--- title: Oligo Deprotection Guide (DNA + RNA) description: deprotection --- [Skip to content](https://support.sierrabio.com/oligo-deprotection-guide-dna-rna#main-content) English Show submenu for translations ![](https://support.sierrabio.com/hs-fs/hubfs/JPG%20file%20-02.jpg?width=2000&height=1125&name=JPG%20file%20-02.jpg) Open main navigation Close main navigation - English Show submenu for translations - [Contact us](mailto:support@sierrabio.com) [Contact us](mailto:support@sierrabio.com) How can we help you? - There are no suggestions because the search field is empty. 1. [Sierra Biosystems Support Center](https://support.sierrabio.com/?hsLang=en) 2. [Oligonucleotide Chemistry & Methods](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en) 3. [Post-Synthesis Processing](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en#post-synthesis-processing) January 25, 2026 # Oligo Deprotection Guide (DNA + RNA) ## How to Choose Conditions Without Destroying Your Product ### If your oligo is **unmodified DNA** - Use a **standard ammonium hydroxide–based** deprotection workflow unless you have a reason not to. ### If you need **fast turnaround / high throughput** - Consider **UltraFAST / AMA-based deprotection** (fast, common in high-volume environments), but confirm **your monomer protecting groups are compatible** (especially cytosine protection). ### If your oligo includes **base‑labile groups, sensitive dyes, or special modifiers** - Use a **mild / UltraMild** approach (often carbonate-in-methanol or other mild systems), and follow the modifier manufacturer’s conditions. ### If your oligo is **RNA or chimera (DNA/RNA)** - RNA deprotection is **two-stage**: (1) cleavage/phosphate/base deprotection while **keeping 2’ protection**, then (2) **2’‑deprotection** to yield functional RNA. --- #### 1) What “deprotection” actually includes Oligo deprotection has three linked parts: 1. **Cleavage**: release oligo from solid support 2. **Phosphate deprotection**: remove cyanoethyl groups from backbone 3. **Base/modifier deprotection**: remove nucleobase protecting groups and any modifier protecting groups You don’t “pick a deprotection method” in the abstract — you pick a method that is compatible with **every component** in the sequence (bases + dyes + linkers + special monomers). --- #### 2) Inventory what’s in the oligo Before selecting conditions, list: - DNA vs RNA (or chimera) - Base protections used (especially **dC** and **dG**) - Any dyes / quenchers / hydrophobic labels - Any base‑labile or ester‑containing groups (examples include certain linkers or specialty bases) - Whether you need to retain **DMT‑ON** for purification This is the fastest way to prevent the two classic failure modes: - **incomplete deprotection** (oligo “looks right-ish” but performs poorly) - **damage to the expensive part** (dye/modifier gets cooked) The guide is explicit that sensitive components often require **different** deprotection schemes than “regular” oligos. --- #### 3) DNA deprotection options (how to choose) ### A) Standard deprotection (baseline) Best when: - Unmodified DNA - No base-labile dyes/modifiers Key success factor: - **Deprotect to completion** (partial deprotection creates messy profiles and poor performance). --- ### B) UltraFAST (AMA) deprotection (speed + throughput) **AMA = 1:1 ammonium hydroxide : methylamine (v/v)**. Why people use it: - Deprotection can be completed in **minutes**, enabling same‑day release in high-volume settings. Critical compatibility note: - UltraFAST **requires acetyl-protected dC (Ac‑dC)** to avoid **base modification** that can occur when methylamine reacts with Bz‑dC. Practical framing: - If your shop wants **fast + scalable**, AMA is the default “fast lane,” but **only** when the chemistry is compatible. --- ### C) Mild deprotection for ester‑sensitive / amine‑sensitive oligos If you have components that would react badly with amines, the guide describes **sodium hydroxide in aqueous alcoholic solvent** as a mild alternative. Example use case from the guide: - Situations where **amine-containing reagents** would create undesired chemistry (e.g., ester → amide issues). Note: - This approach typically requires a **desalting** step; you can’t always just evaporate and go. --- ### D) UltraMild deprotection (protect the fragile stuff) UltraMild workflows are designed for: - base-labile bases / damage-repair analogs - sensitive modifiers and dyes that don’t tolerate NH₄OH or AMA A common UltraMild strategy uses: - **UltraMild monomers** (e.g., Pac‑dA, Ac‑dC, iPr‑Pac‑dG) - **potassium carbonate in methanol** for base deprotection Important nuance: - Deprotection time can depend on capping chemistry (some capping choices create byproducts that require longer removal). --- #### 4) RNA deprotection (what’s different and why it matters) RNA (and chimeras) are unique because the **2’ protecting group must stay on** during early steps. You only remove it after: - cleavage - cyanoethyl removal - base deprotection ### A) Base deprotection for RNA The guide highlights: - **AMA at elevated temperature** as a unified approach that works well for common RNA protection strategies (TOM and TBDMS), **with Ac‑protected C monomers required**. It also describes an **UltraMild RNA** option: - NH₄OH/EtOH (3:1) at room temperature (used when oligo contains base-labile groups). ### B) 2’‑deprotection (to get functional RNA) Commonly used approaches include: - **TEA·3HF-based cocktails** (triethylamine trihydrofluoride), which have become widely used and are compatible with precipitation and cartridge workflows. Practical handling warnings from the guide: - Maintain **sterile / RNase‑free** conditions after base deprotection. - Avoid glass for certain fluoride-based steps; use appropriate plasticware as directed. --- #### 5) Dye-containing / heavily modified oligos (how to not ruin labels) General principle: - If a dye/modifier is present, it may dictate the deprotection method. The guide explicitly calls out dyes like TAMRA/HEX as examples that can force a different procedure than standard. Practical “safe” posture: - When in doubt, pick the **mildest** conditions that still achieve **complete** deprotection, and verify dye stability. A notable approach described: - For some TAMRA-containing oligos, alternative deprotection using **t‑butylamine-based systems** is described as an option. --- #### 6) Scale / parallel processing options: Gas-phase and on-column deprotection When you have many oligos to process, the guide highlights methods that reduce manual labor and can be parallelized. ### On-column deprotection in organic solvent (practical, scalable) **On-column deprotection in organic solvents** as a practical route that captures some convenience of gas-phase methods while avoiding specialized gas handling setups. ([Glen Research](https://www.glenresearch.com/reports/gr22-27)) Typical concept (high-level): - Remove cyanoethyl groups - Then apply an organic-solvent deprotection reagent on-column - Then elute and proceed to downstream cleanup (For any on-column workflow, always verify compatibility with your support chemistry + modifiers.) --- #### 7) Troubleshooting quick hits (what to check first) ### If you see odd HPLC peaks / “extra” components - Incomplete deprotection can shift retention and generate confusing peak patterns; the guide shows how partial vs complete deprotection changes profiles. ### If your RNA yield/purtivity is poor - Double-check that: - base deprotection completed - 2’ deprotection completed - RNase-free handling was maintained ### Assume chemistry damage first: - move to UltraMild conditions - confirm the modifier’s required pretreatments and stability windows - [Pre-Installation & Installation](https://support.sierrabio.com/pre-installation-installation?hsLang=en#main-content) - [Pre-Installation Requirements](https://support.sierrabio.com/pre-installation-installation?hsLang=en#pre-installation-requirements) - [Site & Lab Preparation](https://support.sierrabio.com/pre-installation-installation?hsLang=en#site-lab-preparation) - [Installation & Initial Setup](https://support.sierrabio.com/pre-installation-installation?hsLang=en#installation-initial-setup) - [Troubleshooting & Errors](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#main-content) - [Software Errors & Communication Issues](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#software-errors-communication-issues) - [Chemistry and Protocol-Related Issues](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#chemistry-and-protocol-related-issues) - [K&A - Preventative Maintenance & Quick Fixes](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#ka-preventative-maintenance-quick-fixes) - [Shasta - Preventative Maintenance & Quick Fixes](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#shasta-preventative-maintenance-quick-fixes) - [Shasta - Hardware Issues](https://support.sierrabio.com/troubleshooting-errors?hsLang=en#shasta-hardware-issues) - [Training Videos and Guides](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#main-content) - [Shasta Software](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#shasta-software) - [K&A Next Gen Software](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#ka-next-gen-software) - [K&A Legacy Software](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#ka-legacy-software) - [K&A - Troubleshooting Videos](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#ka-troubleshooting-videos) - [Shasta - Troubleshooting Videos](https://support.sierrabio.com/training-videos-and-guides?hsLang=en#shasta-troubleshooting-videos) - [Software Updates & Release Notes](https://support.sierrabio.com/software-updates-release-notes?hsLang=en#main-content) - [Release Notes](https://support.sierrabio.com/software-updates-release-notes?hsLang=en#release-notes) - [Downloads](https://support.sierrabio.com/software-updates-release-notes?hsLang=en#downloads) - [Update Instructions](https://support.sierrabio.com/software-updates-release-notes?hsLang=en#update-instructions) - [Product Documentation & Policies](https://support.sierrabio.com/product-documentation-policies?hsLang=en#main-content) - [Technical Documentation](https://support.sierrabio.com/product-documentation-policies?hsLang=en#technical-documentation) - [Specifications](https://support.sierrabio.com/product-documentation-policies?hsLang=en#specifications) - [Warranty & Service](https://support.sierrabio.com/product-documentation-policies?hsLang=en#warranty-service) - [Oligonucleotide Chemistry & Methods](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en#main-content) - [Synthesis & Strategy](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en#synthesis-strategy) - [Post-Synthesis Processing](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en#post-synthesis-processing) - [Quantitation & QC](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en#quantitation-qc) - [Special Topics](https://support.sierrabio.com/oligonucleotide-chemistry-methods?hsLang=en#special-topics) - [Support & Contact](https://support.sierrabio.com/support-contact?hsLang=en) - [Uncategorized](https://support.sierrabio.com/uncategorized?hsLang=en) [![](https://support.sierrabio.com/hs-fs/hubfs/JPG%20file%20-02.jpg?width=2000&height=1125&name=JPG%20file%20-02.jpg)](http://sierrabio.com) [mailto:Support@sierrabio.com](mailto:Support@sierrabio.com) Copyright © 2025, Sierra BioSystems