Fluorescent Modified Oligos

Our specialty modification department is dedicated to the synthesis of modified oligos including optimizing protocols, exploring new chemistries, consulting with customers, and ensuring product quality.

Capabilities
Sigma^® can attach fluorescent dyes to oligos at the 5'-end, 3'-end and even internal positions.  Our product offering includes common dye modifiers such as 6-FAM, HEX, and TET, as well as exotic modifications.  We are a licensed supplier of modifications from Molecular Probes, Inc., Biosearch Technologies, and PHRI, City of New York. 

In addition to standard fluorescent modifications, we have the capabilities to provide dual-labeled probes including Molecular Beacons. 

Maximal Absorbance and Emission for Common Fluorophores

Synthesis Scales
Most modifications are available at the 0.05, 0.2, and 1.0 µmole scale.  Please call for large scale projects.

Purification
Desalt or cartridge (RP1) purification is acceptable for most common phosphoramidite modifiers.  However, additional purification such as HPLC is strongly recommended for modifiers that require NHS-ester chemistry to conjugate a dye through an amine linker such as Molecular Probes dyes.

Guaranteed Yield
Due to the chemistry of many modifications, yield will be approximately 40 - 60 % less than a standard oligo.  Please see our yield chart for details.

Guaranteed Quality
Every oligo synthesized is strictly controlled for quality by using either MALDI-TOF mass spectrometry or polyacrylamide gel electrophoresis (PAGE) analysis.  Final yields are determined using UV absorbance at OD₂₆₀.  In addition, we perform specialized QC methods tailored to specific modifications, such as OD ratio measurement where appropriate. 

You will receive a Quality Assurance Certificate that includes quantitated yield, melting temperature, MW and µg/OD with every oligo.  You will also receive an additional label for use in your records or on an additional vial. 

Delivery
Expected shipment time for common dye modifiers is 3 - 5 working days.  More exotic modifications are usually completed within 5 - 7 working days. 

Pricing
Modification pricing is per modification and does not include base charges.  Contact your Account Representative for pricing on multiple modifications or to request a large volume quote.

For additional information, please send your request to ginformation@sial.com or call us at 800-234-5DNA (5362).