Syringe microliter

The sample enters the GC at the injection port (Fig. 107). You use a microliter syringe to pierce the rubber septum and inject the sample onto the column. Don t stab yourself or anyone else with the needle. Remember, this is not dart night at the pub. Don t throw the syringe at the septum. There is a way to do this. 

Note To apply a solution of the analyte, the emitter can either be dipped into, or alternatively, a drop of 1-2 pi can be transferred onto the emitter by means of a microliter syringe. [46] The latter method exhibits better reproducibility and avoids contamination of the emitter holders. Special micromanipulators are available to handle the syringe, [15] but a skilled operator with some exercise can accomplish it manually. 

Fig. 8.7. FD probe, (a) Emitter holder of a JEOL FD probe tip, (b) a drop formed of 1-2 pi analyte solution placed onto the activated emitter by means of a microliter syringe.

Typically, PB was added to the appropriate buffer medium and used Immediately to minimize any possible loss of peroxygen content. OP reagents were transferred via microliter syringe to a second buffer solution as for PB, solutions were used Immediately after preparation. The reactions were Initiated by transferring an appropriate volume of PB solution (via Plpetman automatic pipettor) to a cuvette and then similarly adding OP ester solution to bring the total reaction volume to 3.00 cm. ... 

Many manufacturers now offer other sample injection systems compatible with the vacuum lock used for the solids probe. These include small (e.g., 75-ml) heatable batch inlet systems, usually accessible via syringe (gas syringe or GC microliter syringe for liquids), which can be particularly useful as inlets for mass reference compounds. Other probes are designed as flexible, easily removed connections to a gas chromatograph via some form of interface. 

Mark the start with a pencil on a PEI Cellulose sheet (dimensions as in Protocol 3.1.2) and apply the samples with a microliter syringe or a pipet. 

An electronic integrator is used to measure areas and retention times. Using a I microliter syringe, introduce a 0-5 microliter sample and start the Integrator. Under these conditions, acetone will elute at 0.5 to 0.6 minutes. NPL will elute at 18 ro 19 mins and EGDN will elute 1 to 2 mins after the NPL... 

Transfer 5-0 microliters of die sample (EGDN or liquid propellant), using a 10 microliter syringe to a 10 ml volumetric flask, dilute to volume with coned H2SO4 and mix... 

Microliter syringes, such as that in Figure 2-13, come in sizes from 1 to 500 p.L and have an accuracy and precision near 1%. When using a syringe, take up and discard several volumes of liquid to wash the glass walls and to remove air bubbles from the barrel. The steel needle is attacked by strong acid and will contaminate strongly acidic solutions with iron. 

Known concentrations of vapors can be prepared in the same way by injecting a known volume of a volatile liquid into the container using a microliter syringe normally used for liquid sample injection into a gas chromatograph. The density and molecular weight of the component are needed for the calculation. 

The sampling of liquid mixtures in GC is usually done by means of microliter syringes through a self-sealing silicone septum. The... 

A sample must be introduced onto the column in an efficient and reproducible manner. One of the most popular injectors is the syringe injector. The sample, in a microliter syringe, is injected through a neoprene/Teflon septum. This type of injection can be used at pressures up to 3000 psi. 

Solid-phase microextraction uses a 1-cm length of focused silica fiber, coated on the outer surface with a stationary phase and bonded to a stainless steel plunger holder that looks like a modified microliter syringe. The fused-silica fiber can be drawn into a hollow needle by using the plunger. In the first process, the coated fiber is exposed to the sample and the target analytes are extracted from the sample matrix into the coating. The fiber is then transferred to an instrument for desorption. The technique has been promoted by Pawliszyn (69). 

The TD-GC system can be calibrated by running tubes that are spiked with a known volume and concentration of a standard vapor-gas atmosphere of the analyte or injecting a known concentration and volume of a solution of the analyte by a microliter syringe into the sorbent bed and remove the solvent by purging the tube with helium or nitrogen. The solvent must be tailored to the method, so that it can be evaporated from the tube without removing the analytes. Methanol or pentane are good choices for Tenax TA. 

The sample injection system allows the injection of sample volumes from 1 to 500 pL. To prevent depressurization of the system, samples are injected through special six-way valves to which a sample loop has been attached. The sample is injected directly into the loop by means of a microliter syringe (filling position) while the eluent flows to the column. The eluent flow is then directed via the sample loop to the column when the valve is switched to the injection position. 

LPME Liquid-phase microextraction LLE with a minute amount of solvent, typically one microdrop, exposed at the tip of a microliter syringe, which is then withdrawn after extraction and injected into the GC Mostly GC-amenable analytes... 

AuCl (6.28 mg, 0.027 mmol) and a (solid) phosphorus ligand (0.027 mmol) were weighed into a reaction flask in air. The flask was evacuated for several minutes and charged with argon (3x). Nitromethane (2mL) was added. Liquid phosphorus ligands (0.027 mmol) were now added (either with microliter syringes or as stock solutions in nitromethane). Yellow suspensions were obtained which became... 

Other corrections that must be considered are the collection efficiency of the charcoal tube and the desorption efficiency of carbon disulfide for this specific solvent. TABLE 1 lists the recommended collection tube for each solvent, flow rate to be used in samplings, and desorption efficiency of many organic compounds. (6) The desorption efficiency of carbon disulfide with the charcoal tubes can be determined by injecting a known amount of solvent onto the charcoal. At least five charcoal tubes are sampled and the 100 mg portion removed and placed in a septum sealed vial. A concentration applicable to the threshold limit value of the organic solvent in question is injected onto the 100 mg of charcoal by piercing the septum cap with a microliter syringe. Several concentrations of solvent should be checked to determine the variation in desorption efficiency with solvent concentration. In like manner, standards are prepared by adding the same amount of solvent to the carbon disulfide solution in the vial. The standards are analyzed with the samples. The percent desorption efficiency (D.E.) is determined as ... 

Standard Preparations Transfer 10.0 mL of the Stock Lanthanum Solution into each of three 50-mL volumetric flasks. Using a microliter syringe, transfer 0.20 mL of the Stock Calcium Solution into the first flask, 0.40 mL into the... 

Sample Preparation Transfer about 250 mg of sample, accurately weighed, into a 30-mL beaker. While heating, dissolve the sample in 10 mL of alcohol, and quantitatively transfer the solution into a 25-mL volumetric flask. Wash the beaker with two 5-mL portions of alcohol, adding the washings to the flask, dilute to volume with alcohol, and mix. Transfer 5.0 mL of the Stock Lanthanum Solution to a second 25-mL volumetric flask. Using a microliter syringe, transfer 0.25 mL of the alcoholic solution of the sample to the second flask, dilute to volume with water, and mix. 

Standard Preparations Transfer 10.0 mL of the Stock Lanthanum Solution into each of three 100-mL volumetric flasks. Using a microliter syringe, transfer 0.20 mL of the Stock Sodium Solution to the first flask, 0.40 mL to the second flask, and 0.50 mL to the third flask. Dilute each flask to volume with water, and mix. The flasks contain 2.0, 4.0, and 5.0 (xg of sodium per milliliter, respectively. Prepare these solutions fresh daily. 

Ribbon Probe Compared to Quartz Tubes or Boats. Positioning of a wood or lignin sample is of paramount importance. Soluble lignins may be applied directly to the surface of the ribbon probe with a microliter syringe. A solution (2p ) of 10 mglp concentration is transferred to the ribbon probe. The solvent is evaporated either by air-drying or by heating the ribbon at an appropriate temperature. 

The insecticides are identified on the two different types of gas chromatographic columns by comparing the relative retention times of the recorded peaks of the samples with those of standards. If a closely eluting component interferes with the identification, a small amount of the suspected insecticide can be added to the sample which is injected into the column. This injection consists of a small measured amount of the insecticide standard drawn into a microliter syringe already charged with an aliquot of the sample extract. 

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