The Effects of Salts on the Room-Temperature Fluorescence and Room-Temperature Phosphorescence of Tetrols on Filter Paper and Filter Paper with Silicone

Abstract

Several salts were investigated to enhance the room-temperature solid-matrix phosphorescence of the four stereoisomeric tetrols on filter paper. Thallium acetate was found to enhance the phosphorescence to the greatest extent, but it was necessary to prepare the thallium acetate in an acetic acid solution to achieve the maximum phosphorescence from the solid matrix. Also, thallium acetate essentially quenched the solid-matrix fluorescence of the tetrols. Without thallium acetate adsorbed on filter paper, strong room-temperature fluorescence signals were observed from the tetrols adsorbed on filter paper. With a new solid matrix, filter paper which contained silicone, no heavy-atom was needed to obtain strong phosphorescence from the adsorbed tetrols. In fact, the room-temperature fluorescence from the tetrols adsorbed on this type of filter paper was very strong. The room-temperature fluorescence gave a limit of detection in the sub-picogram range for one of the tetrols with the silicone treated filter paper.     

Analytical and mechanistic aspects of the room-temperature fluorescence and phosphorescence of benzo(f)quinoline adsorbed on silica gel chromatoplates with humidified gases

The solid-matrix room-temperature fluorescence and room-temperature phosphorescence properties of benzo(f)quinoline adsorbed on silica gel chromatoplates were investigated over a wide range of humidities in N(2), air and O(2). Both neutral and acidic conditions were used and even at the highest relative humidity used, 93% relative humidity, the room-temperature fluorescence and phosphorescence intensities from benzo(f)quinoline were not totally quenched. However, in all experiments, the room-temperature phosphorescence was much more sensitive to humidity quenching than the room-temperature fluorescence. The results gave rather detailed information on quenching of the room-temperature fluorescence and phosphorescence in the different gases at a variety of humidities. It was possible to calculate the contribution to the percent decrease in luminescence due to moisture or a quenching gas. Thus, a more detailed assessment could be made about the quenching of moisture and individual quenching gases on the solid-matrix fluorescence and phosphorescence.     

Comparison of the Solution Luminescence Properties and Solid-Matrix Luminescence Properties of 2-Amino-1-Methyl-6-Phenylimidazo[4,5-B]Pyridine

Abstract

The solution fluorescence properties of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were compared with the solid-matrix luminescence properties of PhIP. The fluorescence properties were obtained in ethanol and several binary solutions of ethanol:water. An ethanol solution of PhIP gave a very strong fluorescence signal and the ethanol:water solutions only showed a small increase in the fluorescence signal. Acidic solutions of PhIP in ethanol:water (7:3) showed a major decrease in fluorescence intensity with at HCl of 10^?4 M and greater, but NaOH solutions of PhIP did not affect the fluorescence intensity to any great extent. Both acidic and basic solutions gave fluorescence emission spectra that were shifted to longer wavelengths. Solid-matrix room-temperature fluorescence (SMRTF) and solid-matrix room-temperature phosphorescence (SMRTP) were readily obtained on filter paper. SMRTP showed some distinct advantages over SMRTF and gave a limit of detection of 0.2 ng on filter paper. Several aspects of both solution luminescence and solid-matrix luminescence of PhIP are discussed.     

COMPARISON OF THE SOLID-MATRIX LUMINESCENCE PROPERTIES OF BENZO(a)PYRENE-DNA ADDUCTS ON α-CYCLODEXTRIN/NaCl and TREHALOSE/NaCl MATRICES

Abstract— The solid-matrix luminescence properties of (±)- trans -7,8-dihydroxy-anti-9,10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene-DNA ([±]-anti-BPDE-DNA) adducts were compared on α-cyclo-dextrin (CD)/NaCl and trehalose/NaCl solid matrices. Both the optimum composition for the solid matrices and the best solvent system were obtained experimentally for acquiring the maximum room-temperature fluorescence (RTF) and room-temperature phosphorescence (RTP) signals for the (±)- anti -BPDE-DNA. Most of the solid-matrix RTF and RTP data were obtained at 296 K and 93 K for (±)-anti-BPDE-DNA adducts adsorbed on 1%α-CD/NaCl and 80% trehalose/NaCl. The RTF signals were strong for (±)-BPDE-DNA adducts on both solid matrices, but RTP was only obtained on the trehalose/NaCl solid matrices with the 80% trehalose yielding the strongest RTP signal for (±)-anti-BPDE-DNA. The fluorescence lifetime data for (±)-anti-BPDE-DNA gave two components on 1 %α-CD/NaCl. For 80% trehalose/NaCl, three components were revealed, but two components were obtained with 80% trehalose/NaCl after ether extraction of the solid matrix. The third component was ascribed to the formation of the tetrols from (±)- anti -BPDE-DNA adducts during the drying step in the sample preparation of 80% trehalose/NaCl. The results give the first reported data on the solid-matrix luminescence of the (±)- anti -BPDE-DNA adducts. These results should be of considerable interest not only from an analytical viewpoint but as a new means of studying the luminescence characteristics of the adducts.     

COMPARISON OF THE SOLID-MATRIX LUMINESCENCE PROPERTIES and PHOTOPHYSICAL PARAMETERS OF TWO PRODUCTS FROM BENZO(a)PYRENE-DNA ADDUCTS

Abstract The solid-matrix luminescence properties and several calculated photophysical parameters of two important products from the benzo(a)pyrene-DNA adducts were compared. The products were benzo(a)pyrene-r-7,t-8,9,c-10-tetrahydrotetrol (I-1) and 7R,8S,9S-trihydroxy-10R-(A^p-deoxyguanosyl-3'-phosphate)-7,8,9,1O-tetrahydroben-zo(a)pyrene (BPDE-dG). The solid-matrix luminescence data were obtained for 1–1and BPDE-dG adsorbed on two different solid matrices, namely, 1% a-cyclodextrin (CD)/NaCl and 25% trehalose/NaCl and at two different temperatures (93 K and 296 K). The 25% trehalose/NaCl gave higher fluorescence and phosphorescence quantum yields from both 1–1and BPDE-dG in contrast to the 1%α-CD/NaCl matrix. The BPDE-dG showed lower fluorescence quantum yields on the solid matrices compared to 1–1. The lower fluorescence quantum yields for BPDE-dG were attributed to a photoinduced electron transfer mechanism. In contrast to the room-temperature solution fluorescence of BPDE-dG, BPDE-dG gave rather high fluorescence quantum yields at room temperature when adsorbed on the two solid matrices. From solid-matrix luminescence quantum yields and solid-matrix luminescence lifetimes, many photophysical parameters were calculated and compared. Several differences among the rate constants were noted with the two solid matrices for BPDE-dG and 1–1. For example, BPDE-dG showed internal conversion at 296 K with 25% trehalose/NaCl, but no internal conversion was observed at 93 K with this solid matrix. Also, for BPDE-dG the phosphorescence rate constants at 296 K and 93 K. were very small with 25% trehalose/NaCl, but the intersystem crossing rate constants from the triplet state to the ground state were very large. The results from this work show how solid-matrix luminescence can be employed to obtain unique luminescence information from the 1–1and BPDE-dG systems.     

COMPARISON OF THE SOLID-MATRIX LUMINESCENCE PROPERTIES AND PHOTOPHYSICAL PARAMETERS OF TWO PRODUCTS FROM BENZO(a)PYRENE-DNA ADDUCTS

Abstract: The solid-matrix luminescence properties and several calculated photophysical parameters of two important products from the benzo(a)pyrene-DNA adducts were compared. The products were benzo(a)pyrene-r-7,t-8,9,c-10-tetrahydrotetrol (I-1) and 7R,8S,9S-trihydroxy-10-( N ²-deoxyguanosyl-3'-phosphate)-7,8,9,10-tetrahydroben-zo(a)pyrene (BPDE-dG). The solid-matrix luminescence data were obtained for I-1 and BPDE-dG adsorbed on two different solid matrices, namely, 1%α-cyclodextrin (CD)/NaCl and 25% trehalose/NaCl and at two different temperatures (93 K and 296 K). The 25% trehalose/NaCl gave higher fluorescence and phosphorescence quantum yields from both I-1 and BPDE-dG in contrast to the 1%α-CD/NaCl matrix. The BPDE-dG showed lower fluorescence quantum yields on the solid matrices compared to I-1. The lower fluorescence quantum yields for BPDE-dG were attributed to a photoinduced electron transfer mechanism. In contrast to the room-temperature solution fluorescence of BPDE-dG, BPDE-dG gave rather high fluorescence quantum yields at room temperature when adsorbed on the two solid matrices. From solid-matrix luminescence quantum yields and solid-matrix luminescence lifetimes, many photophysical parameters were calculated and compared. Several differences among the rate constants were noted with the two solid matrices for BPDE-dG and I-1. For example, BPDE-dG showed internal conversion at 296 K with 25% trehalose/NaCl, but no internal conversion was observed at 93 K with this solid matrix. Also, for BPDE-dG the phosphorescence rate constants at 296 K and 93 K were very small with 25% trehalose/NaCl, but the intersystem crossing rate constants from the triplet state to the ground state were very large. The results from this work show how solid-matrix luminescence can be employed to obtain unique luminescence information from the I-1 and BPDE-dG systems.     

Luminescence Properties and Analytical Figures of Merit of the Tetrols of Benzo(A)Pyrene-Dna Adducts Adsorbed on α-, β- and γ- Cyclodextrin/Nacl Mixtures

Abstract

Several cyclodextrin/NaCl mixtures were investigated as solid matrices for obtaining room-temperature phosphorescence (RTP) and room-temperature fluorescence (RTF). The optimum experimental conditions for obtaining both RTF and RTP for the four tetrols were explored. Also, luminescence spectra, limits of detection, and linear ranges for calibration curves were acquired. This is the first report of the solid-matrix luminescence analytical figures of merit for the tetrols on cyclodextrin solid matrices.     

Acridine dyes in the triplet state as reagents for the selective luminescence determination of polycyclic aromatic hydrocarbons

The possibility of the selective determination of several polycyclic aromatic hydrocarbons (PAH) by sensitized room-temperature phosphorescence (SRTP) in sodium dodecylsulfate (SDS) micelles was studied. Acridine dyes (trypaflavine, acridine yellow, and acridine orange) were used as triplet-energy donors. It was found that the presence of external heavy atoms of thallium(I) is a prerequisite to SRTP in the system of an acridine dye (donor) and a PAH (acceptor). The linear concentration ranges, detection limits, and selectivity factors for the determination of pyrene, anthracene, and 1,2-benzanthracene by fluorimetry, room-temperature phosphorescence (RTP), and proposed SRTP were compared.     

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

Abstract

This is the first attempt for the direct detection of polycyclic aromatic hydrocarbon (PAH)-DNA adducts in human placental DNA samples by solid-matrix phosphorescence (SMP). Six samples were investigated, and SMP emission spectra and the corresponding second derivative SMP spectra were obtained for all the samples. Numerous excitation and emission wavelengths were studied for detecting PAH-DNA adducts. Second derivative SMP spectra indicated the presence of PAH-DNA adducts, whereas the longer SMP emission region proved fruitful for detecting adducts in the placental DNA samples. The SMP results for the samples strongly implied that a variety of PAH-DNA adducts could be present.     

A new sample cell design for studying solid-matrix room-temperature phosphorescence moisture quenching

A new sample chamber was developed that can be used in the measurement of the effects of moisture on the room-temperature solid-matrix phosphorescence of phosphors adsorbed onto filter paper. The sample chamber consists of a sealed quartz cell that contains a special teflon sample holder. Sulfuric acid solutions in the quartz cell determine the percentage relative humidity in the cell and also determine the amount of moisture adsorbed onto the filter paper. The new sample chamber is much easier to use than a flowing nitrogen gas system. Results from both systems are compared with respect to ease of use and the amount of moisture adsorbed onto the filter paper.     

A new analytical application of nylon-induced room-temperature phosphorescence: determination of thiabendazole in water samples

This paper discusses the first analytical determination of the widely used fungicide thiabendazole by nylon-induced phosphorimetry. Nylon was investigated as a novel solid-matrix for inducing room-temperature phosphorescence of thiabendazole, which was enhanced under the effect of external heavy-atom salts. Among the investigated salts, lead(II) acetate was the most effective in yielding a high phosphorescence signal. An additional enhancement of the phosphorescence emission was attained when the measurements were carried out under a nitrogen atmosphere. There was only a moderate increase in the presence of cyclodextrins. The room-temperature phosphorescence lifetimes of the adsorbed thiabendazole were measured under different working conditions and, in all cases, two decaying components were detected. On the basis of the obtained results, a very simple and sensitive phosphorimetric method for the determination of thiabendazole was established. The analytical figures of merit obtained under the best experimental conditions were: linear calibration range from 0.031 to 0.26 μg ml⁻¹ (the lowest value corresponds to the quantitation limit), relative standard deviation, 2.4% (n = 5) at a level of 0.096 μg ml⁻¹, and limit of detection calculated according to 1995 IUPAC Recommendations equal to 0.010 μg ml⁻¹ (0.03 ng/spot). The potential interference from common agrochemicals was also studied. The feasibility of determining thiabendazole in real samples was successfully evaluated through the analysis of spiked river, tap and mineral water samples.     

Solid-Phase microextraction with Whatman 1PS paper and direct room-temperature solid-matrix luminescence analysis

Solid-phase microextraction has been combined with solid-matrix luminescence for the detection of a variety of compounds at sub-nanogram levels for the first time. Whatman 1PS paper was placed in water solutions of polar and nonpolar compounds for the selective removal of the nonpolar compounds such as benzo(a)pyrene. Distribution constants were obtained for 4-phenylphenol, benzo(f)quinoline, benzo(h)quinoline, phenanthrene, and benzo(a)pyrene. The distribution constants showed that phenanthrene and benzo(a)pyrene in water had a very strong affinity for the 1PS paper. Once the solutes were extracted for a fixed period of time, the 1PS paper was dried, and either the solid-matrix fluorescence or solid-matrix phosphorescence was detected from the adsorbed lumiphors by using the appropriate excitation wavelengths. It was a simple matter to detect at least three adsorbed compounds on the 1PS paper by solid-matrix luminescence. Benzo(a)pyrene was easily detected at a level of 0.02 ng ml⁻¹ in water.     

Separation and characterization of tetrol metabolites of benzo[a]pyrene-DNA adducts using HPLC and solid-matrix room temperature luminescence

Four tetrols of benzo[a]pyrene-DNA adducts were separated using reversed-phase high performance liquid chromatography. Chromatographic fractions containing a given tetrol were readily characterized with solid-matrix room temperature luminescence techniques. Solid-matrix fluorescence and phosphorescence spectra at picogram amounts of a tetrol were easily obtained. Tetrol fractions collected based on retention times, but with no response from the ultraviolet detector, were characterized by solid-matrix luminescence spectra at very small quantities.     

Mass distribution for the microextraction of polycyclic aromatic hydrocarbon metabolites investigated with fluorescence spectrometry

Mass-balance data were acquired using fluorescence spectrometry for 2-naphthol and three polycyclic aromatic hydrocarbon (PAH) metabolites using liquid-liquid-liquid microextraction and liquid-liquid microextraction systems. The PAH metabolites are very important biomarkers, and there has been no previously reported mass-balance data on these compounds with microextraction systems. In addition, the effects of two solvent systems used in the preparation of donor and acceptor phases were investigated. The effects of the solvent systems on the partitioning process were compared. The mass balance results showed that significant amounts of the hydrophobic metabolites were held in the pores of the microfiber in both the three-phase and two-phase microextraction systems. Based on the mass-balance data, a new enrichment factor was defined as the concentration of the solute trapped in the pores of the fiber divided by the initial concentration of the solute in the donor phase. Because of the relatively large amount of the solute in the pores, it is envisioned that the solutes could be easily extracted from the pores, the extraction solvent concentrated, and further separated by capillary electrophoresis or characterized by solid-matrix phosphorescence, solution fluorescence, or mass spectrometry.     

A simple route to incorporate redox mediator into carbon nanotubes/Nafion composite film and its application to determine NADH at low potential

Several new sugar glasses were investigated for their potential in solid-matrix luminescence. Both solid-matrix fluorescence (SMF) and solid-matrix phosphorescence (SMP) properties were obtained, and two heterocyclic aromatic amines were employed as model compounds. In addition to glucose glasses, which were investigated previously, fructose, ribose, xylose, galactose, maltose, and glucose with poly(acrylic acid) (PAA) were studied. Detailed experimental conditions were obtained for each sugar-glass system. In addition, NaI was investigated as a heavy-atom salt in the sugar-glass systems to enhance the SMP of the heterocyclic aromatic amines. The SMF intensity was the strongest in maltose and glucose with PAA for 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and in maltose for 2-amino-9H-pyrido[2,3-b]indole (AαC). The largest SMP signals for PhIP with and without NaI were acquired in glucose with PAA. For AαC with NaI, the strongest SMP signal was obtained in maltose. Limits of detection were obtained for PhIP in the several sugar-glass systems, and the lowest limit of detection was 0.04 pmol/mg of PhIP in maltose with NaI present. An extensive study was carried out using both SMF and SMP to determine if neutral and/or protonated species of PhIP and AαC were in the sugar-glass systems. General guidelines such as glass transition temperature and solubility are discussed for selecting a sugar glass as a solid matrix.     

Supramolecular self-assembling strategy for constructing cucurbit[6]uril derivative-based amorphous pure organic room-temperature phosphorescence complex featuring extra-high efficiency

The preparation of amorphous pure organic room-temperature phosphorescence materials with high efficiency is still a challenging task. Herein, we introduce a CB[6] derivative-based supramolecular self-assembling strategy. A water soluble and ellipsoidal deformed CB[6] derivative is used to self-assemble with 4-(4-bromophenyl)-1-methylpyridin-1-ium chloride, bromide and hexafluorophosphate in water. After freeze-drying, the obtained amorphous complexes exhibit brilliant green phosphorescence emission under ambient conditions, with phosphorescence efficiency up to 59%, 60% and 72%, respectively. This is the first report of amorphous non-polymeric pure organic room-temperature phosphorescence with such a high efficiency. In view of the dynamic self-assembling property, the complexes are responsive to water, which could enable information encryption.     

Room-temperature phosphorescence of selecte aromatic carboxylic acids adsorbed on silica gel and polyacrylic acid—sodium chloride mixtures

Several aromatic carboxylic acids give room-temperature phosphorescence when adsorbed on silica gel chromatoplates that contain a polymeric binder. Terephthalic acid is used as a model compound to investigate the interactions with such chromatoplates and various polyacrylic acid sodium chloride mixtures. The results indicate that under some conditions, hydrogen bonding appears to be operative, whereas under other conditions room-temperature phosphorescence can be detected without hydrogen bonding interactions.     

Flow injection for continuous sample introduction in solid-substrate room-temperature phosphorescence

The feasibility of using flow injection as a continuous sample introduction method for solid-surface room-temperature phosphorescence (SSRTP) is studied. A two-nebulizer system is used to spray the heavy-atom and analyte solutions separately onto the moving filter-paper strip. The analytical figures of merit obtained for three well known phosphorescent compounds show that flow injection can be successfully employed in SSRTP methods.     

Time-resolved micelle-stabilized room-temperature phosphorimetry for simultaneous determination of gallium and indium

Ga(III) and In(III) react with 7-iodo-hydroxyquinoline-5-sulphonic acid (Ferron) in the presence of CTAB micelles, forming complexes which exhibit analytically useful room-temperature phosphorescence (RTP). The RTP features of the two complexes are similar and the RTP spectra overlap. However, there is sufficient difference between the two phosphorescence decay rates for both metals to be determined by time-resolved room-temperature phosphorimetry.     

Luminescence characteristics of dibenzofuran and several polychlorinated dibenzofurans and dibenzo-p-dioxins

The room-temperature fluorescence (RTP), low-temperature phosphorescence (LTP) and room-temperature phosphorescence (RTP) characteristics of dibenzofuran and several polychlorinated dibenzofurans and dibenzo-p-dioxins are presented and are shown to be suitable for the determination of these compounds. The limits of detection are as low as 0.02, 0.2 and 0.7 for RTF, LTP and RTP, respectively. The relative standard deviations are between 1 and 4% for RTP.