Solid phase extraction device

• US 5,368,729 A
• Filed: 07/23/1993
• Issued: 11/29/1994
• Est. Priority Date: 07/23/1993
• Status: Expired due to Term

• Current Assignee: Whatman Ltd. (United Kingdom) (General Electric Co. (Italy))
• Original Assignee: Whatman, Inc. (General Electric Co. (Italy))
• Inventors: Stefkovich, Joseph, Liu, Alfonso
• Primary Examiner(s): Spear, Frank
• Assistant Examiner(s): Fortuna, Ana M.
• Application Number:
  US08/097,396
• Time in Patent Office: 494 Days
• Field of Search: 210/502.1, 210/266, 210/282, 210/289, 210/295, 210/321.75, 210/321.84, 210/490, 210/453, 422/101, 436/178, 604/406
• US Class Current: 210/266
• CPC Class Codes: B01D 15/00 Separating processes involving the treatment of liquids with solid sorbents using liquid sorbents B01D11/00; ion exchange processes or materials, sorbent materials in general B01J, e.g. sorbents for chromatography B01J20/281; for investigating or analysing materials G01N30/00; Apparatus therefor
• CPC Class Codes: B01D 15/08 Selective adsorption, e.g. chromatography
• CPC Class Codes: B01D 61/00 Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor separation of gases or vapours by diffusion B01D53/22
• CPC Class Codes: B01D 61/18 Apparatus therefor

Abstract

A solid phase extraction device has a solvent-compatible permeable membrane with a bubble point greater than the normal operating pressure differential used and a sorbent material retained by two disks or frits so that when pressure is applied, the sample to be processed will pass through the membrane, but the membrane will not permit air to pass therethrough, and the sorbent remains wet throughout the process. The device has an input port and an output port and operates to maintain a pressure differential between the ports. Sorbent material is entrapped between two disks or frits. Located above the sorbent material is a support having a grid surface. The support prevents the frit from "riding up" the column of the barrel. Ultrasonically welded to the support is a solvent-compatible permeable membrane. The membrane is hermetically sealed to the support and the support is self-locked to the interior barrel of the device. When wetted, the membrane allows for the passage of matter, but prevents air from passing therethrough to the sorbent material. The sorbent material remains wet. With the sorbent material retained by the frits, the sorbent material will not escape to contaminate the filtrate.

Claims

1. In a hollow solid phase extraction device having an input port and an output port, sorbent-retaining means disposed between said input port and said output port, and a sorbent material entrapped within said sorbent retaining means, said device being operable to accept and maintain a pressure differential between said input port and said output port, the improvement comprising:

(i) a solvent-compatible permeable membrane having a bubble point greater than the normal operating pressure differential normally applied between said input port and said output port which allows solvent to pass through said membrane while precluding the passage of air therethrough, thereby preventing said sorbent material from drying out, and,

(ii) membrane support means supporting said membrane, said membrane support means being disposed upstream from said sorbent retaining means in an air-tight relationship with said interior of said extraction device.

2. The device of claim 1 wherein said solvent-compatible permeable membrane includes pores within a range of 0.2 and 0.002 micrometers.

3. The device of claim 2 wherein said solvent-compatible permeable membrane is composed of a polymeric or inorganic material.

4. The device of claim 3 wherein said membrane support means comprises molded polypropylene grid.