Method Of Field Induced Photoionization Of Molecules Using Low Power Pointer Laser In Laser Assisted Paper Spray Ionization Mass Spectrometry (LAPSI MS)

Technology: Laser assisted paper spray ionization mass spectrometry (LAPSI MS) method;

Industry/Application: Edible Oil Industry, cosmetic industry, Special Metal Industry;

Market: The global mass spectrometry market is projected to reach at a CAGR of 6.25% during the period (2024-29).

The problem statement discussed in the present invention is how to detect saturated & unsaturated hydrocarbons using a laser assisted paper spray ionization mass spectrometry (LAPSI MS) method.
Hence, subject invention addresses the issue efficiently

Present patent describes a laser assisted paper spray ionization mass spectrometry (LAPSI MS) method for detecting saturated and unsaturated hydrocarbons.
A 532nm, ≤10mW laser pointer was shone to a triangularly cut paper along with high voltage, to effect ionization.
The analyte solution was continuously pushed through a fused silica capillary, using a syringe pump, at a preferred infusion rate.
LAPSI MS showed enhanced ionization with high signal intensity of analytes. LAPSI MS works both in positive and negative modes of ionization.
The substrate used to hold the sample includes, a paper, a cloth, a polymer surface (e.g. PVDF) & a cellulose membrane.
A clear enhancement of signal intensity was visualized in the total ion chromatogram for an analyte in presence of the laser.
The field-induced distortion of the potential well can be large in paper spray as the fibers constituting the paper are separated at tens of nanometers apart & consequently the analyte molecules are subjected to very large electric field of the order of 107 Vcm-1

Facilitates enhanced ionization with high signal intensity of analytes, which provides field induced photoionization of molecules;
Said method is used to produce clean mass spectrum with enhanced signal to noise ratio.
The substrate can be modified by nanoparticles-coating on it for in-situ monitoring of photo-catalytic reactions on nanoparticles.
The ionization is used for selective detection of an impurity in a mixture.
The laser used is of another wavelength which causes effective ionization by varying the applied potential.
Monitoring in-situ photo-assisted reactions like, the
Decarboxylation of marcaptobenzoic acid in presence of gold and silver nanoparticles & dehydrogenation reaction of 2,3-dihydro-1H-isoindole. Impurities like mineral oils were detected in commercially available vegetable oil.

Prof. Pradeep T

Dept. of Chemistry

TRL- 4

Experimentally validated in Lab

Technology Transfer