Fiber-Optic System for 77 K Phosphorescence Lifetime Measurements of Polycylic Aromatic Compounds in Shpol'skii Matrices

Abstract

A fiber-optic system is reported for rapid, accurate, and precise 77 K measurements of relatively long phosphorescence lifetimes (τp = 200 ms). The instrument employs stimulated Raman scattering in connection with a pulsed laser source for sample excitation. Phosphorescence decay waveforms are collected at maximum emission wavelengths with a single channel detection system and the aid of a LabVIEW based in-house program acting as a data acquisition instrument, data storage device, and data interpreter. By means of program looping, up to 20 decays are recorded from a frozen sample in less than 5 min. A cryogenic fiber-optic probe directly frozen into the sample matrix removes the random errors associated with the classic sample freezing procedure and provides excellent reproducibility of measurements. The relative standard deviations of τp measured from several polycyclic aromatic compounds varied between 0 and 4.30%. The simplicity of the experimental procedure, the rather large τp differences observed from compounds within the same pollutant class, and the analytical figures of merit provide a solid foundation for pursuing low-temperature phosphorescence, time-resolved low-temperature phosphorescence, and low-temperature multidimensional luminescence analysis.

Photoluminescence spectroscopy of anthrathiophenes and benzonaphthothiophenes in Shpol'skii matrixes

“…A suitable gate time (G) should record the total emission of the phosphor and avoid the collection of background noise. Since this condition is best accomplished with a G approximately equal to 3 phosphorescence lifetimes [43], the appropriate choice of G requires previous knowledge of phosphorescence decays. Table 4 summarizes the 77 K and 4.2 K phosphorescence lifetimes of the studied compounds.…”

Detection of Polycyclic Aromatic Hydrocarbon-DNA Adducts in Placental DNA Samples by Room-Temperature Solid-Matrix Phosphorescence

“…Because of instrument-to-instrument variation and different experimental conditions, a general guideline of AE15 nm was used for the 372 nm band and the 540 nm band for PAH aromatic systems from the literature. An examination from the phosphorescence literature for both roomtemperature and low-temperature phosphorescence spectral properties for PAH gave the following PAH that have excitation and emission bands within the general guideline: fluoranthene, benz[b]fluoranthene, dibenz[a,c]anthracene, and dibenz[a,h]anthracene (Salinas-Castillo et al Hagestuen and Campiglia 1998;Martin and Campiglia 2001).…”

“…Considering an excitation wavelength of 347 nm, the following PAH could emit in the 600-670 nm range: pyrene, dibenz [a,c] Hagestuen and Campiglia 1998;Martin and Campiglia 2001;Hagestuen and Campiglia 1999). With an excitation wavelength of 390 nm, the following PAH could emit in the range of 600-670 nm: benzo[k]fluoranthene, indeno[1,2,3-cd]pyrene, anthracence, benzo[a]pyrene, and benzo[g,h,i]perylene (VoDinh 1984;Hagestuen, Arruda, and Campiglia 2000;Salinas-Castillo et al 2004;Salinas-Castillo et al 2005;Hagestuen and Campiglia 1998;Martin and Campiglia 2001;Hagestuen and Campiglia 1999;Campiglia, Bystol, and Yu 2006).…”

“…With an excitation wavelength of 390 nm, the following PAH could emit in the range of 600-670 nm: benzo[k]fluoranthene, indeno[1,2,3-cd]pyrene, anthracence, benzo[a]pyrene, and benzo[g,h,i]perylene (VoDinh 1984;Hagestuen, Arruda, and Campiglia 2000;Salinas-Castillo et al 2004;Salinas-Castillo et al 2005;Hagestuen and Campiglia 1998;Martin and Campiglia 2001;Hagestuen and Campiglia 1999;Campiglia, Bystol, and Yu 2006). It is clear that there are several possible aromatic ring systems in the placental DNA sample that would be revealed by SMP.…”

Identification, quantitation, and qualification of PVC multifunctional systems with near‐infrared spectroscopy and chemometrics

“…In cases when this first approach is not attainable, a second approach is the utilization of classification methods (1,2,(7)(8)(9)(10). Having generated a set of production samples with known performance characteristics, it becomes possible to determine if an unknown falls within the accepted boundaries of the group.…”