introduction: amajor problem in the treatment of cancer is the lack of an appropriate method for the early diagnosis of the disease. the chemical reaction within an organ may be reflected in the form of proteomic patterns in the serum, sputum, or urine. laser mass spectrometry is a valuable tool for extracting the proteomic patterns from biological samples. a major challenge in extracting such ...

Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometers are simple and robust mass spectrometers used for analysis of biologically relevant molecules in diverse fields including pathogen identification, imaging mass spectrometry, and natural products chemistry. Despite high nominal resolution and accuracy, we have observed significant variability where 30-50% o...

A tunable Cr:LiSAF laser-pumped optical parametric oscillator was used for mid-infrared matrix-assisted laser desorption/ionization (MALDI) mass spectrometry experiments. The mass spectra of substance P, bovine insulin and pd(T)10 in the 2.88-2.96 microns range showed excellent single shot signal quality (signal-to-noise-ratio, resolution) but poor shot-to-shot reproducibility. The reproducibil...

Background: The theory of selective photo-thermolysis led to the development of a variety of different laser systems which range from the shorter spectrum of 694nm ruby laser to the middle with the 755nm alexandrite and 810nm diode lasers to the long end with the 1064nm (Nd:YAG) laser. Objective: A systematic review on the clinical trials with use of various laser sources for hair removal...

A series of four spiropyrans bearing different substituents on the indolic nitrogen were synthesized and their capability of binding mono and bivalent transition metal cations in solution was assessed via UV-visible absorption spectroscopy. All the compounds responded selectively to the presence of Cu(ii) ions producing intense absorption bands in the visible region of their spectra. Bidimensio...

A time-of-flight mass spectrometer (TOF-MS) developed in our laboratory at Isfahan University of Technology is described here. The TOF-MS instrument uses laser as the ionization source which provides an opportunity to investigate the ions formed in laser ablation or desorption. The TOF-MS has an ionization chamber containing an accelerator and an ion lens to focus the ions into a one meter line...

The mass spectral detection of low vapor pressure, inorganic-based explosive signatures including ammonium nitrate, chlorate, perchlorate, sugar, and the constituents contained within black powder are reported using laser electrospray mass spectrometry. The ambient pressure mass spectrometry technique combining nonresonant, femtosecond laser vaporization with electrospray postionization reveale...

Introduction: Amajor problem in the treatment of cancer is the lack of an appropriate method for the early diagnosis of the disease. The chemical reaction within an organ may be reflected in the form of proteomic patterns in the serum, sputum, or urine. Laser mass spectrometry is a valuable tool for extracting the proteomic patterns from biological samples. A major challenge in extracting such ...

A tandem time-of-flight mass spectrometer for the study of photodissociation of biopolymer ions generated by matrix-assisted laser desorption ionization was designed and constructed. A reflectron with linear and quadratic (LPQ) potential components was used. Characteristics of the LPQ reflectron and its utility as the second stage analyzer of the tandem mass spectrometer were investigated. Perf...

In this research, tunability of a commercial diode laser has extended to about more than ± 11 nm using a V-shaped external-cavity fabricated around the laser. Although under normal condition it can be tuned up to about ± 4 nm just by changing its temperature and injection current. Such modified diode laser has then used in a difference-frequency generation (DFG) experimental setup as pump sourc...