Potential primary measurement tool for the quantification of DNA

Area of Science:

• Analytical Chemistry
• Biochemistry

Background:

• Accurate phosphorus quantification in nucleic acids is crucial for developing certified reference materials (CRMs).
• Traditional methods often require substantial sample mass, limiting analysis of precious or limited-volume samples like nucleotides and deoxyribonucleic acid (DNA).

Purpose of the Study:

• To develop and validate an automated sample introduction system for precise phosphorus measurement in nucleic acids.
• To reduce the required sample mass for phosphorus analysis in nucleotides and DNA using inductively coupled plasma optical emission spectrometry (ICP-OES).

Main Methods:

• Integration of a demountable direct injection high-efficiency nebulizer (d-DIHEN) with ICP-OES.
• Optimization of solution uptake rate and volume for direct injection analysis.
• Implementation of high-performance (HP) methodology for simultaneous internal standardization and drift correction.

Main Results:

• The d-DIHEN system reduced solution uptake rate and volume, significantly decreasing the required DNA sample mass (from 300 to 72 µg for 3 µg g⁻¹ P).
• Direct injection improved phosphorus (P (I) 213.617 nm) sensitivity by an average factor of 4.
• The methodology achieved low relative expanded uncertainties (0.1–0.4%) for phosphorus mass fractions in various DNA samples.
• Quantification of DNA mass at P mass fractions as low as 0.5 µg g⁻¹ was achieved, requiring only 12 µg of DNA with < 0.4% uncertainty.

Conclusions:

• The automated d-DIHEN with HP-ICP-OES provides a highly sensitive and efficient method for phosphorus determination in nucleic acids.
• This approach significantly reduces sample mass requirements, facilitating the development and certification of nucleic acid CRMs, especially for limited-volume samples.