Part 1: Most Common HPLC Detectors

  • Diode array detector (PDA): Limit of detection < 2 × 10⁻⁵ g/mL
  • Ultraviolet/visible light absorption (UV): Limit of detection 10⁻⁹ g/mL
  • Fluorescence: Limit of detection 10⁻¹² g/mL
  • Refractive index detector (RI): Limit of detection 10⁻⁶ g/mL
  • Evaporative light scattering: Limit of detection 10⁻⁹ g/mL
  • Amperometric detector: Limit of detection 10⁻¹⁰ g/mL
  • Mass spectrometry detector (MS): Limit of detection 10⁻⁹–10⁻¹² g/mL

Part 2: All Types of Detectors With Sensitivity

DetectorSensitivityCell Volume (µl)Remarks
Ultraviolet (visible) spectroscopy (AUFS)1 ng ml⁻¹, 1 × 10⁻³4.5–20Common detector; selection of wavelength improves the accuracy of quantitative analysis, wavelength scanning or photodiode array permits qualitative analysis. W-lamp or complex lamp is suitable for visible region detection.
Fluorescence spectroscopy10 pg ml⁻¹, 1 × 10⁻⁴ FS7–60Sensitive for fluorescent compounds
Refractive Index10 ng ml⁻¹, 1.6 × 10⁻⁷ RIU5–14All purpose; temperature control for high sensitive detection, usually used for preparative LC or size exclusion LC, eluent must be isocratic
Polarimeter20 µg ml⁻¹Specific for optical isomers
Infrared spectroscopy10 ng ml⁻¹Suitable for carbonyl compounds; NaCl, CaF₂ and sapphire cells are available
Conductivity10 ng ml⁻¹1.5Detection limit 0.001 µmho is equivalent to 0.01 ppm NaCl, suitable for ion detection
Polarography1 ng ml⁻¹, 2 × 10⁻⁸ µA10Suitable for ions, fatty acids, saccharides
Coulometry50 pg s⁻¹, 5 × 10⁻⁸ A
Amperometry50 ng ml⁻¹, 10 pASuitable for catecholamines, phenols
Pulsed amperometry50 ng ml⁻¹, 10 pASuitable for saccharides
Flame ionization1 ng ml⁻¹, 10 pAOrganic compounds containing carbon-hydrogen bonds
Electron capture100 pg ml⁻¹Mostly suitable for halogenated compounds
Mass spectrometer10 pg ml⁻¹All purpose; qualitative and quantitative detector
Inductive coupled plasma20 ng ml⁻¹Element selective
Atomic absorption20 ng ml⁻¹Organometallic compounds
Reaction heatng s⁻¹9All purpose
Radioactivity (14C: 2nCi, 3H: 5nCi)50–700Metabolite analysis

Table 3: Comparison of Selected Mass Spectrometry Instruments

Mass AnalyserSensitivity in Full Spectra AcquisitionSelectivityMass AccuracyLinear Dynamic Range
Quadrupole++++++
Ion Trap (MS¹)++++++++
Sector+++++++
High-Resolution Time-of-Flight (HRTOF)+++++++++
High-Speed Time-of-Flight (HSTOF)++++++++++
Triple Quadrupole (QqQ)+++++++++
Ion Trap (MS²)+++++++++++
Quadrupole/Time-of-Flight (QTOF)+++++++++

Reference: HPLC: A Practical Guide

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