Abstract: A bent capillary flow cell with protruding end bulbs coaxial with centerline of an elongated center cylindrical section of capillary tubing. The bulbs provide a high light throughput entrance window for the cell. Light is piped along the elongated center section by total internal reflection at the outside surface of the cell wall. An external light absorbing band is placed in optical contact with outer surface of the cell wall over a transition cone region between the bulb and center cylindrical section of the cell. Each of the external light absorbing bands extend a short prescribed distance over the cylindrical wall to absorb light rays that would otherwise be light piped within the cell wall and have little exposure to the liquid in the cell.

Abstract: First liquid pumping apparatus for containing a first quantity of first liquid, second liquid pumping apparatus for containing a second quantity of second liquid and control apparatus for alternately connecting the first liquid pumping apparatus and second liquid pumping apparatus to pressurized liquid utilization apparatus and for causing the first and second liquid pumping apparatus to alternately deliver the respective liquids to the liquid utilization apparatus at a substantially constant flow or substantially constant pressure; the first and second liquids may be the same liquid or different liquids.

Abstract: A pump (20) has a housing (22) consisting of top (24), bottom (26), sides (28) and (30) and ends (32), (34), and (36) defining a plenum (38). An axially extending passage (40) is formed by the ends (32) and (34), through which flexible tubing (42) passes. The plenum (38) is connected to the passage (40). A pressure block (44) is slideably positioned in the plenum (38) for movement toward and away from the flexible tubing (42). The pressure block (44) has a rectangular opening (46), which receives a circular bearing (48) and a circular cam (50) which is eccentrically mounted on shaft (52). Conventional ball valves (54) and (56) are provided in the flexible tubing (42) above and below the pressure block (44). The lifetime of the tubing is substantially enhanced if the pressure block (24) depresses the tubing (42 ) no more than half of its inside diameter. When this limitation is followed, no creasing or similar localized severe distortion of the tubing (42) takes place.

Abstract: A continuous flow peptide synthesizer (10) has reservoirs (12-42) for amino acid derivatives and reservoirs (154-156 and 161-167) for peptide synthesis reagents and solvents. A column (44) has column segments (224, 226, 228) forming stacked interconnected chambers for holding peptide synthesis polymeric resin supports (260). Each of the amino acid derivative reservoirs (12-42) and the reagent and solvent reservoirs (152-154 and 161-167) are connected through a separate controllable valve (46-76, 154-156 or 182-194) to the column (44). A pressurized source (106) of helium or other inert gas is provided for transferring the amino acid derivatives, reagents and solvents to the column (44). The column segments (224) are also used in a vessel (270) for confining the polymeric resin supports (260) in the vessel during cleavage of the peptides from the supports (260).

Abstract: A solvent delivery system (10) has first and second pistons (92, 94) and cylinders (58, 68) connected to first and second cams (110, 112). The cams (110, 112) each have a ramped portion (150, 162) and an abrupt step (152, 164). The first cylinder (58) is connected to solenoid valves (44, 46, 48) to fill the first cylinder with solvent components during movement of cam follower (104) along ramped portion (150) of the first cam (110). Spring (140) urges the first piston (92) forward into first cylinder (58). Movement of the cam follower (104) over the step (152) of the cam (110) moves the piston (92) forward abruptly to force the solvent components from cylinder (58) into second cylinder (68). Spring (178) urges piston (94) back in cylinder (68). The second cam (112) is reversed relative to first cam (110). Movement of cam follower (106) over abrupt step (164) of second cam (112) moves second piston (94) back abruptly in cylinder (68) to receive and mix the solvent components in the cylinder (68).

Abstract: An apparatus (10) for proportioning and mixing liquid components of a solvent has a chamber (12) with a rotatable piston (24) mounted in the chamber. The chamber has a plurality of liquid component inlets (18, 20 and 22). Rotatable piston (24) has a notched portion (30). Relative lengths of time the notched portion (30) is opposite the inlets (18, 20 and 22) determine the proportion of liquid components supplied at each inlet port (18, 20 and 22) in the solvent mixture. Rotation of the piston (24) in the chamber (12) mixes the liquid components introduced through the inlet ports (18, 20 and 22). Stepper motor (32) is controlled by microprocessor (52) driven control system (50) to position the notched portion (30) at the inlet ports (18, 20 and 22) for variable lengths of time.

Abstract: A multichannel pump wherein the flow rate through each channel can be independently adjusted. In one embodiment there is a frame composed of upper and lower disc-shaped members which support a shaft in the center and a plurality of tube holders around the periphery. An eccentric cam is carried on the shaft and sequentially contacts resiliently deformable tubes in the respective tube holders. Each tube holder is independently adjustable toward and away from the path of travel of the cam and each can be removed for replacement or repair without affecting operation of the remainder of the apparatus. Also included are structures permitting the use of tubing having a low degree of elasticity, such as Teflon and the like. In another embodiment there is one or more cassette-like pumping units each of which contains two independently adjustable channels. The cassette-like units are so constructed that any reasonable number of the units can be combined to provide a multichannel pump having as many channels as needed.