The Folin-Ciocalteu (FC) method is the most common used for total phenolic content (TPC) determination, but in recent years, a more specific that does not detect non-phenolic reducing compounds has been developed, Fast Blue BB (FBBB) assay. In this study, reference spectrophotometric methods have adapted to rising, simple, fast and low-cost technique (Digital Image Analysis, (DIA)) based assay while studying if reaction time of both could be reduced applied determination TPC food samples....

A quantitative method for acid-base titrations in paper-based devices (PADs) is described to analyze acetic acid vinegar samples. In this work, two different types of PADs were developed: a device individual spot testing and microfluidic device. Digital colorimetry was used as the detection method, images acquired using smartphone homemade box with LED lights controlled image acquisition. Titration curves built just eight points, R channel based on gradual color transition from red blue...

A screening method for determination of six triazole fungicides (diniconazole, fluquinconazole, flusilazole, myclobutanil, tebuconazole and tetraconazole) using the solid-phase microextraction (SPME) technique coupled to a high-performance liquid chromatography-diode array detector (HPLC-DAD) was developed. Experimental variables were chosen their values fixed according an experimental design with steps (25−1 fractional factorial design) optimization significant (central composite design)....

The fragmentation mechanisms of prototypical disaccharides have been studied herein by coupling tandem mass spectrometry (MS) with collisional chemical dynamics simulations. These calculations were performed explicitly considering the collisions between protonated sugar and neutral target gas, which led to an ensemble trajectories for each system, from it was possible obtain reaction products without pre-imposing them. β-aminoethyl aminopropyl derivatives cellobiose, maltose, gentiobiose...

Nickel is the most employed metal in electroless coating baths, and its concentration must be continuously well controlled to obtain desired qualities. Nowadays, automated systems for control are used industry, but they expensive unaffordable small companies. Therefore, development of a simplest method that provides rapid results without requiring big amount sample could an improvement these industries. In this study, semiautomatic based on digital image analysis (DIA) presented. A...

The interactions between formamide, which can be considered a prototype of peptide function, and Sr2+ have been investigated by combining nanoelectrospray ionization/mass spectrometry techniques G96LYP DFT calculations. For Sr an extended LANL2DZ basis set was employed, together with 6-311+G(3df,2p) expansion for the remaining atoms system. observed reactivity seems to dominated Coulomb explosion process yielding [SrOH]+ + [HNCH]+, are most intense peaks in MS/MS spectra. Nevertheless,...

The collision induced dissociation of formamide–Ca2+ complexes produced in the gas phase through nanoelectrospray ionization yields as main products ions [CaOH]+, [HCNH]+, [Ca(NH2)]+, HCO+ and [Ca(NH3)]2+ possibly [Ca(H2O)]2+ [C,O,Ca]2+, latter being rather minor. mechanisms behind these fragmentation processes have been established by analyzing topology potential energy surface means B3LYP calculations carried out with a core-correlated cc-pWCVTZ basis set. Ca2+ formed formamide itself...

Abstract Colorants are widely used in food industry to improve appearance of edible products. This work present a method for the determination two colorants, tartrazine and allura red, with UV‐Vis spectrophotometry MCR‐ALS using only five standards calibration correlation constraint. is usually applied second‐order data but it rarely has been first order data, which more usual use PLS. In this case, can show some advantages like interference identification reduced matrix. Using methodology,...

There is evidence that the interaction of α-ketol group Doxorubicin and Epirubicin anti-cancer drugs with Fe(III) generates hydroxyl radicals under aerobic conditions, causing cardiotoxicity in patients. Considering formation DNA adducts one main targets Anthracycline drugs, we have present study characterized several [Anthracycline–DNA]Fe(III) complexes respect to their stability coordination, by means MD simulations. Iron found coordinate well containing an group, this being only drug...

Acrolein occasionally appears in cider, completely spoiling its quality due to bitter taste. It is crucial detect it the early steps, before taste severely affected, apply appropriate treatment. A simple and rapid analytical method determine this compound cider therefore desirable. In work, a quantitative determination of acrolein proposed using proton nuclear magnetic resonance technique (1H NMR). produces doublet signal spectrum at 9.49 ppm, whose area used concentration compound....

The structures and relative stabilities of the complexes formed by uracil its thio- seleno-derivatives with Sr(2+) cation, in gas phase, have been analyzed means G96LYP density functional theory (DFT) calculations. attachment cation to heteroatom at position 4 is preferred systematically. Although enolic forms derivatives should not be observed corresponding are most stable. enhanced stability these tautomers two-fold, on one hand interacts two basic sites simultaneously, other an...

The gas-phase acidity of R--XH (R=H, CH(3), CH(2)CH(3), CH==CH(2), C[triple chemical bond]CH; X=Be, Mg, Ca) alkaline-earth-metal derivatives has been investigated through the use high-level CCSD(T) calculations by using a 6-311+G(3df,2p) basis set. BeH(2) is stronger acid than BH(3) and CH(4) for two concomitant reasons: 1) dissociation energy Be--H bond smaller energies B--H C--H bonds, 2) electron affinity BeH(.) larger in absolute value those BH(2) (.) CH(3) (.). also increases on going...

The interactions between urea and Sr(2+) in the gas phase have been investigated by combining electrospray ionization/mass spectrometry techniques density functional high-level ab initio molecular orbital calculations. Our theoretical survey indicates that [Sr(urea)](2+) adducts are thermodynamically stable with respect to direct Coulomb explosions. However, after isomerization, some of local minima PES unstable formation NH(4)(+), but kinetically metastable. loss neutral fragments...

In this work, a method based on UV–VIS spectrophotometry using the molybdenum blue reaction is described to monitor hypophosphite and phosphite levels in nickel electroless baths. Nickel one of most employed metals coating industry during deposition process metal reduced from Ni (II) (0). Hypophosphite widely reducing agent, which oxidized phosphite. Therefore, concentration should be monitored order replenish bath while it being consumed maintaining an optimum guarantee desired coating....