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Purity of dNTPs is an important parameter for assessing their suitability for PCR reactions run by clinical/diagnostic laboratories or molecular biologists. Even minute amounts of impurities may interfere with PCR and are therefore commonly termed "PCR inhibitors".
RP-HPLC purity data only include UV-absorbing impurities, such as nucleosides or nucleotides. Inorganic species however, do not absorb in the UV and thus will escape HPLC detection.
Hence, in parallel to HPLC quality control, LAROVA uses Analytical Anion Chromatography (AAC), GC/FID and ICP-MS to detect inorganic impurities such as phosphate, pyrophosphate and various metal ions.
The table below shows some examples of common inorganic impurities present in dNTP preparations, their concentration reported to be critical in PCR and their maximum tolerated concentration in LAROVA's dNTPs.
For phosphate and pyrophosphate, no or no consistent data for critical concentrations are published. Therefore, we systematically investigated the interference of increasing concentrations of phosphate or pyrophosphate with 18 kb PCR runs (see figure 1 below).
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Figure 1: Interference of increasing concentrations of phosphate (left) and pyrophosphate (above) with 18 kb PCR runs. Phosphate will inhibit PCR at a concentration of 7 mM. Pyrophosphate leads to a significant decrease of PCR product yield at a concentration of 0.5 mM, and will inhibit PCR at 0.7 mM.
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Find more details on dNTP quality parameters and analysis in our dNTP Guide:
 LAROVA dNTP Guide (PDF, 1.4 MB)
View our complete dNTP specifications here:
LAROVA dNTP specifications (PDF, 59 kB)
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LAROVA GmbH