HPLC is used to quantify the degree of separation between two adjacent peaks on a chromatogram. It is calculated by dividing the difference in retention times of the two peaks by the sum of their peak widths. A higher resolution factor indicates better separation between the peaks.
What are the key differences between HPLC normal phase and reverse phase chromatography techniques?
In normal phase HPLC, the stationary phase is polar and the mobile phase is nonpolar, while in reverse phase HPLC, the stationary phase is nonpolar and the mobile phase is polar. This difference in polarity affects how compounds interact with the stationary phase, leading to different separation mechanisms and selectivity in each technique.
What are the key differences between normal phase HPLC and reverse phase HPLC in terms of their separation mechanisms and applications?
Normal phase HPLC separates compounds based on their polarity, with the stationary phase being polar and the mobile phase being nonpolar. Reverse phase HPLC separates compounds based on their hydrophobicity, with the stationary phase being nonpolar and the mobile phase being polar. Normal phase HPLC is typically used for separating polar compounds, while reverse phase HPLC is used for separating nonpolar compounds.
How do you distinguised np-hplc and rp-hplc?
NP-HPLC is "Normal Phase" HPLC, wherein the solvents used are less polar than the substrate in the HPLC column (e.g. using hexane or dichloromethane with a silica HPLC column). RP-HPLC is "Reverse-Phase" HPLC, wherein the solvents used are more polar than the substrate in the HPLC column (e.g. using Water and Methanol with a octadecylsilane (ODS or C18) column).
What is difference between isocratic and gradient hplc?
In isocratic HPLC, the mobile phase composition remains constant throughout the entire run, leading to constant elution times for all analytes. In gradient HPLC, the mobile phase composition is changed during the run, allowing for better separation of complex mixtures by adjusting the solvent strength over time.
What is difference bet GLC and HPLC?
GLC has a stationary liquid phase and gas moving phase HPLC had a stationary solid phase and liquid moving phase HPLC is done under high pressure. HPLC can be used for thermally unstable compounds as opposed to GLC HPLC can be used for polar or low volatile compounds as opposed to GLC
Retention time calculation for hplc?
why RT was shifting & how to RT calculation in HPLC
What type of species can be separated by HPLC but not by gas liquid chromatography?
mixture of enantiomers can be separated by HPLC
