UV Spectral Characteristics Research Articles

Investigation on the ultraviolet spectral radiation characteristics of two-phase flow plume based on OH and alumina particles.

Ultraviolet detection has advantages over radar and infrared detection, such as low background radiation and high resolution. The UV spectral radiation characteristics of exhaust plume are of extremely great research significance as the main parameters for aircraft detection. We used the BEM-2 two-phase flow plume as the object of study, calculated the scattering characteristics of alumina particles and the UV absorption coefficient of OH in the plume based on the MIE theory and the line-by-line integration method, established the UV radiation transfer model of aircraft plume under gas-solid coupling, simulated the UV spectral radiation characteristics of the plume, and compared them with experimental results. The results show that due to the drastic changes of temperature and pressure at the Mach and non-Mach disks in the plume, the value of OH absorption coefficient fluctuates up and down along the axial direction with the position of the Mach disk; at 261nm, 282nm, and 306nm, the spectral radiation intensity of alumina particles accounts for approximately 96%, 85%, and 73% of the total spectral radiation intensity of the plume, respectively, which are much higher than the proportion of OH gas spectral radiation intensity, but in the infrared wave band, the influence of particle scattering characteristics on the spectral radiation intensity of the plume is much lower compared to the UV wave band; the overall radial range of the UV spectral radiation intensity of the plume is relatively narrow and its tail exhibits a converging shape, showing a good consistency with the experimental results.

Influences of Mn2+/Eu3+ dopants on the microstructures and optical properties of glass-embedded CsPbBr3 quantum dots

All inorganic CsPbX3 (X = Cl, Br, I) perovskite quantum dots (PQDs) exhibit excellent photoelectric properties, such as high photoluminescence quantum yield, exceptional defect tolerance, and a long carrier diffusion length. However, their poor stability limits their applications. In this study, CsPbBr3 PQDs were precipitated in a phosphate glass matrix by a melt quenching method. The influences of Mn2+ and Eu3+ dopants on the microstructure and optical properties of CsPbBr3 PQDs glass were investigated in detail. The DSC and XRD results reveal that Mn2+/Eu3+ can act as a nucleating agent to promote the precipitation of CsPbBr3 PQDs in the glass matrix and optimize its microstructure. Simultaneously, PL spectra shows that appropriate Mn2+/Eu3+ doping concentration can enhance the optical performance of CsPbBr3 PQDs glass. The luminescence intensity increases by 46.9% and 44.3%, respectively, with the additions of these dopants. Finally, Mn2+ and Eu3+ single-doped CsPbBr3 PQDs glass is proved to have excellent broadband UV spectral response characteristics, indicating its potential application for photoelectric detection.

Isolation and Biochemical Properties of Type II Collagen from Blue Shark (Prionace glauca) Cartilage

Numerous studies have shown that type II collagen (CII) has a potential role in the treatment of rheumatoid arthritis. However, most of the current studies have used terrestrial animal cartilage as a source of CII extraction, with fewer studies involving marine organisms. Based on this background, collagen (BSCII) was isolated from blue shark (Prionace glauca) cartilage by pepsin hydrolysis and its biochemical properties including protein pattern, total sugar content, microstructure, amino acid composition, spectral characteristics and thermal stability were further investigated in the present study. The SDS-PAGE results confirmed the typical characteristic of CII, comprising three identical α1 chains and its dimeric β chain. BSCII had the fibrous microstructure typical of collagen and an amino acid composition represented by high glycine content. BSCII had the typical UV and FTIR spectral characteristics of collagen. Further analysis revealed that BSCII had a high purity, while its secondary structure comprised 26.98% of β-sheet, 35.60% of β-turn, 37.41% of the random coil and no α-helix. CD spectra showed the triple helical structure of BSCII. The total sugar content, denaturation temperature and melting temperature of BSCII were (4.20 ± 0.03)%, 42 °C and 49 °C, respectively. SEM and AFM images confirmed a fibrillar and porous structure of collagen and denser fibrous bundles formed at higher concentrations. Overall, CII was successfully extracted from blue shark cartilage in the present study, and its molecular structure was intact. Therefore, blue shark cartilage could serve as a potential source for CII extraction with applications in biomedicine.

Analysis of 12/15-lipoxygenase metabolism of EPA and DHA with special attention to authentication of docosatrienes

A proposed beneficial impact of highly unsaturated “fish oil” fatty acids is their conversion by lipoxygenase (LOX) enzymes to specialized proresolving lipid mediators, including 12/15-LOX products from EPA and DHA. The transformations of DHA include formation of docosatrienes, named for the distinctive conjugated triene of the double bonds. To further the understanding of biosynthetic pathways and mechanisms, herein we meld together biosynthesis and NMR characterization of the unstable leukotriene A (LTA)-related epoxide intermediates formed by recombinant human 15-LOX-1, along with identification of the stable enzymatic products, and extend the findings into the 12/15-LOX metabolism in resident murine peritoneal macrophages. Oxygenation of EPA by 15-LOX-1 converts the initial 15S-hydroperoxide to 14S,15S-trans-epoxy-5Z,8Z,10E,12E,17Z-EPA (appearing as its 8,15-diol hydrolysis products) and mixtures of dihydroperoxy fatty acids, while mainly the epoxide hydrolysis products are evident in the murine cells. DHA also undergoes transformations to epoxides and dihydroperoxides by 15-LOX-1, resulting in a mixture of 10,17-dihydro(pero)xy derivatives (docosatrienes) and minor 7S,17S- and 14,17S-dihydroperoxides. The 10,17S-dihydroxy hydrolysis products of the LTA-related epoxide intermediate dominate the product profile in mouse macrophages, whereas (neuro)protectin D1, the leukotriene B4-related derivative with trans,trans,cis conjugated triene, was undetectable. In this study, we emphasize the utility of UV spectral characteristics for product identification, being diagnostic of the different double bond configurations and hydroxy fatty acid functionality versus hydroperoxide. LC-MS is not definitive for configurational isomers. Secure identification is based on chromatographic retention times, comparison with authentic standards, and the highly distinctive UV spectra.

Characteristics of Fluorescence Spectra, UV Spectra, and Specific Growth Rates during the Outbreak of Toxic Microcystis Aeruginosa FACHB-905 and Non-Toxic FACHB-469 under Different Nutrient Conditions in a Eutrophic Microcosmic Simulation Device

Microcystis aeruginosa is the dominant alga forming cyanobacteria blooms, the growth of which is limited by available nutrients. Thus, it is necessary to study cyanobacteria blooms and explore the growth of Microcystis aeruginosa under different nutrient conditions. In this paper, we take Microcystis aeruginosa, including toxic Freshwater Algae Culture of Hydrobiology Collection (FACHB)-905 and non-toxic FACHB-469 strains, into account. The strains were cultured using a simulation device under different nutrient conditions. Ultraviolet spectra, three-dimensional fluorescence spectra, and kinetic parameter indicators of the two species are studied. Compared to FACHB-469, the results show that the specific growth rate of FACHB-905 is much higher, in particular, FACHB-905 is the dominant species under low nutrient conditions. Furthermore, the UV spectral characteristics indicate that the molecular weight of dissolved organic matter in the culture tank of toxic FACHB-905 is greater than that of FACHB-469. Additionally, the humification index of toxic FACHB-905 is slightly higher as well, which suggests that it is more stable in the presence of dissolved organic matter during blooms. Therefore, the toxic Microcystis strain is more likely to become the dominant species in water blooms under lower eutrophic conditions and water blooms formed by the toxic Microcystis strain may be more difficult to recover from.

A Spectral-Luminescence Study of Biologically Active 2-Amino-1,3-Thiazoles Containing a Diterpene Fragment in Acetonitrile Solutions

A spectral-luminescence study of a number of 2-amino-1,3-thiazoles containing a diterpene fragment has been carried out. The test compounds were prepared based on the chemical conversion of maleopimaric acid; they exhibit a wide range of biological activities: antitumor, antimicrobial, and antioxidant ones. Their UV spectral and fluorescence characteristics and the quantum yields of luminescence in acetonitrile solutions have been determined. The rule of mirror symmetry in the absorption and fluorescence spectra of the obtained compounds has been found to be violated.

Simultaneous photoaddition, photoreduction and chemical reduction of riboflavin by sulfur containing dianions: A kinetic study

The present investigation involves the evaluation of the effect of reducing dianions (SO32−, S2O32−, S2O52−) on the kinetics of simultaneous photoaddition, photoreduction and chemical reduction reactions of riboflavin (RF) at pH 6–8. The photoproducts of these reactions have been identified and assayed during the degradation of RF. The final products of the above reactions are cyclodehydroriboflavin (CDRF), lumichrome (LC) and dihydroriboflavin (DHRF), respectively. The first-order rate constants for the loss of RF (kobs) (0.61–3.07 × 10-3 min-1) and formation of photoproducts (0.21–1.61 × 10-3 min-1) in the presence of dianions (0.2–1.0 M), and the second-order rate constants for the photochemical interaction of RF and dianions (1.42–2.01 × 10-3 M-1 min-1) and for the chemical reduction of RF (dark) (2.31–3.25 × 10-3 M-1 min-1) have been determined. The UV and visible spectral and fluorescence characteristics of RF in the presence of dianions have been studied. The fluorescence of RF is quenched by dianions depending upon the extent of their interaction with the molecule. The photoaddition of RF is optimum under neutral pH conditions and is catalyzed by the dianions in the order: S2O52− > SO32− > S2O32−, whereas the chemical reduction is enhanced in the reverse order. The S2O32− dianion is most effective as a reducing agent on the basis of its redox potential which is lower than that of the SO32−dianion. The quantum yields of photodegradation of RF in the presence of dianions (0.018–0.046) have been determined. The mode of photodegradation reactions of RF has been discussed.

Computational Study of the Interactions between Benzene and Crystalline Ice Ih : Ground and Excited States.

Ground-state geometries of benzene on crystalline ice cluster model surfaces (Ih ) are investigated. It is found that the binding energies of benzene-bound ice complexes are sensitive to the dangling features of the binding sites. We used time-dependent DFT to study the UV spectroscopy of benzene, ice clusters, and benzene-ice complexes, by employing the M06-2X functional. It is observed that the size of the ice cluster and the dangling features have minor effects on the UV spectral characteristics. Benzene-mediated electronic excitations of water towards longer wavelengths (above 170 nm) are noted in benzene-bound ice clusters, where the cross-section of photon absorption by water is negligible, in good agreement with recent experimental results (Thrower et al., J. Vac. Sci. Technol. A, 2008, 26, 919-924). The intensities of peaks associated with water excitations in benzene-ice complexes are found to be higher than in isolated ice clusters. The π→π* electronic transition of benzene in benzene-ice complexes undergoes a small redshift compared with the isolated benzene molecule, and this holds for all benzene-bound ice complexes.

Interaction of adriamycin with a regulatory element of hmgb1: spectroscopic and calorimetric approach

HMGB1 is a non-histone nuclear protein which plays important role in transcription, variable, diverse and joining (VDJ) recombination, chromatin remodeling, and DNA repair, etc. and its over expression is directly correlated with various human malignancies and inflammatory diseases. Because of the clear association between HMGB1 and cancer, we studied the binding of adriamycin (ADM), a well-known anticancer drug with the promoter region (−165 to −183) of hmgb1 by using a variety of spectroscopic, calorimetric techniques, and in-silico molecular modeling. Changes in UV and CD spectral characteristics (intensity and wavelength) of ADM and DNA associated with an induced peak (300 nm) in CD spectrum of DNA and a high binding constant of 2.0 × 105 M−1 suggest a strong and stable complex formation between DNA and ADM. Scatchard analysis of spectroscopic data indicate that ADM binds to DNA in a non-cooperative nature. Further the quenching of fluorescence emission of ADM and isothermal titration calorimetry of ADM in presence of DNA points out to the intercalative mode of ADM binding to DNA which is enthalpically driven with additional small entropic contribution. Results from molecular modeling, Isothermal titration calorimetry, and Fourier transform infrared spectroscopy reveal that ADM has no marked preference between AT vs. GC base pair in binding to DNA. Therefore, hmgb1 can be considered as a novel potential chemotherapeutic target in treating cancers associated with HMGB1 upregulation.

Determinação do perfil fitoquímico de extrato com atividade antioxidante da espécie medicinal Cordia verbenacea DC. por HPLC-DAD

O presente trabalho teve por objetivo investigar a atividade antioxidante dos extratos das folhas de Cordia verbenacea obtido por maceração em etanol e partição em solventes orgânicos. O infuso das folhas também foi investigado. O teor de fenóis totais foi avaliado pelo método de Folin-Ciocalteau e o de flavonoides totais pela formação de complexo com cloreto de alumínio. O extrato etanólico, as subfrações e o infuso foram testados em diversas concentrações para determinar a atividade sequestradora de DPPH expressa em termos de sua CE50. A melhor atividade antioxidante encontrada foi para o extrato em acetato de etila, EA, CE50 15,0 ± 0,5 µg.mL-1. Os ensaios espectrofotométricos revelaram altas concentrações de fenóis e de flavonoides no extrato EA. A análise por HPLC-DAD foi realizada para se obter o perfil de UV-Vis dos picos cromatográficos do extrato EA. As características espectrais foram relacionadas a compostos fenólicos e flavonoídicos.

Study on Active Compounds of <i>Apocynum venetum</i> L

Although Apocynum leaves have been used for the treatment of cardiovascular diseases, the study on active compounds of Apocynum venetum L. is little. In this paper,high performance liquid chromatography with mass spectrometry (HPLC-MS) were used for the active ingredient in qualitative analysis of Apocynum leaves, based on the information of the mass spectrum molecular ion peak [M-and some characteristic fragment ions, and combined with UV spectral characteristics we initially speculated that Apocynum leaves water extract isolated to 10 components.

GMASS ultradeep spectroscopy of galaxies atz ~ 2

We use rest-frame UV spectroscopy to investigate the properties related to large-scale gas outflows, and to the dust extinction and star-formation rates of a sample of z ~ 2 star-forming galaxies from the Galaxy Mass Assembly ultradeep Spectroscopic Survey (GMASS). Dust extinction is estimated from the rest-frame UV continuum slope and used to obtain dust-corrected star-formation rates for the galaxies of the sample. For the entire sample, a mean value of the continuum slope <\beta> = -1.11 \pm 0.44 (r.m.s.) was derived, while the average SFR was found to be <SFR> = 52 \pm 48 M_sun/yr (r.m.s.). A positive correlation between SFR and stellar mass was observed, in agreement with other works, the logarithmic slope of the relation being 1.10 \pm 0.10. Low-ionization absorption lines, associated with the interstellar medium, were found to be blueshifted, with respect to the rest frame of the system, which indicates that there is outflowing gas with typical velocities of the order of ~ 100 km/s. Finally, investigating correlations between galaxy UV spectral characteristics and galaxy general properties, we report a possible correlation between the equivalent width of the interstellar absorption lines and SFR, stellar mass, and colour excess similar to that seen to hold at different redshifts.

Phenolic compounds from Potentilla anserina

Silverweed (Potentilla anserina L.) is one of the most common species of the genus Potentilla in the flora of Ukraine. Decoctions, tinctures, and infusions of this plant exhibit antibacterial, thromboplastic, antifibrinolytic, and other types of activity. The aerial part of the plant contains phenolcarboxylic and hydroxycinnamic acids, flavonoids (1.8%), coumarins, catechins, leucocyanidins, anthocyanins, and tanning agents, in the aerial part up to 10.64%; in the subterranean part, up to 25% [1]. The component composition of essential oils from the aerial and subterranean parts and the antimicrobial activity of the EtOH extract were previously established. The quantitative contents of chlorophylls, flavonoids, and carotinoids in the extract were determined [2–5]. TLC of P. anserina herb collected before flowering contained 14 phenolic compounds [6]. In continuation of this research, we studied phenolic compounds from the subterranean and aerial parts of the plant. We studied herb collected before flowering and rhizomes with roots collected in Kharkov in June 2009. Chromatography and identification of the phenolic compounds were carried out as before [7]. As a result, ellagic acid (1), myricetin-3-O-glucoside (2), rutin (3), quercetin-3-O-glucoside (4), and quercetin-3-O-arabinoside (5) were identified in the aerial part of silverweed. Four ellagic acid derivatives (EAD, 6–9) were observed for the first time in the subterranean parts of silverweed. These were identified by retention times and characteristics of their UV spectra. UV spectra of 6–9 differed from that of ellagic acid by hypsochromic shifts of long-wavelength band maxima. The maximum for ellagic acid was observed at 369 nm; EAD 6, 356; EAD 7, 362; EAD 8, 356; and EAD 9, 359. Furthermore, additional maxima at 340–345 nm were noted in UV spectra of EADs 1 and 3. Considering the shorter retention times for these compounds than for ellagic acid and their UV spectral characteristics, it was assumed that they were glucosylated derivatives (ellagotannins). The acid hydrolysis products of the MeOH extract of rhizomes included glucose according to chromatography and ellagic acid according to HPLC (Table 1). Myricetin-3-O-glucoside (0.16%) and rutin (0.10%) dominated the aerial part; ellagic acid (0.01%), the subterranean part.

Solvent polarity effect on the composition of biologically active substances, UV spectral characteristics, and antibacterial activity of Euphrasia brevipila herb extracts

The compositions of biologically active substances in Euphrasia brevipila Burn. et Gremli (Scrophulariaceae) extracts obtained using solvents with different polarities have been investigated. It was established that the composition of isolated substances varied depending on the extractant polarity. Only phenolcarboxylic acids were found in ether, chloroform, and ethylacetate extracts. Aqueous, ethanol, and DMSO extracts contained also flavonoids and iridoids. The difference in the compositions of biologically active substances was confirmed by UV spectral characteristics of extract solutions with added complexants. The maximum antibacterial activity with respect to Staphylococcus aureus and Escherichia coli was observed for extracts obtained using the nonpolar solvents petroleum ether and chloroform (in 1:320 dilution). The bacteriostatic activity of the extracts decreases with increasing solvent polarity in the order n-butanol—ethanol—water—DMSO.

Study of degradation profile and development of stability indicating methods for cefixime trihydrate

The degradation behavior of cefixime trihydrate was investigated under different stress conditions of acidic hydrolysis, alkaline hydrolysis and oxidation using spectrophotometry. Stability indicating spectrophotometric methods were developed that could separate the drug from its degradation products formed under these stress conditions. The UV spectral characteristics of the drug and degraded products were quite different and zero and first order derivative ultraviolet spectrophotometric methods were used to study the extent of degradation. Cefixime trihydrate was found to degrade extensively under experimental conditions. The methods were validated by establishing the linearity, inter and intraday precision, accuracy, selectivity and specificity.

Structural characterization of constituents with molecular diversity in fractions from Lysidice brevicalyx by liquid chromatography/diode‐array detection/electrospray ionization tandem mass spectrometry and liquid chromatography/nuclear magnetic resonance

A combination of electrospray ionization tandem mass spectrometry with high-performance liquid chromatography (HPLC/ESI-MSn), and hyphenation of liquid chromatography to nuclear magnetic resonance spectroscopy (HPLC/NMR), have been extensively utilized for on-line analysis of natural products, analyzing metabolite and drug impurity. In our last paper, we reported an on-line analytical method for structural identification of trace alkaloids in the same class. However, the structural types of the constituents in plants were various, such as flavanoids, terpenoids and steroids. It is important to establish an effective analytical method for on-line structural identification of constituents with molecular diversity in extracts of plants. So, in the present study, the fragmentation patterns of some isolated stilbenes, phloroglucinols and flavanoids from Lysidice rhodostegia were investigated by ESI-MSn. Their fragmentation rules and UV characteristics are summarized, and the relationship between the spectral characteristics, rules and the structures is described. According to the fragmentation rules, NMR and UV spectral characteristics, 24 constituents of different types in the fractions from L. brevicalyx of the same genus were structurally characterized on the basis of HPLC/HRMS, HPLC-UV/ESI-MSn, HPLC/1H NMR and HPLC/1H-1H COSY rapidly. Of these, six (10, 13, 14, 16, 17 and 23) are new compounds and all of them are reported from L. brevicalyx for the first time. The aim is to develop an effective analytical method for on-line structural identification of natural products with molecular diversity in plants, and to guide the rapid and direct isolation of novel compounds by chemical screening.

Identification of a new C 28H 14 polycyclic aromatic hydrocarbon as a product of supercritical fuel pyrolysis: Tribenzo[ cd,ghi,lm]perylene

Tribenzo[ cd,ghi,lm]perylene has been identified as a product of the supercritical pyrolysis of both toluene and Fischer–Tropsch synthetic jet fuel. This identification is based on HPLC/UV/MS data, which show that compound I, eluting immediately after five other C 28H 14 isomers, is also a C 28H 14 PAH. The UV spectrum of compound I has features of a benzenoid PAH, of which there are only eight C 28H 14 isomers. Four of these isomers – benzo[ a]coronene, phenanthro[5,4,3,2- efghi]perylene, benzo[ cd]naphtho[3,2,1,8- pqra]perylene, and benzo[ pqr]naphtho[8,1,2- bcd]perylene – have already been identified as supercritical pyrolysis products by matching their UV spectra with those of respective reference standards. A fifth C 28H 14 PAH – benzo[ ghi]naphtho[8,1,2- bcd]perylene, which does not have a reference standard – has also been recently identified through MS and UV data, use of annellation theory to predict UV spectral characteristics, and length-to-breadth ratio/retention time data. Of the remaining three isomers, bisanthene (IUPAC name phenanthro[1,10,9,8- opqra]perylene) has been determined not to be present in our product mixture, as its UV spectrum does not match that of any of our product PAH. Using annellation theory, we predict the UV spectral characteristics of the two remaining C 28H 14 benzenoid isomers, for which there are no reference standards (tribenzo[ cd,ghi,lm]perylene and naphthaceno[3,4,5,6,7- defghij]naphthacene). Results from this analysis show that the predicted UV spectral features of tribenzo[ cd,ghi,lm]perylene match those of compound I—and that those of naphthaceno[3,4,5,6,7- defghij]naphthacene are inconsistent with those of compound I. The length-to-breadth ratio of tribenzo[ cd,ghi,lm]perylene also agrees with compound I's HPLC elution behavior. This is the first time that tribenzo[ cd,ghi,lm]perylene (IUPAC name phenanthro[2,1,10,9,8,7- pqrstuv]pentaphene) has been identified as a product of fuel pyrolysis or combustion.

Physical parameters and wind properties of galactic early B supergiants

We present optical studies of the physical and wind properties, plus CNO chemical abundances, of 25 09.5-B3 Galactic supergiants. We employ non-LTE, line blanketed, extended model atmospheres, which provide a modest downward revision in the effective temperature scale of early B supergiants of up to 1-2 kK relative to previous non-blanketed results. The so-called bistability jump at Bl (T eff ∼ 21 kK) from Lamers et al. is rather a more gradual trend (with large scatter) from v∞ /v esc ∼ 3.4 for B0-0.5 supergiants above 24 kK to v∞/v esc ∼ 2.5 for B0.7-1 supergiants with 20 kK ≤T ew ≤ 24 kK, and v∞/v esc ∼ 1.9 for B1.5-3 supergiants below 20 kK. This, in part, explains the break in observed UV spectral characteristics between B0.5 and B0.7 subtypes as discussed by Walborn et al. We compare derived (homogeneous) wind densities with recent results for Magellanic Cloud B supergiants and generally confirm theoretical expectations for stronger winds amongst Galactic supergiants. However, winds are substantially weaker than predictions from current radiatively driven wind theory, especially at midB subtypes, a problem which is exacerbated if winds are already clumped in the Ha line forming region. In general, CNO elemental abundances reveal strongly processed material at the surface of Galactic B supergiants, with mean N/C and N/O abundances 10 and 5 times higher than the Solar value, respectively, with HD 2905 (BC0.7 Ia) indicating the lowest degree of processing in our sample, and HD 152236 (B1.5 Ia + ) the highest.

UV and fluorescence spectral characteristics of Ciprofloxacin-Betacyclodextrin inclusion complex

Enhanced UV absorption (a = 4.4 fold) and fluorescence emission (k = 4.6 fold) was observed in the case of Ciprofloxacin on complexation with Betacyclodextin (1 : 1 M). This could enhance the precession in the analysis ofCiprofloxacin in formulations or biological samples for bio-availability studies.

Aspartame: studies on UV spectral characteristics

SummaryModel experiments were done by using aspartame (APM) solutions containing organic acids, such as malic, tartaric and citric acids, before and after heating at 80 °C for 1 h. Ultra violet spectral data was gathered and indicated an increase in λmax as well as the general absorbance with increasing concentration of APM. Spectra were recorded for both APM and its degradation products in water and 0.01% HCl and also before and after heating. The quantitation of APM by this spectral method was found to be comparable with that obtained by an HPLC method. Spectra were recorded for concentrations of 0.25–5 mm APM solutions between 200 and 400 nm. Linear, semi‐log and polynomial equations were found to give good fits to the observed data with major and minor peaks in both normal and derivative spectral modes. Beverages containing lemon juice showed higher λmax and absorbance values than normal with APM present. The results indicated that UV spectrophotometry could be used to monitor changes in APM concentration during processing and/or storage, and could indicate the presence or absence of APM polymorphism in solution.