What is OD260/280 Concentration?

OD260/280 concentration calculator — Calculate nucleic acid concentration (µg/mL, ng/µL) from 260 nm absorbance, dilution factor, and nucleic-acid-specific extinction factor (NanoDrop, etc.). Also evaluates protein contamination via A260/A280 ratio.

When should I use OD260/280 Concentration?

(1) Measure genomic DNA / plasmid prep concentration (e.g., NanoDrop 1 µL) (2) RNA prep concentration + purity check (A260/A280 ≥ 1.8, A260/A230 ≥ 2.0 recommended) (3) Verify ssDNA oligo / primer concentration (4) Compute input mass for PCR/cloning (ng/µL → ligation amounts)

Can you show me an example of OD260/280 Concentration?

Example 1) Plasmid prep (dsDNA), NanoDrop → A260 = 0.45, A280 = 0.24, dilution = 1, path = 1 cm → Conc = 0.45 × 50 × 1 = 22.5 µg/mL = 22.5 ng/µL → A260/A280 = 1.88 → good Example 2) Total RNA TRIzol extraction → A260 = 1.20, A280 = 0.60, dilution = 100 → Conc = 1.20 × 40 × 100 = 4,800 µg/mL = 4.8 µg/µL → A260/A280 = 2.0 → good

OD260/280 Concentration

흡광도 값으로 DNA/RNA 농도 산출

Conc = OD260 × dilution × factor

SAMPLE TYPE

Extinction factor: 50 µg/mL per OD | Ideal 260/280: 1.8–2

A₂₆₀ *

A₂₈₀

A₂₃₀

Dilution

도구 가이드

정의

OD260/280 농도 산출기 — UV-Vis spectrophotometer(NanoDrop 등)로 측정한 260 nm 흡광도와 희석배수, 핵산 종류별 extinction factor를 이용해 nucleic acid 농도(µg/mL, ng/µL)를 계산합니다. A260/A280 비율로 단백질 contamination도 평가합니다.

목적

(1) Genomic DNA / plasmid prep 농도 측정 (예: NanoDrop 1 µL) (2) RNA prep 농도 + 순도 평가 (A260/A280 ≥ 1.8, A260/A230 ≥ 2.0 권장) (3) ssDNA oligo·primer 농도 검증 (4) PCR/cloning input mass 환산 (ng/µL → ligation 양 결정)

사용법

① Sample type 선택 (dsDNA: 50 µg/mL per OD / ssDNA: 33 / RNA: 40 / ssOligo: 33) ② A260 측정값 입력 ③ Dilution factor (NanoDrop은 보통 1, cuvette은 100배 희석 시 100) ④ Path length (NanoDrop 1 mm = 0.1 cm, cuvette 1 cm) ⑤ A280 입력 시 A260/A280 ratio 자동 표시 출력: Concentration (ng/µL), A260/A280 ratio + purity 평가 코멘트.

예시

예 1) Plasmid prep (dsDNA) NanoDrop → A260 = 0.45, A280 = 0.24, dilution = 1, path = 1 cm → Conc = 0.45 × 50 × 1 = 22.5 µg/mL = 22.5 ng/µL → A260/A280 = 1.88 → 양호 예 2) Total RNA TRIzol extraction → A260 = 1.20, A280 = 0.60, dilution = 100 → Conc = 1.20 × 40 × 100 = 4,800 µg/mL = 4.8 µg/µL → A260/A280 = 2.0 → 양호