Combining ability of white corn genotypes with two commercial hybrids

White corn is a special type of corn used to make «canjica», a dish appreciated in many regions in Brazil. However, there is a shortage of scientific information, genetic statistical estimates for breeding programs and white corn cultivars for producers to produce grits. The objectives of the present study were to assess two groups of white corn genotypes in a partial diallel cross for the main agronomic traits, estimate the combining ability of the parents and identify promising white corn hybrids for yield and grits quality. The fourteen topcross hybrids obtained from a partial Diallel (2 x 7), using seven genotypes and two commercial testers of the white maize (IPR 119 e IPR 127). The resulting hybrids and the two commercial controls were assessed in the 2011/2012 in the experimental center Agronomic Institute in Campinas (IAC) in growing season at the in Campinas and Tatuí, São Paulo state, Brazil. A randomized block design was used with four replications. The traits assessed were male flowering (MF), female flowering (FF), plant height (PH), ear height (EH), percentage of broken and lodged plants (Ld + Br) and grain yield (GY). There were two treatments for all the traits assessed in the two locations and some hybrids presented higher mean production than the commercial controls. The P7, P1, P3, and P2 genotypes presented the best general com¬bining ability for all the traits assessed. The best estimates for specific combining ability were observed in the P6 x P9, P2 x P9, and P7 x P8 hybrids, indicating dominant loci systems in the genetic control of the traits PH, EH and GY

Linear relationship between potential and concentration in flow potentiometry

In potentiometric-flow systems, linear-potential responses for logarithmic concentrations can be attained for first-(or pseudo-first-) order reactions in which the monitored chemical species react with the analyte during a fixed time interval. To demonstrate this property, the determination of glycerol based on its oxidation by periodate and potentiometric monitoring of the remaining periodate was selected. Influence of reagent concentration and timing on the linearity of the analytical curve were investigated. A mathematical treatment was derived, and potentialities/limitations of the approach were outlined. The system was applied to analysis of soap and lixivia samples. The analytical curve within 200 and 2000 mg L-1 (r = 0.99975; n = 5) was described as E = 8.166 + 0.0478 (glycerol). The sample throughput was 100 h(-1), and a measurement repeatability within 0.5 mV was always observed. By applying a t-test, there was no statistical difference between the results obtained by the proposed procedure and by iodimetric titration at the 95% confidence level. (C) 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:41-45, 2000

Spectrophotometric determination of total nitrogen in plant materials using a flow-injection system with an AgCl(s) reactor

An improved flow-injection system with an AgCl(s) reactor is proposed for the spectrophotometric determination of total nitrogen in Kjeldahl digests of plant materials. After sample injection, the established sample plug is alkalinised and allowed to flow through the mini-column where Ag+ ions are displaced as the soluble [Ag(NH3)(2)](+) complex. Bromopyrogallol red and o-phenanthroline are then added and a coloured ternary complex is formed under neutral conditions. the system is very stable, and baseline drift is usually 0.999 (n=6) and detection limit is 0.2% (w/w) N. Accuracy was confirmed by running standard reference materials and typical samples already assayed by conductimetry. (C) 2000 Elsevier Science B.V. All rights reserved.Universidade Federal de São Paulo, Ctr Energia Nucl Agr, BR-13400970 Piracicaba, SP, BrazilUniversidade Federal de São Paulo, Ctr Energia Nucl Agr, BR-13400970 Piracicaba, SP, BrazilWeb of Scienc

Simultaneous spectrofluorimetric determination of paracetamol and caffeine in pharmaceutical preparations in solid-phase using partial least squares multivariate calibration

Partial least-squares algorithm (PLS)-1 was used for the solid-phase spectrofluorimetric determination of paracetamol (PA) and caffeine (CF) in pharmaceutical formulations. In despite of the closely overlapping spectral bands, the method allows the simultaneous quantification and sample preparation prior to analysis is not required. The calibration set consisted of 96 samples with 100-400 mg/g(-1) PA plus 10-65 mg/g(-1) CF; another set of 25 samples was used for external validation. Agreement between predicted and experimental concentrations was fair (r=0.993 and 0.964 for PA and CF models). Prediction performance was evaluated in terms of the coefficient of variability (CV), relative predictive determination (RPD), and ratio error range (RER). The PLS-1 model was used for the determination of PA and CF in pharmaceutical formulations.39234936

Solid-phase fluorescence spectroscopy for the determination of acetylsalicylic acid in powdered pharmaceutical samples

A rapid, simple and rugged procedure without requiring any prior sample treatment was developed for the determination of acetylsalicylic acid (ASA) in tablets formulations by solid-phase fluorescence spectroscopy. The method was carried out on powdered samples, consisting of an active substance dispersed in lactose, maize starch, talc and magnesium stearate. Previous knowledge of the sample bulk composition is needed for proper application of the method. Wavelengths for maximum excitation and emission were 288 and 318 nm, respectively, and the fluorescence intensity was linear with ASA concentration within the 50-170 mg g(-1) range. Detection and quantification limits were 2.2 and 7.3 mg g(-1), and the analytical frequency was 200 h(-1). For a typical sample, the relative standard deviation of results was estimated as 2.3% (n = 10). Accuracy was assessed by comparing the analytical results obtained with the proposed method with those related to a reference method recommended by British Pharmacopoeia: no differences between the methods were found at the 95% confidence level. (C) 2004 Elsevier B.V. All rights reserved.5231495

Solid-phase spectrofluorimetric determination of acetylsalicylic acid and caffeine in pharmaceutical preparations using partial least-squares multivariate calibration

PLS-1, a variant of the partial least-squares algorithm was used for the solid-phase spectrofluorimetric determination of acetylsalicylic acid (ASA) and caffeine (CF) in pharmaceutical formulations. The method allows the simultaneous quantification of the analytes, as the closely overlapping spectral bands are efficiently solved. Sample preparation prior to analysis is not required. The calibration set consisted of 83 samples with 50-170 mg(-1) ASA plus 5-20 mg g(-1) CF; another set of 25 samples was used for external validation. Agreement between predicted and experimental concentrations was fair (r = 0.987 and 0.974 for ASA and CF models). For both models, the prediction performance was evaluated in terms of the coefficient of variability (CV), relative predictive determination (RPD), and ratio error range (RER). The final PLS-1 models were used for the determination of ASA and CF in pharmaceutical formulations. (C) 2005 Elsevier B.V. All rights reserved.671656