Absorbent Pads
For Uniform Wicking and Absorbency in Diagnostic Tests
Sample pads and absorbent sinks are used in lateral flow diagnostic assays to draw (wick) the sample from one side of the analytical membrane to the other. Depending on the assay, the selection of the sample pad and wick may or may not be of the same material. At Pall, we have a variety of materials in various thicknesses, absorbencies and wick rates to meet your assay needs.
Sample Pads
When selecting a material to be used for a sample pad, two parameters are of critical importance – purity and consistency. Made of 100% pure cellulose fibers, our family of absorbent sample pads yields uniform sample absorption and wicking rates. The pure nature of the material is ideal for diagnostic assays that are extremely sensitive to the presence of interfering substances. Consistency is facilitated by the naturally hydrophilic nature of the material which ensures rapid wetting, consistent wicking rate, and uniform delivery of the sample to the conjugate pad. Additionally, the low protein binding nature of our absorbent sample pads ensure that the sensitivity of the assay is maintained and that there is minimal loss of target analyte.
We also offer glass fiber, polyester and blended materials if purity is less of a concern in your assay.
Absorbent Sinks
Absorbent sinks are incorporated at the end of the lateral flow strip to act as a reservoir for the sample after it has traveled through the strip. Typically constructed of either glass fiber or cellulose materials, the absorbent sinks also help to control the flow rate of the overall assay. Our hydrophilic materials ensure that a consistent flow rate is maintained across the test strip which aids in maintaining assay sensitivity.
Applications
- Sample pad
- Reaction matrices
- Absorbent sink
- Sample reservoir
- Membrane supports
Sealing
- Mechanical
- Adhesive
- Lamination
- Insert molding
Typical Membrane Characteristics
Grade | Base Material | Nominal Micron Rating (µm) | Thickness (mils) | Thickness (µm) | Typical Basis Weight (gm/2) |
|---|---|---|---|---|---|
| 111 | Cellulose and rayon blend |
35 | 12.0-18.0 | 304.8-457.2 | 63.3-77.3 |
| 113 | 100% pure cellulose fibers |
3 | 12.0-14.5 | 304.8-368.3 | 175.8-193.3 |
| 133 | 100% pure cellulose fibers |
18 | 30.0-35.0 | 762.0-889.0 | 277.7-302.3 |
| 165 | 100% pure cellulose fibers |
25 | 66.0-77.0 | 1676.4-1955.8 | 414.8-464.0 |
| 197 | 100% pure cellulose fibers |
14 | 92.0-102.0 | 2336.8-2590.8 | 681.9-724.1 |
| 8975 | Borosilicate glass fiber with PVA binder |
N/A | 9.0-13.0 | 228.6-330.2 | 49.1 |
| 8964 | Borosilicate glass fiber with PVA binder |
N/A | 14.0-20.0 | 355.6-508.0 | 75.1 |
| 8301 | Cellulose and synthetic blend with PVA binder |
171 | 14.0-17.5 | 365.0-445.0 | 50.0 |
Typical Performance Characteristics
| Grade | Base Material | Average Wicking Rate (sec/3 cm) | Water Absorption Capacity (µL/cm2) |
|---|---|---|---|
| 111 | Cellulose and rayon blend | 10 | 40 |
| 113 | 100% pure cellulose fibers | 169 | 30 |
| 133 | 100% pure cellulose fibers | 39 | 39 |
| 165 | 100% pure cellulose fibers | 7.9 | 161 |
| 197 | 100% pure cellulose fibers | 13 | 202 |
| 8975 | Borosilicate glass fiber with PVA binder | 156 | 19 |
| 8964 | Borosilicate glass fiber with PVA binder | 141 | 54 |
| 8301 | Cellulose and synthetic blend with PVA binder | 226 | 28 |
Custom roll, sheet, and disc sizes available upon request. Please contact your local sales representative for additional information.
| Part Number | Description | Pkg |
|---|---|---|
| S70006 | Cellulose Absorbent Pad 111, 8" x 10" sheet | 1/pkg |
| S70007 | Cellulose Absorbent Pad 113, 8" x 10" sheet | 1/pkg |
| S70008 | Cellulose Absorbent Pad 133, 8" x 10" sheet | 1/pkg |
| S70009 | Cellulose Absorbent Pad 165, 8" x 10" sheet | 1/pkg |
| S70010 | Cellulose Absorbent Pad 197, 8" x 10" sheet | 1/pkg |
| SMC0N75 | Conjugate Pad Type 8975, 8" x 10" sheet | 1/pkg |
| SMC0N64 | Conjugate Pad Type 8964, 8" x 10" sheet | 1/pkg |
| SMC0N01 | Conjugate Pad Type 8301, 8" x 10" sheet | 1/pkg |


