Syringe pipets

The quality of apparatus is crucial. The quality of the pipets directly affects the reliability of the analytical information. It is necessary to use measuring pipets of high quality for reliable measures of volume, e.g., clinical, serological pipets, micropipets, syringe pipets. Syringe pipets must be used for measurement of microliter volumes. In volumetric analysis more reliable burets are necessary. For small quantities of sample, micro- and ultramicro-micrometer burets are recommended. Only well-calibrated pipets and burets will assure the accuracy of volume determination. 

The above syringe pipets are useful for accurate delivery of viscous solutions or volatile solvents with these materials the drainage film would be a problem in conventional pipets. Syringe pipets are well suited to rapid delivery and also for thorough mixing of the delivered solution with another solution as a result of the rapid delivery. 

Common types of pipets and syringes (a) transfer pipet (b) measuring pipet (c) digital pipet (d) syringe. 

Heber, m. siphon pipet(te) syringe lifter lever jack (Anat.) levator, -barometer, m. siphon barometer, -haartohr, n. capillary siphon. 

The sample dissolved in a weak (nonpolar for siliea gel), volatile solvent is applied as a narrow band across the plate. Manual applieation can be aehieved with a pipet or syringe gnided by a ruler, or roimd spots ean be placed close together, side by side, in a line. Sample applieation instruments are available commercially, e.g., a meehan-ical streaker from Analtech and an antomated spray-on apparatus from CAMAG. 

Electronic analytical balance Volumetric flasks 100- to 1000-mL Volumetric glass pipets, various sizes Pasteur pipets, 5.75- and 9-in lengths Refrigerated centrifuge Nalgene centrifuge bottle, 250-mL Disposable syringes, 5-cm ... 

The method above, however, is not suitable when one needs a precise study of the vertical distribution of pesticides. Generally, the concentration of pesticides in paddy sediment is highest at the surface. Special care is required to avoid contamination with surface soil when the sediment is collected. The sediment core should be collected in two stages. First, a pipe with a diameter greater than that of the core sampler is inserted in the sediment and then water inside the pipe is removed gently with a syringe, pipet, etc. Next, a layer of surface soil (1-3 cm) is taken with a spatula or a trowel and then subsurface soil is collected with a core sampler to the desired depth see also Figure 4. 

I Dispense samples, standards and controls Precision dispensing or pipetting of samples, standards and controls Z510 Master Laboratory Station, or ZI90 Precision Microlitre syringe head... 

It is convenient to measure out the hydrogen peroxide by a 10-ml. graduate or by a 10-ml. pipet actuated by a glass syringe connected via a ground-glass joint. 

A 250 ml flask with the equipment shown in Fig. 3.2 is flushed with argon.Then, 90 ml of the highly dried toluene are added with a syringe. Now are pipetted in under stirring ... 

Use a sheet of polyethyleneimine cellulose (PEI Cellulose), 50 x 200 mm, for chromatography. Mark the start about 15 mm away of the shorter side with a pencil. Apply the sample with a pipet or syringe. If larger volumes have to be used, apply them in several portions and/or a short line. 

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. 

Sample Aspiration aitd Dispensing. Precisely metered amounts of the sample have to be aspirated rapidly and without allowing intersample contamination, known as sample carry-over. Generally, pipetting is accomplished by motor-driven syringes connected through a fluid line to a thin aspiration probe (see Fig. I)... 

Assembled hypodermic syringe in metal pipetting holder... 

Continuous syringe pipet, Aloe, St. Louis, Missouri Aupette, Clay Adams, New York. 

Fig. 6. Automatic pipetting machines. Two types of automatic pipetting machines are shown (a) Brewer and (b) Volustat (Fisher Scientific Co.). These machines serve the same function as the hand-operated syringe pipets but eliminate the tedium of multiple manual reagent additions. They may be operated by foot switch to deliver a single sample or may be operated in a continuous fashion to deliver samples at a rate of slightly more than forty five per minute. They may be successfully run by unskilled operators.

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