Estimating mean molecular weight, carbon number, and OM∕OC with mid-infrared spectroscopy in organic particulate matter samples from a monitoring network

Organic matter (OM) is a major constituent of fine particulate matter, which contributes significantly to degradation of visibility and radiative forcing, and causes adverse health effects. However, due to its sheer compositional complexity, OM is difficult to characterize in its entirety. Mid-infrared spectroscopy has previously proven useful in the study of OM by providing extensive information about functional group composition with high mass recovery. Herein, we introduce a new method for obtaining additional characteristics such as mean carbon number and molecular weight of these complex organic mixtures using the aliphatic C−H absorbance profile in the mid-infrared spectrum. We apply this technique to spectra acquired non-destructively from Teflon filters used for fine particulate matter quantification at selected sites of the Inter-agency Monitoring of PROtected Visual Environments (IMPROVE) network. Since carbon number and molecular weight are important characteristics used by recent conceptual models to describe evolution in OM composition, this technique can provide semi-quantitative, observational constraints of these variables at the scale of the network. For this task, multivariate statistical models are trained on calibration spectra prepared from atmospherically relevant laboratory standards and are applied to ambient samples. Then, the physical basis linking the absorbance profile of this relatively narrow region in the mid-infrared spectrum to the molecular structure is investigated using a classification approach. The multivariate statistical models predict mean carbon number and molecular weight that are consistent with previous values of organic-mass-to-organic-carbon (OM/OC) ratios estimated for the network using different approaches. The results are also consistent with temporal and spatial variations in these quantities associated with aging processes and different source classes (anthropogenic, biogenic, and burning sources). For instance, the statistical models estimate higher mean carbon number for urban samples and smaller, more fragmented molecules for samples in which substantial aging is anticipated.

Time-absorbance profile ratio background correction: introducing TAP to correct for spectral overlap in high-resolution continuum source graphite furnace atomic absorption spectrometry

A new method to correct for spectral overlap when using HR CS GFAAS is proposed.

Linking Anthocyanin Diversity, Hue, And Genetics In Purple Corn

While maize with anthocyanin-rich pericarp (purple corn) is rising in popularity as a source of natural colorant for foods and beverages, information on color range and stability—factors associated with anthocyanin decorations and compositional profiles—are currently limited. Using the natural anthocyanin diversity present in a purple corn landrace, Apache Red, we generated a population with variable flavonoid profiles—flavonol-anthocyanin condensed forms (0-83%), acylated anthocyanins (2-72%), pelargonidin-derived anthocyanins (5-99%), and C-glycosyl flavone co-pigments up to 1904 µg/g—all of which contributed in part to the absorbance profile, used here as a proxy for hue. This variability offers targets of selection for breeders looking to expand both stability and the available range of colors that can be sourced from purple corn. With genotyping-by-sequencing of this population we mapped these anthocyanin profile traits. Major QTL for anthocyanin type were found near loci previously identified only in aleurone-pigmented maize varieties [Purple aleurone1 (Pr1) and Anthocyanin acyltransferase1 (Aat1)]. A QTL near P1 (Pericarp color1) was found for both flavone content and flavanol-anthocyanin condensed forms. A significant QTL associated with peonidin-derived anthocyanins near a candidate S-adenosylmethionine-dependent methyltransferase was also identified, warranting further investigation. This population represents the most anthocyanin diverse pericarp-pigmented maize variety characterized to date. Moreover, the candidates identified here will serve as branching points for future research studying the genetic and molecular processes determining anthocyanin profile in pericarp.

Estimating mean molecular weight, carbon number, and OM/OC with mid-infrared spectroscopy in organic particulate matter samples from a monitoring network

Organic matter (OM) is a major constituent of fine particulate matter which contributes significantly to degradation of visibility, radiative forcing, and causes adverse health effects. However, due to its sheer compositional complexity, OM is difficult to characterize in its entirety. Mid-infrared spectroscopy has previously proven useful in the study of OM by providing extensive information about functional group composition with high mass recovery. Herein, we introduce a new method for obtaining additional characteristics such as mean carbon number and molecular weight of these complex organic mixtures using the aliphatic C–H absorbance profile in mid-infrared spectrum. We apply this technique to spectra acquired non-destructively from Teflon filters used for fine particulate matter quantification at selected sites of Inter-agency Monitoring of PROtected Visual Environments (IMPROVE) network. Since carbon number and molecular weight are important characteristics used by recent models to describe evolution in OM composition, this technique can provide semi-quantitative, observational constraints of these variables at the scale of the network. For this task, multivariate statistical models are trained on calibration spectra prepared from atmospherically relevant laboratory standards and are applied to ambient samples. Then, the physical basis linking the absorbance profile of this relatively narrow region in the mid-infrared spectrum to the molecular structure is investigated using a classification approach. The multivariate statistical models predict mean carbon number and molecular weight that are consistent with previous values of organic-mass-to-organic-carbon (OM/OC) ratios estimated for the network using different approaches. The results are also consistent with temporal and spatial variations in these quantities associated with aging processes, and different source classes (anthropogenic, biogenic, and burning sources). For instance, the models estimate higher mean carbon number for urban samples and smaller, more fragmented molecules for samples in which substantial aging is anticipated.

KARAKTERISASI ABSORBANSI LARUTAN DAN PENDUGAAN DERAJAT SOSOH BERAS BERDASARKAN ABSORBANSI PADA SPEKTRUM ULTRA- VIOLET

<p>Teknologi non-destruktif seperti penggunaan gelombang ultra-violet (UV) dapat dijadikan sebagai alternatif dalam menentukan kualitas beras sosoh. Pengembangan metode pengukuran dan karakterisasi beras sosoh berdasarkan absorbansi spektrumnya pada daerah UV sangat berpotensi dalam evaluasi kualitas beras secara non-destruktif. Penelitian ini bertujuan untuk menganalisis spektrum absorbansi UV pada beberapa varietas beras dengan tingkat penyosohan bervariasi dan menentukan hubungan derajat sosoh beras varietas Ciherang dengan spektrum absorbansi UV dari larutan beras dalam pelarut n-heksana. Larutan beras dibuat dengan pelarut n-heksana dengan perlakuan waktu perendaman dan konsentrasi n-heksana, kemudian dilakukan pengukuran absorbansi larutan pada spektrum UV, dan terakhir dilakukan analisis terhadap absorbansi larutan, dalam hubungannya dengan derajat sosoh. Sebelum analisis absorbansi pada spektrum UV dilakukan, didahului dengan dua pra-pengolahan data yaitu derivatif pertama dan normalisasi. Hasil analisis adalah karakteristik spektra untuk enam varietas beras yang diuji memiliki profil dan pola absorbansi pada spektrum UV dan hubungannya dengan dengan derajat sosoh beras varietas Ciherang adalah dengan nilai koefisien korelasi (r) sebesar 0.927. Dari penelitian ini didapatkan metode persiapan sampel terbaik dengan waktu perendaman 2-3 jam, dan dengan konsentrasi larutan beras dalam pelarut n-heksanasebesar 43.3% absorbansi pada spektrum UV paling besar terjadi pada panjang gelombang 330-335 nm.</p><p> </p><p><strong>Non-destructive technology such as the use of ultra-violet (UV) waves can be used as an alternative in determining the quality of milled rice</strong></p><p>The development of method of measuring and characterizing milled rice based on the absorbance of spectra in the UV area is highly potential in milled rice quality evaluation non-destructively. This study aims to analyze the spectrum of UV absorbance for some rice varieties with varying degree of milling and determining relation degree of milling for ciherang rice varieties with the absorption on UV area of rice solution in n-hexane solvent. The rice solution was prepared with n-hexane solvent by treatment of immersion time and n-hexane concentration, then measured the absorbance of the solution on the UV spectrum, and finally analyzed the absorbance of the solution, in relation to the rice degree of milling. Prior to the analysis of absorbance on the UV spectrum, by two pre-processing data, first derivative and data normalization were performed. The results of the analysis are spectral characteristics for the six rice varieties tested were absorbance profile and pattern on the UV spectrum and its relation with the degree of milling for ciherang rice varieties with the correlation coefficient value (r) of 0.927. It was observed from this research the best sample preparation method was that with 2-3 hours of soaking time, and the concentration of rice solution in 43.3% n-hexane solvent, resulted maximum absorbance on UV spectrum by rice solution at wavelengths of 330-335 nm.</p>

SYNTHESIS AND PRELIMINARY EVALUATION OF 3,3’-DIHYDROXY-4,4’-DIMETHOXYDIBENZYLIDENEACETONE AS SUNSCREEN AND ANTIOXIDANT ACTIVE COMPOUND

Synthesis and preliminary evaluation of 3,3’-dihydroxy-4,4’-dimethoxydibenzylidenacetone (DDB) as sunscreen and antioxidant have been successfully conducted. The compound was prepared throught acid catalyzed condensation reaction between vanillin and aceton using saturated HCl solution in glacial acetic acid. Pre-evaluation of sunscreen active compound candidate was performed by determining electronic absorbance profile, lamdamax, e, lamda c, UVA/UVB ratio, and photostability. While antioxidant activity test was performed using DPPH radical scavenger method. Based on the results obtained, the compound obtained has very good protective effect in UVA regions with high antioxidant activity.

Graphene Quantum Dots-Coated Bismuth Nanoparticles for Improved CT Imaging and Photothermal Performance

By integrating high-performance CT imaging and photothermal therapy (PTT) into one nanoprobe, an effective theranostic can be achieved for clinical cancer treatment. In this study, the graphene quantum dots (GQDs)-coated bismuth (Bi) nanoparticle (NP) as a theranostic nanoprobe is synthesized and its capabilities for computed tomography (CT) imaging and PTT are investigated. Such nanotheranostic exhibits good physiological dispersity with satisfactory blood compatibility and cytotoxicity. Most importantly, the GQDs-Bi NPs offer strong and steady absorbance profile in NIR region with excellent photostability, which can remarkably convert photo-to-thermal with the photothermal efficiency of 30.0%. Thanks to the powerful PTT effect, co-delivery of GQDs-Bi NPs/NIR laser can effectively induce HeLa cells death in vitro. Cooperatively, NPs hold X-ray attenuation coefficient for high-contrast CT imaging with the corresponding CT improvement efficacy as high as 32.7[Formula: see text]HU[Formula: see text]mg[Formula: see text]. The obtained results highlight the potential of GQDs-Bi NPs as a successful theranostic nanoagent for CT imaging and cancer photothermal therapy.

Determination of specific proteins by the FIA principle

The following analytes have been investigated: urine albumin (u-albumin), plasma-transferrin (p-transferrin), p-haptoglobin, p-IgG, p-IgA, p-IgM, and p-orosomucoid. An unmodified commercial analytical system FIA Star (Tecator) with a two-channel injector (40 μl) was used. The prediluted plasma samples and antibodies are allowed to react for 33 s before the change in turbidity is measured as a Peak maximum at 405 nm. The optimal concentrations of calibrators and antibodies have been determined to secure antibody excess. Response time (i.e. delay between aspiration of a sample and presentation of the result in absorption units) is 75 s. Automatic print-out of the absorbance profile and movement of the sample rack further accounted for 21 s per sample, so the throughput is reduced to 75 determinations per 2 h. Results are available within an hour, compared to two-12 days with the present methods (electroimmunoassays). Parallel analyses with established methods/analysers show excellent agreement for u-albumin, p-transferrin and p-haptoglobin. For p-IgG, p-IgA and p-IgM the reaction time of 33 s is insufficient because their relative molecular masses (i.e. the size of the molecules) are so high, 150.000-971.000. Five minutes is a more adequate reaction time, which makes a serial analyser such as FIA Star unsuitable for larger workloads of samples of immunoglobulins. The plasma concentration of Orosomucoid is low, resulting in high sample blanks. It is therefore recommended that the reaction is followed kinetically if a serial analyser is used.