Micrometer syringe

Micrometer syringe pipettes are fitted with a micrometer head which operates the plunger of the syringe, and when fitted with a stainless steel needle tip can be used for the dropwise addition of liquid the volume added is recorded by the micrometer. 

Figure 7. Spreading a film with a micrometer syringe. The film balance and its case are housed inside a temperature controDed cabinet.

Monolayer films are usually spread from a dilute solution in an appropriate volatile and highly purified solvent. Small droplets of solution are spotted at 40 or SO points on the clean subphase surface using a micrometer syringe. Adequate time, say 20 min, must be allowed for the surfactant film to spread evenly and also for the solvent to evaporate completely. Since certain solvents are retained in some... 

Procedure. To form a BLM, a small amount (.— 0.005 ml.) of lipid solution was applied via a Teflon capillary attached to a micrometer syringe. The formation characteristics leading to the black state were observed under reflected light at 20-40 X magnification. Other precautions that should be exercised are essentially those described previously (10). The bifacial tension of BLM was measured as follows. After the membrane had become completely black (except at the Plateau-Gibbs border), the infusion-withdrawal pump was started. The pressure difference across the BLM was continuously monitored and reached a maximum when the membrane was hemispherical. The interfacial tension was calculated from this point using Equation 3. 

Total nitrogen estimations were performed on the polyamino acid solutions before hydrolysis by a semimicro-Kjeldahl technique. Amide-like nitrogen was measured on samples of the polyamino acids after hydrolysis in 2N HC1 for 2 hours under reflux by the Conway microdiffusion technique using No. 2 units. Ammonia was absorbed in 0.5% boric acid solution and titrated with 0.01 N HC1 using a micrometer syringe. 

A suitable tip which has been carefully ground smooth used in conjunction with a micrometer syringe burette gives a very convenient... 

The measurement of the amount put on is probably best made by means of an Agla micrometer syringe 1 this measures down to one ten-thousandth of a c.c. A simple dropping pipette with a teat and a fine tip is somewhat more convenient, and accurate to about 2 per cent. with this a slight correction needs to be made for the evaporation of the more volatile solvents.2... 

The question of the existence of an adsorbed gas film on liquids has some bearing on the drop-weight method. A micro-method in which drops are delivered from a micrometer syringe has been used. ... 

A second example illustrates how to obtain an end-point that was missed. To determine the concentration of a weak base compound, a known excess of HCl was added to a solution of the compound, and a micrometer syringe buret, was used to back-titrate the excess acid with standard base. Unfortunately the student doing the titration did not take small increments near the inflection point (which was not very pronounced, in any case), and the result shown in Figure 20-8 was obtained. 

A fresh interfacial area needs to be created directly before depositing the mono-layer material. This can be achieved by sweeping the surface remnants of a previous experiment or inadvertant surface-active Impurities are collected by compressing the area, followed by suction of the reduced area. This manipulation can be repeated several times. Preferably after compression the surface pressure should be 0.1 mN m". In most cases, some tens of a pf of the spreading solution Is supplied by using a micrometer syringe. In the case of a liquid-gas interface, a drop of the spreading solution may Just be deposited on the surface, provided the monolayer material is insoluble in the liquid phase. However, in the case of... 

Glynne Jones, G.D. and Lowe, II.J. (1956). An inexpensive addition lo a micrometer Syringe Ibr the semi-automatic production of small measured drops. Laboratory Practice 5. 69. 

The OMS solution was prepared in benzene and added to the surface by an Agla micrometer syringe, Two to 3 min were allowed for evaporation of the solvent before readings were taken. 

Monolayers were spread from an Agla micrometer syringe. Mixed monolayers consisted of 0.045 mg gliadin and 0.005 mg surfactant. For the penetration studies 5 X 10 4 mg quantities of surfactants were injected with a Hamilton microliter syringe under gliadin monolayers (5 X... 

A captive air (or other gas) bubble is formed in the liquid contacting with the solid by means of an inverted micrometer syringe beneath the substrate which is kept in the test liquid. The contact angle is measured by means of a goniometer microscope or video camera. In this method, the solid-vapor interface is in equilibrium with the saturated vapor... 

An Agla micrometer syringe outfit, developed by the Wellcome Research Laboratories of England, is used for the injections. Needles can be pulled from glass capillary tubing with a Brinkman needle puller or by hand. These needles are placed over stainless steel needles and sealed with paraffin. The whole unit (micrometer, syringe, and needle) is then secured to a ring-stand with jaw clamps cushioned with foam rubber. 

Our experimental set-up is described in detail in Ref. 34. The porous-plate measuring cell was placed inside a ther-mostated jacket on a Carl Zeiss Axiovert 100 inverted microscope. The film was viewed and recorded with a CCD video camera and a VCR. The capillary pressure was controlled by adjusting the height of the solution, using a manually operated micrometer syringe or by adjusting the air pressure inside the cell. 

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