HPLC-DAD (UV Absorption Spectroscopy)

Liquid chromatography equipped with photodiode-array detection (HPLC-DAD) allows for the detection of components with unique UV-Vis absorption characteristics (typically organic compounds with aromatic structures).

The basic principle of photodiode-array detectors (DAD) involves passing a beam of UV-Vis light through a HPLC column effluent, which contains separated compounds. The light is absorbed by the sample, and the amount of light absorbed at different wavelengths is recorded by the diode array detector. The recorded absorbance spectra are then used to identify and quantify the separated compounds based on their unique UV-Vis spectra. The advantages of DAD include the ability to collect spectra over a broad range of wavelengths, which allows for more accurate identification and quantification of complex mixtures of compounds.

HPLC-FLD (Fluorescence spectroscopy)

Liquid chromatography equipped with fluorescence detection (HPLC-FLD) allows for the detection of components that emit fluorescence signals.

The detection mechanism of HPLC-FLD is based on the ability of certain compounds to fluoresce, where the light wave they emit is at a longer wavelength than the excitation wavelength. The excitation wavelength is chosen based on the specific compound being analyzed, as different compounds have different optimal excitation wavelengths. Because each compound has their own unique excitation and emission wavelength, FLD detection is generally excellent in sensitivity and selectivity, making it an excellent option for detecting and quantifying traces of fluorescent compounds in complex mixtures as well as in materials and components in a wide variety of consumer products and electronics.

LC-MS / LC-QTOF (Mass Spectroscopy)

Liquid chromatography equipped with mass spectrometry (LC-MS) detects molecules by ionizing and separating compounds based on their mass-to-charge ratio. The resulting mass spectra provide information about the identity and quantity of each individual components in the sample.

Quadrupole time-of-flight (QTOF) mass spectrometry is a type of high-resolution mass spectrometry that can detect trace level down to sub 10 ppb with high level of accuracy. It can detect a wide range of molecules, ranging from small molecules, such as phenol and formaldehyde, as well as larger molecules, such as polymers. The time-of-flight mass spectrometer measures the time taken for the ions to travel to the detector, which is proportional to their mass-to-charge ratio. The resulting mass spectra provide highly accurate and precise information about the mass and abundance of the individual components in the sample.

The high sensitivity and selectivity to organic molecules makes LC-QTOF an effective tool for detecting traces of organic impurities and contaminants in a variety of materials and/or components in a wide variety of consumer products and electronics.