Molecular Traps


Molecular TrapsTM are highly activated molecular sieve packets designed to provide and maintain very low water levels in solvents and solutions. Originally designed for oligonucleotide synthesis, Molecular TrapsTM are a convenient, dust and lint free, way of adding molecular sieves to many solvents and organic solution. They can generally be used in any application where molecular sieves are utilized such as to dehydrate or maintain anhydrous solvents through repeated air exposures, or to remove small molecule contaminants and known breakdown products.
Use tested on ABI and MilliGen/PerSeptive DNA synthesizers, Molecular TrapsTM will maintain sub-50 ppm water levels in the acetonitrile and activator bottles directly on the instrument without fear of clogging valves or restrictors with sieve dust or pouch “fuzz”. Used directly in 4 liter solvent bottles, they provide a ready source of dry solvent for amidite dilution or other bench work, without the cost of discarding half-used bottles or buying many separate, small, bottles.
Molecular TrapsTM are available in three sizes for bottles from 50 ml through 4 liters. The chart below illustrates the dynamic water scavenging effect of these traps from acetonitrile samples “spiked” with large amounts of water.



Molecular TrapsTM are shipped fully activated, in evacuated foil packets and are ready for immediate use. Recommended usage is one large Molecular TrapTM, SP-MT10, for 1 to 4 liter bottles, one medium Molecular TrapTM, SP-MT5, for 250 ml - 1 Liter and one small Molecular TrapTM, SP-MT02, for 50 - 250 ml bottles. This usage assumes that the user has added the Molecular TrapTM to maintain a low water solvent or solution: to produce a low water solution from reagent grade material, at least two Molecular TrapsTM per bottle, and waiting at least 48 hours prior to use, is recommended, (see Capacity discussion below).

Quality Assurance:

Each manufactured lot is use tested, by Karl-Fisher determination, by quantifying water removal from a "spiked" sample of acetonitrile. For the customer, product quality is assured by examining the package before use: First, by verifying that the packet vacuum is intact; any loss of vacuum indicates air entry which would reduce the performance of the product. The second check is to look for any powder leakage inside the foil packet. When the sealing vacuum is applied, any weak point in the integrity of the Molecular TrapTM membrane will reveal itself by "leaking" powder into the foil packet.


The large Molecular TrapTM will irreversibly absorb up to 2 grams (2 ml) of water from solvents or solutions. The small Molecular TrapTM will absorb up to 400 milligrams (400 µl) of water. To gage water absorption; 1 microliter of water per liter of solvent = 1 ppm. HPLC grade acetonitrile is manufactured with 10 to 20 ppm of water, which is ca. 80 ul of water in a 4 liter bottle. The Molecular TrapTM must maintain water levels below 50 ppm, or 200 ul of water per 4 liters, to be effective for use in DNA synthesis.


Molecular TrapsTM, SP-MT02 (2 gram), SP-MT05 (5 gram), & SP-MT10 (10 gram) are made from ultrapure, electronics grade, microporous, hydrophobic membrane. The effective filtration of the membrane is 0.2µ. This membrane material is tested safe for long term exposure to the solvents detailed in the chart below. The bulk molecular sieves are pharmaceutical grade quality and are activated and processed before manufacture.

Oligonucleotide Synthesis

Molecular TrapsTM have been functionally tested for use in DNA synthesis on ABI model 392 & 394 synthesizers, and on Millign/PerSeptive Biosystems models
(Cyclone), 8700, 8800 and the 8900 (Expedite) synthesizers. Molecular TrapsTM are designed to be used directly on the instrument in the main acetonitrile bottle, the activator bottle and in the amidite bottles (8800).

Peptide Synthesis

Dimethylformamide (DMF) is a primarysolvent for peptide synthesis. Water and free-amines are major contaminants. Dimethyl amine (DMA) can form via the breakdown of DMF in the presence of traces of water. Molecular TrapsTM can be used to remove both traces water and DMA from DMF, thus improving the synthesis.

Other Applications

Molecular TrapsTM can also be used in maintaining "superdry" ethanol (following triazeotopic distillation w/benzene), and in the specific maintenance of anhydrous solvents through daily laboratory usage.
1-Methyl-2- Pyrrolidone (NMP) is a solvent used in many biotech applications. Molecular TrapsTM are very effective in removing both trace water and methylamine from this solvent to improve its purity and performance.

NOTE:   Molecular TrapsTM are not designed to be used in aqueous solutions! Avoid exposure to solvents with high water content as heat may be  produced.


Molecular TrapsTM are non-hazardous as received. Once used, they become contaminated with the chemicals and solvents they are exposed to and then should be treated as contaminated waste. For volatile solvents (e. g. acetonitrile), the exposed traps should be allowed to dry in a hood and then can be disposed of in the trash. Care should be taken to avoid tearing the membrane pouch as molecular sieve dust can be irritating to eyes and mouth.

Sizes and Pricing

We currently offer Molecular TrapsTM in 2, 5 and 10, 25, 50 and 100 gram sizes.
Request quantity pricing.


Suitable for Extended Exposure Suitable for Limited Exposure
Acetone Methylene  Chloride
Acetonitrile Tetrahydrofuran
Acetic Acid (glacial) Toluene
Diethyl ether  
Ethyl Acetate  
Ethyl Alcohol  
Isopropyl Alcohol  
Methyl Alcohol  
Methylethyl Ketone  
1-Methyl-2- Pyrrolidone  

Special vacuum packaging for Molecular Sieves ensure moisture-free storage until opened.