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What else can I help you with?
Where can you buy an HPLC autosampler syringe in Ontario Canada?
Many stores in Ontario Canada allow one to buy an HPLC autosampler syringe. The Hamilton Company is an example that provides these syringes to Ontario.
What instrument measures gases in closed containers?
On 2 aspects, 1. A pressure sensor, can link to amount of gas formed, and a GC autosampler can work for qualitation, or quantitation
Can vacuum pressure be created inside an HPLC autosampler vial because of over-tightenning of cap or over-filling of vial?
I have worked as a development scientist for over 10 years now. This mythical vacuum has been talked about for many years. It is theoretically possible for a slight vacuum to form if the conditions are just right. For the conditions to apply you need to have: A sample vial filled beyond the top fill line (partially coming out of the vial with surface tension holding it in) and a very tight cap so that there is almost no air in the vial. Most autosamplers cannot withdraw more than 100 µL at any given time and the top fill line of a vial is 1.5 mL, the headspace is effectively .2 mL give or take a bit. A 100µL withdraw would create a pressure in the vial of ~ .6 atm until the syringe exits the vial upon which it would equalize. It is very unlikely this would cause an appreciable difference in the injection volume. If you're looking for sources of error, it's much more likely that there is an issue with the lamp intensity causing the variability. I have seen the vacuum problem before, but it's always in very extenuating circumstances.
What is the use of gas chromatography in food industry?
Chromatographydates to 1903 in the work of the Russian scientist, Mikhail Semenovich Tswett. Germangraduate student Fritz Priordeveloped solid state gas chromatography in 1947. Archer John Porter Martin, who was awarded the Nobel Prize for his work in developing liquid-liquid (1941) and paper (1944) chromatography, laid the foundation for the development of gas chromatography and he later produced liquid-gas chromatography (1950). Erika Cremerlaid the groundwork, and oversaw much of Prior's work.[edit]GC analysisA gas chromatograph is a chemical analysis instrument for separating chemicals in a complex sample. A gas chromatograph uses a flow-through narrow tube known as the column, through which different chemical constituents of a sample pass in a gas stream (carrier gas, mobile phase) at different rates depending on their various chemical and physical properties and their interaction with a specific column filling, called the stationary phase. As the chemicals exit the end of the column, they are detected and identified electronically. The function of the stationary phase in the column is to separate different components, causing each one to exit the column at a different time (retention time). Other parameters that can be used to alter the order or time of retention are the carrier gas flow rate, column length and the temperature.In a GC analysis, a known volume of gaseous or liquid analyte is injected into the "entrance" (head) of the column, usually using a microsyringe(or, solid phase microextraction fibers, or a gas source switching system). As the carrier gas sweeps the analyte molecules through the column, this motion is inhibited by the adsorption of the analyte moleculeseither onto the column walls or onto packing materials in the column. The rate at which the molecules progress along the column depends on the strength of adsorption, which in turn depends on the type of molecule and on the stationary phase materials. Since each type of molecule has a different rate of progression, the various components of the analyte mixture are separated as they progress along the column and reach the end of the column at different times (retention time). A detector is used to monitor the outlet stream from the column; thus, the time at which each component reaches the outlet and the amount of that component can be determined. Generally, substances are identified (qualitatively) by the order in which they emerge (elute) from the column and by the retention time of the analyte in the column.[edit]Physical componentsDiagram of a gas chromatograph.[edit]AutosamplersThe autosampler provides the means to introduce a sample automatically into the inlets. Manual insertion of the sample is possible but is no longer common. Automatic insertion provides better reproducibility and time-optimization.Different kinds of autosamplers exist. Autosamplers can be classified in relation to sample capacity (auto-injectors vs. autosamplers, where auto-injectors can work a small number of samples), to robotic technologies (XYZ robot vs. rotating robot - the most common), or to analysis:LiquidStatic head-space by syringe technologyDynamic head-space by transfer-line technologySolid phase microextraction (SPME)Traditionally autosampler manufacturers are different from GC manufacturers and currently no GC manufacturer offers a complete range of autosamplers. Historically, the countries most active in autosampler technology development are the United States, Italy, Switzerland, and the United Kingdom.[edit]InletsThe column inlet (or injector) provides the means to introduce a sample into a continuous flow of carrier gas. The inlet is a piece of hardware attached to the column head.Common inlet types are:S/SL (split/splitless) injector; a sample is introduced into a heated small chamber via a syringe through a septum - the heat facilitates volatilizationof the sample and sample matrix. The carrier gas then either sweeps the entirety (splitless mode) or a portion (split mode) of the sample into the column. In split mode, a part of the sample/carrier gas mixture in the injection chamber is exhausted through the split vent. Split injection is preferred when working with samples with high analyte concentrations (>0.1%) whereas splitless injection is best suited for trace analysis with low amounts of analytes (
