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Ultramer® RNA Oligonucleotides

Single-stranded RNA oligos up to 120 bases, desalted and delivered dry in tubes.

Ultramer RNA Oligonucleotides are manufactured using proprietary synthesis methods that deliver high quality, long RNA oligos. Each oligo is quality controlled by electrospray ionization–mass spectrometry. Turnaround time is 6–8 business days.

  • Increase specificity in your experiments using longer RNA oligos (60–120 bases)
  • Experience greater flexibility for RNA-related applications, including CRISPR, RNA therapeutics development, and RNA controls and templates
  • Receive guaranteed quantities of 4 nmol, 20 nmol, or 80 nmol
  • Verify the high quality of your oligos with free quality control documentation


Ultramer RNA Oligos

Formulated to guaranteed quantities of 4, 20, or 80 nmol. Shipped dry, in tubes.


IDT has developed proprietary synthesis methods to deliver high quality, long RNA oligos up to 120 bases. With Ultramer RNA Oligonucleotides, you can achieve increased specificity and improved performance in a variety of RNA-related applications. These include, but are not limited to:

  • Single -guide RNAs (sgRNAs) for CRISPR
  • Long RNAs for RNA therapeutics development
  • RNA controls for PCR and qPCR

Upon placing an order, you will receive your Ultramer RNA Oligos in 6–8 business days, dry and in tubes. Ultramer RNA Oligos are desalted to remove small molecular impurities and formulated to 4 nmol, 20 nmol, or 80 nmol. Every Ultramer RNA Oligo you receive will be deprotected and desalted to remove small molecule impurities. In addition, your oligos will be sequence-verified via proprietary ESI-mass spectrometry methods, and quantitated twice by UV spectrophotometry to provide accurate yield measurements.

Using the RNA Oligo Entry tool

  • To enter individual RNA bases, insert "r" before the base (rA, rU, rC, rG)
  • To enter individual 2′-O-Methyl RNA bases, insert "m" before the base (mA, mU, rC, rG)
  • To quickly convert an entire oligo to RNA, enter your sequence as DNA using A, T, C, G and then click “Convert to “RNA”. All bases in your sequence will be converted to RNA (rA, rU, rC, rG)

IDT employs proprietary equipment that permits rapid, high quality synthesis of nucleic acids. However, this platform can be modified to a lower throughput mode that uses an "extra rich" synthesis cycle. Along with this refined synthesis cycle, Ultramer RNA Oligos use a unique solid support that is specifically optimized for synthesis of low-yield, high-quality RNA oligos up to 120 bases in length. Overall, these improvements to our already established manufacturing methods allow you to acquire longer, purer oligos for your research. Figure 1 illustrates the exceptional quality of Ultramer RNA Oligos.

Figure 1. The general relationship between percentage of full-length product, coupling efficiency, and oligo length. Coupling efficiency becomes increasingly important with increased oligo length. For long oligos, small changes in coupling efficiency have dramatic effects on full-length yield. The graph depicts the difference in full-length product for coupling efficiencies of 99.0–99.3% (dark blue) and 98.0–98.5% (light blue).

Performing QC on long oligonucleotides is complex, even with a method as precise as ESI-MS. Truncated byproducts of synthesis will obscure the mass spectra, making it difficult to deconvolute and identify the desired species. Our proprietary mass spectrometry methods enable us to confidently QC your Ultramer RNA Oligos up to 120 bases (Figure 2). Importantly, we provide ESI-MS quality documentation for every oligo we synthesize.

Figure 2A. QC data demonstrates high purity of a 90mer Ultramer RNA Oligo. The measured molecular weight of the oligo matches its expected molecular weight, which is determined by the specific oligo sequence. Data generated from ESI-MS instruments at IDT.

Figure 2B. QC data demonstrates high purity of a 120mer Ultramer RNA Oligo. The measured molecular weight of the oligo is within 0.01% of its expected molecular weight, which is determined by the specific oligo sequence. Data generated from ESI-MS instruments at IDT.

Frequently asked questions

OligoAnalyzer® tool

Identify oligonucleotide properties, including melting temperature, hairpins, dimers and mismatches

UNAFold tool

Perform secondary structure analysis

Dilution Calculator

Find the volume needed to dilute your oligo stock to a lower concentration

Resuspension Calculator

Find the volume needed to resuspend a dry oligo to a desired concentration

To provide you with an exceptional experience when using our custom oligos, we offer a range of custom purification, formulation, and quality control services. To learn more about available services for Ultramer RNA oligos, click here.

Large-scale synthesis

Custom RNA oligos can be ordered in bulk with the same high purity, competitive pricing, and fast turnaround times you expect from IDT. For further information about our large-scale synthesis capabilites, click here.


If you require oligos that are approved for use in molecular diagnostic applications, or if you are interested in our third-party manufacturing services, please click here.