The design of new molecules for photochemical studies typically requires knowledge of spectral features of pertinent chromophores beginning with the absorption spectrum (λabs ) and accompanying molar absorption coefficient (e, m-1 cm-1 ) and often extending to the fluorescence spectrum (λem ) and fluorescence quantum yield (Φf ), where the fluorescence properties may be of direct relevance or useful as proxies to gain insight into the nature of the first excited singlet state. PhotochemCAD databases, developed over a period of 30 years, are described here. The previous databases for 150 compounds have been expanded to encompass 339 compounds for which absorption spectra (including e values), fluorescence spectra (including Φf values) and references to the primary literature have been included where available (552 spectra altogether). The compounds exhibit spectra in the ultraviolet, visible and/or near-infrared spectral regions. The compound classes and number of members include acridines (21), aromatic hydrocarbons (41), arylmethane dyes (11), azo dyes (18), biomolecules (18), chlorins/bacteriochlorins (16), coumarins (14), cyanine dyes (19), dipyrrins (7), heterocycles (26), miscellaneous dyes (13), oligophenylenes (13), oligopyrroles (6), perylenes (5), phthalocyanines (11), polycyclic aromatic hydrocarbons (16), polyenes/polyynes (10), porphyrins (34), quinones (24) and xanthenes (15). A database of 31 solar spectra also is included.

Database of Absorption and Fluorescence Spectra of >300 Common Compounds for use in PhotochemCAD.

A study on the sizes and concentrations of gold nanoparticles by spectra of absorption, resonance Rayleigh scattering and resonance non-linear scattering

This review paper presents the achievements and developments in the optical methods of antibiotic residues detection. The specific optical methods such as optical immunoassay methods, molecular spectroscopy detection methods, and optical fiber based detection methods are summarized in detail. And each of them was summarized and contrasted in a separate table, where the sensing structure, class of antibiotics and the limit of detection are all listed. Optical methods of antibiotic detections are widely used during the last two decades due to their short detection cycles, high sensitivity and simple operation, which are mainly researched for the food and water quality inspections. The future direction of sensing performances and application fields is also discussed.

Optical methods of antibiotic residues detections: A comprehensive review

From 1993 to 1995, with a conventional fluorescence spectrophotometer (CFS) (convenient) and working in a synchronous scan model (easy-to-use), Pasternack et al. proposed the resonance light-scattering (RLS) technique, to efficiently characterize self-assemblies or self-aggregations of chromophores with good electronic coupling. Incident wavelengths were specially considered within their absorption envelopes (rather unorthodox), and their amplified signals were observed (good sensitivity and selectivity). Due to these absorbing benefits, RLS technique, as a novel readout method, commenced on its exciting analytical tours soon after Liu et al. and especially Li et al., separately, set out their corresponding pioneering investigations from 1995 to 1997. From then on, it has received an increasing attention by analysts, as a consequence exhibiting more and more fascinating analytical applications. Moreover, various attractive RLS-derived techniques have been developed successively to improve it or to enlarge its possibilities. Later on, Liu et al. and Li et al., Tabak et al., Yguerabide et al., Huang et al., Lakowicz et al. and Fernandez Band et al. have made their outstanding contributions. In this review, we concentrate on major achievements of RLS in analytical chemistry for over a decade, involving the developments and analytical applications of RLS derived techniques treated as an impacting progress of RLS technique in analytical chemistry. Finally, an indication of future directions of RLS technique in analytical chemistry is provided.

Resonance light scattering and derived techniques in analytical chemistry: past, present, and future

A review of the sources of uncertainties in atmospheric mercury modeling II. Mercury surface and heterogeneous chemistry – A missing link

The composition and existing species of the reaction production of Hg 2+ and X - . (X= Cl, Br and I) under different conditions, and their absorption, Rayleigh scattering (RS) and resonance Rayleigh scattering (RRS) spectra have been studied. The results show that the products exist in the form of nanoparticles as [HgX 2 ] n aggregates under suitable conditions, and their average diameters increase with the increase of X- diameters. The diameters of [HgCl 2 ] n , [HgBr 2 ] n and [HgI 2 ] n are less than 4 nm, equal to 9 nm and 70 nm respectively. There are bathchromic shifts gradually with the increase of X- diameters in their absorption spectra. The absorption bands of [HgCl 2 ] n and [HgBr 2 ] n locate at ultraviolet region. However, the absorption band of [HgI 2 ] n is obvious in visible light region. Among three particles, only [HgI 2 ] n exhibits a strong RRS and its scattering peak is at 580 nm. The main reasons leading to the enhancement of resonance scattering are the large size of nanoparticle, the formation of the interface and the location of light scattering in the absorption band. There are three important factors affecting resonance scattering spectrum: the quanta colored effect and molecular absorption spectrum of [HgI 2 ] n nanoparticle as well as instrumental factors which mainly include the light source’s emission spectral characteristics and the signal response curve of detector.

Absorption and Rayleigh scattering and resonance Rayleigh scattering spectra of (HgX2)n nanoparticles

Studies on the resonant luminescence spectra of rhodamine dyes and their ion-association complexes

In pH 4.2–5.0 Britton-Robinson buffer solution medium, fluoroquinolone antibiotics (FLQs), such as ciprofloxacin (CIP), norfloxacin (NOR), ofloxacin (OF), levofloxacin (LEV), lomefloxacin (LOM), and sparfloxacin (SPA), react with Cu (II) to form chelate cations, which further bind with erythrosine to form the ion association complexes. They can result in the changes of the absorption spectra. Simultaneously, erythrosine fades obviously and the maximum fading wavelength is located at 526 nm. The fading reactions have high sensitivities. Thus, new spectrophotometries of determination for these drugs are developed. The ion-association reactions result in the quenching of fluorescence, which also have high sensitivities. The detection limits for six antibiotics are in the range of 7.1–12.2 μg·L−1. Furthermore, the reactions can result in the enhancement of resonance Rayleigh scattering (RRS). The maximum scattering peaks of six ion-association complexes are located at 566 nm, and there are two small RRS peaks at 333 nm and 287 nm. The detection limits for fluoroquinolone antibiotics are in the range of 1.70–3.10 μg·L−1 for RRS method. Among the above three methods, the RRS method has the highest sensitivity. In this work, we investigated the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reactions, and the properties of the analytical chemistry. In addition, the mechanism of reactions were discussed by density function theory (DFT) and AM1 methods.

Study on the absorption and fluorescence and resonance Rayleigh scattering spectra of Cu (II)-fluoroquinolone chelates with erythrosine and their applications

Binding of heparin with methylene blue (MB) in pH 5.7 Britton-Robinson buffer can result in a significant enhancement of frequency doubling scattering (FDS) and second-order scattering (SOS). Their maximum scattering wavelengths (λmax) appear at 350 nm for EDS and 700 nm for SOS, respectively. The optimum conditions of the reaction, the influencing factors and the relationship between the two scattering intensities and the concentration of heparin have been investigated. The new methods for the determination of trace amounts of heparin based on the FDS and SOS methods have been developed, which exhibit high sensitivities. The detection limits of heparin are 4.36 ng/mL for the FDS method and 3.55 ng/mL for the SOS method, respectively. Both of the methods have fairly good selectivity and were applied to the determination of heparin in sodium heparinate injection samples with satisfactory results. Moreover, the relative mechanisms have also been discussed.

Study on Frequency Doubling Scattering and Second‐Order Scattering Spectra of Heparin‐Methylene Blue System

The interaction between congo red (CR) and amikacin (AMK) was studied by resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS) and second-order scattering (SOS) combining with absorption spectrum. In a weak acidic medium, CR combined with AMK to form an ion association complex with the composition ratio of 1∶1 by electrostatic interaction, hydrophobicity and charge transferring effect. As a result, the new spectra of RRS, FDS, and SOS appeared and their intensities were enhanced greatly. The maximum wavelengths of RRS, FDS and SOS were located at 563 nm, 475 nm and 940 nm, and the scattering intensities were proportional to the concentration of AMK. These three methods have very high sensitivities, and the detection limits were 4.0 ng·mL -1 for RRS, 3.6 ng·mL -1 for FDS and 1.9 ng·mL -1 for SOS, respectively. At the same time, the methods have better selectivity. A new method for the determination of trace amounts of AMK with congo red by resonance scattering technique has been developed. The recovery for the determination of AMK in blood serum and urine sample was between 95.5% and 105.5%. In this study, the properties, such as enthalpy of formation, charge distribution and mean polarizability, were calculated by AM1 quantum chemistry method. In addition, the reaction mechanism and the reasons for the enhancement of scattering spectra were discussed.

Liu Shaopu

Papers

Absorption and Rayleigh scattering and resonance Rayleigh scattering spectra of (HgX2)n nanoparticles

Studies on the resonant luminescence spectra of rhodamine dyes and their ion-association complexes

Study on the absorption and fluorescence and resonance Rayleigh scattering spectra of Cu (II)-fluoroquinolone chelates with erythrosine and their applications

Study on Frequency Doubling Scattering and Second‐Order Scattering Spectra of Heparin‐Methylene Blue System

Study on the resonance Rayleigh scattering spectra and resonance non-linear spectra of congo red-amikacin system and its analytical application