Determination of the root canal length using impedance ratio method

Author(s):  
Dejan Krizaj ◽  
J. Jan ◽  
T. Žagar
Author(s):  
RUAA MUAYAD MAHMOOD ◽  
HAMSA MUNAM YASSEN ◽  
SAMAR , NAJWA ISSAC ABDULLA AHMED DARWEESH ◽  
NAJWA ISSAC ABDULLA

Simple, rapid and sensitive extractive spectrophotometric method is presented for the determination of glibenclamide (Glb) based on the formation of ion-pair complex between the Glb and anionic dye, methyl orange (MO) at pH 4. The yellow colored complex formed was quantitatively extracted into dichloromethane and measured at 426 nm. The colored product obeyed Beer’s law in the concentration range of (0.5-40) μg.ml-1. The value of molar absorptivity obtained from Beer’s data was found to be 31122 L.mol-1.cm-1, Sandell’s sensitivity value was calculated to be 0.0159 μg.cm-2, while the limits of detection (LOD) and quantification (LOQ) were found to be 0.1086 and 0.3292 μg.ml-1, respectively. The stoichiometry of the complex created between the Glb and MO was 1:1 as determined via Job’s method of continuous variation and mole ratio method. The method was successfully applied for the analysis of pharmaceutical formulation.


Author(s):  
Nesma M Fahmy ◽  
Adel M Michael

Abstract Background Modern built-in spectrophotometer software supporting mathematical processes provided a solution for increasing selectivity for multicomponent mixtures. Objective Simultaneous spectrophotometric determination of the three naturally occurring antioxidants—rutin(RUT), hesperidin(HES), and ascorbic acid(ASC)—in bulk forms and combined pharmaceutical formulation. Method This was achieved by factorized zero order method (FZM), factorized derivative method (FD1M), and factorized derivative ratio method (FDRM), coupled with spectrum subtraction(SS). Results Mathematical filtration techniques allowed each component to be obtained separately in either its zero, first, or derivative ratio form, allowing the resolution of spectra typical to the pure components present in Vitamin C Forte® tablets. The proposed methods were applied over a concentration range of 2–50, 2–30, and 10–100 µg/mL for RUT, HES, and ASC, respectively. Conclusions Recent methods for the analysis of binary mixtures, FZM and FD1M, were successfully applied for the analysis of ternary mixtures and compared to the novel FDRM. All were revealed to be specific and sensitive with successful application on pharmaceutical formulations. Validation parameters were evaluated in accordance with the International Conference on Harmonization guidelines. Statistical results were satisfactory, revealing no significant difference regarding accuracy and precision. Highlights Factorized methods enabled the resolution of spectra identical to those of pure drugs present in mixtures. Overlapped spectra of ternary mixtures could be resolved by spectrum subtraction coupled FDRM (SS-FDRM) or by successive application of FZM and FD1M.


1972 ◽  
Vol 26 (1) ◽  
pp. 96-99 ◽  
Author(s):  
Mary Jo Calhoun ◽  
Edward S. DellaMonica

A method for the determination of individual components of complex mixtures is presented. The technique used is based on ir-absorbance measurements for stearic acid at 1700 and at 935 cm−1 when the concentration range exceeds 0.50% wt/vol; for isopropenyl stearate at 1145 and at 865 cm−1; for stearic anhydride at 1030 cm−1 and mixed stearic-acetic anhydride at 1000 cm−1. The baseline method was used in all absorbance measurements. Absorbance-concentration relationships obeyed Beer's law from 0 to 2.0% wt/vol for most compounds; the exception being stearic acid (at 1700 cm−1), where linearity was limited to a maximum 0.50% wt/vol. Due to spectral interference between the two anhydrides at low concentration ratios, an empirical percent transmission ratio method was used to estimate the relative concentration of each. Binary and ternary systems were studied and the standard deviations of the differences between theoretical and calculated values indicate that this method is reliable.


2002 ◽  
Vol 35 (7) ◽  
pp. 590-593 ◽  
Author(s):  
F. Grimberg ◽  
G. Banegas ◽  
L. Chiacchio ◽  
O. Zmener

Agromet ◽  
2018 ◽  
Vol 32 (1) ◽  
pp. 11
Author(s):  
Tania June ◽  
Ni Wayan Srimani Puspa Dewi ◽  
Ana Meijide

<p>Oil palm is one important agricultural commodity that has high economic value. Oil palm productivity is significantly influenced by its water use (needs). Measurement and estimation of oil palm evapotranspiration is needed for determination of its water needs. Various methods are available and this study compare three methods, consisting of aerodynamic, Bowen-Ratio and Penman-Monteith methods in analyzing water needs/use of oil palms plantation located in PTPN VI Jambi.  Peak of evapotranspiration rate occured in the afternoon around 13.00 and 14.00 local time. Bowen-Ratio method has higher estimation value of evapotranspiration than the other two methods. Ratio between evapotranspiration and global radiation of two and ten-years old oil palm plantations remain similar, around 47%. Penman Monteith method has the nearest estimation value to reference method (aerodynamic method) showed by the smallest RMSE value, 0.087 for two years oil palm and 0.157 for ten-years old oil palm.<strong> </strong></p>


2019 ◽  
Vol 3 (1) ◽  
pp. 1-5
Author(s):  
Parichehr Pourshakibaei ◽  
Mohammad Taghi Mashkouri Najafi ◽  
Amir Hossein Akbari Zahmati ◽  
Mehrnoush Afiat ◽  
Masoumeh Vaghari ◽  
...  

1999 ◽  
Vol 82 (3) ◽  
pp. 683-688 ◽  
Author(s):  
Zorana Grabaric ◽  
Ljerka Bokic ◽  
Branka Stefanovic

Abstract The Schiff base 2-(2-pyridylmethyieneamino)phenol (PMAP) was investigated as a spectrophotometric reagent for determination of iron in caustic soda, cotton yarn and fabric, woolen fabric, and industrial water. The solution properties of Fe(III)-PMAP complexes were determined. At pH 4.4 and 5.6, Fe(III) forms stable complexes with PMAP, with molar absorption coefficients (ε) of 3.00 × 103 and 7.44 × 103/M.cm, respectively. Composition and cumulative stability constants were determined by the mole ratio method (MRM) and the mole fraction variation method (MFVM). At the lower pH (4.4), the predominant complex species in the solution obtained with both methods are ML2, with fairly good agreement of stability constants: log βML2 = 7.00 ± 0.04 with MRM and 7.31 ± 0.01 with MFVM. At the higher pH (5.6), the composition and stability constants of predominant complex species in the solution obtained with the 2 methods were not in good agreement, perhaps because of the coexistence of several species, such as Fe-PMAP, Fe-hydroxo, and Fe-acetate complexes. PMAP is a sensitive reagent for determination of Fe(III). The detection limit of 0.4 μg/mL is lower than those of other frequently used spectrophotometric reagents for Fe. The reagent is ecologically more acceptable, because extraction with organic solvents is avoided. All measurements were made at pH 5.6 because sensitivity was higher at this pH. The high Fe values obtained for industrial water (31.8 μg/mL) indicate that some modifications in the process have to be done. Concentration of Fe in wastewater was much lower (15.9 μg/mL). The results for cotton and woolen fabric indicate that accumulation of Fe in wool is much higher than in cotton (84.4 μg/mL and 29.3-53.1 μg/mL, respectively).


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