Teflon Sleeve

A hydrolysis unit is constructed using the commercially available glassware shown in Figure 2. The collection funnel should be calibrated and marked for volumes of 35 and 85 mL. All 20/40-glass joints of the hydrolysis unit should be assembled with Teflon sleeves and secured with spring clamps to prevent loss of the volatile EMA and HEMA analytes. 

Teflon sleeves are used to assure the vacuum tight connection between the ground joints subjected to heat. The checkers used clear-seal joints in all of the glass connections. 

Ground glass joints were connected using Teflon sleeves or a chlorofluorocarbon stopcock grease. 

Figure 7.12. Apparatus for extracting organic solutes from water. (A) 5-liter reservoir, (B) glass wool plugs, (C) 24/40 ground glass joint with Teflon sleeve,...

Teflon sleeves are useful to keep the joints from freezing. 

Figure 5.42 Flow cell for a selective-ion electrode A, sensor electrode B, reference electrode C, solution ground D, sensing membrane E, Teflon sleeve F, Plexiglas cap G, washer H, sample inlet flow /, sample outlet flow J, magnetic stirring bar K, potentiometer L, solution outlet.

The apparatus is then completely assembled, using a Teflon sleeve between the condenser and reaction-vessel neck. Upon removal from the dry-box, the loaded apparatus is immersed in a silicone-oil bath at room temperature and secured with a sturdy clamp. The nitrogen line is connected to the apparatus, and nitrogen is introduced at a minimal flow rate. The silicone-oil bath is heated by a magnetic-stirrer hot plate. The contents of the reaction vessel are then agitated at a high rate, and the temperature of the oil bath is slowly elevated to 290-300°C. 

Teflon items (Teflon stopcock plugs, rotary valve plugs, and Teflon sleeves) should be wiped off with some acetone (using a Kimwipe) before being assembled for use. 

There is one other substitute for stopcock grease on standard taper joints the Teflon sleeve. These sleeves are like socks for your joints. Because they are made of Teflon, they are not attacked by solvents, alkalines, and most other chemicals. Thus, they are wonderful for items like solvent flasks which are under constant fume or chemical contact. However, they are not capable of maintaining a static vacuum and should not be used for vacuum work. Thin Teflon sleeves are less expensive, but cannot take physical abuse. Heavier Teflon sleeves have a greater initial cost, but can be used over and over. 

The core experiments with Kern River oil were performed using sandpacks (25.4 cm by 3.7 cm) made from unconsolidated field core. The core material was packed into Teflon sleeves with Teflon end caps and then placed into a Hassler type core holder. Before packing, the sand was cleaned by Soxhlet extraction with toluene and was not fired. Otherwise, the procedure was similar to that for saturating the consolidated Berea sandstone cores. 

Quickfit joints on reaction flasks should be lined with Teflon sleeves. This is especially important when fine metal dispersions are used, which may otherwise seep through the joints and cause a potential fire hazard. 

A PE-Sciex API-I lonSpray mass spectrometer (PE-Sciex, Thornhill, Ontario, Canada) was used to acquire all mass spectra. The Sciex API-Ill mass spectrometer and Integral micro analytical workstation were coupled through a Im piece of fused silica tubing (75 im i.d.) at the exit of the capillary flow cell detector using a 250pm i.d. teflon sleeve as described previously (8). The source... 

Fig. 16.2. Schematic of a capillary column, in which the MIP particles were held by closing the ends of the capillary with poly(acrylamide) plugs. The MIP containing part of the capillary was connected to an open, buffer-filled capillary via a teflon sleeve. Reprinted from Ref. [62] Copyright (1997), with permission from Marcel Dekker, Inc.

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