DETERMINATION OF T.N.T. (2,4,6-TRINITROTOLUENE) IN AIR

1941 ◽  
Vol 19b (3) ◽  
pp. 86-89 ◽  
Author(s):  
Kingsley Kay
Keyword(s):  
Sodium Hydroxide ◽  
Field Tests ◽  
Practical Method ◽  
Optimum Conditions ◽  
Accurate Comparison ◽  
The Stability ◽  
Red Coloration

A practical method for determining the concentration of T.N.T. in workroom atmospheres has been developed and has been given successful field tests. The accuracy of the method described is approximately ± 10%. The method is a comparative one, depending upon the red coloration produced when 2,4,6-trinitrotoluene in acetone is treated with a solution of sodium hydroxide in water. The stability of the coloration has been studied and the optimum conditions of temperature and concentrations of reactants have been determined. In addition the range of colour that allows the most accurate comparison has been evaluated. Minor refinements are at present in progress with a view to increasing the accuracy of the test.

Spectrophotometric Determination of Maleic Hydrazide in Tobaccos

1961 ◽  
Vol 44 (4) ◽  
pp. 723-725
Author(s):  
I Hoffman
Keyword(s):  
Sodium Hydroxide ◽  
Spectrophotometric Determination ◽  
Plant Material ◽  
Maleic Hydrazide ◽  
Sodium Hydroxide Solution ◽  
Important Regulator ◽  
Increased Sensitivity ◽  
The Stability ◽  
Empirical Constants

Abstract Maleic hydrazide (6-hydroxy-3-(2H) pyridazinone) has properties that make it an important regulator for the control of sucker growth in tobacco. The stability and persistence of maleic hydrazide in plants was reviewed by Smith and co-workers (3). Several procedures have been reported for its determination in plant material (1, 2, 4) but these have proved to be unsatisfactory when applied to tobacco. This failure is due primarily to the strong red interfering color which results when tobacco in sodium hydroxide solution is distilled with added zinc. The reported procedures attempt to minimize this interference by the use of empirical constants and absorbance ratio factors. This paper outlines a modified procedure of greatly increased sensitivity which removes the interference entirely, and which is applicable to various types of tobacco tested (flue-cured, cigar, burley, and aromatic)

scholarly journals Continuous low-maintenance CO<sub>2</sub>/CH<sub>4</sub>/H<sub>2</sub>O measurements at the Zotino Tall Tower Observatory (ZOTTO) in Central Siberia

2010 ◽  
Vol 3 (4) ◽  
pp. 1113-1128 ◽  
Author(s):  
J. Winderlich ◽  
H. Chen ◽  
C. Gerbig ◽  
T. Seifert ◽  
O. Kolle ◽  
...  
Keyword(s):  
Water Vapor ◽  
Accurate Determination ◽  
Field Tests ◽  
Central Siberia ◽  
Mixing Ratios ◽  
Air Sample ◽  
The Stability ◽  
Carbon Dioxide Co2 ◽  
Tall Tower

Abstract. To monitor the continental carbon cycle, a fully automated low maintenance measurement system is installed at the Zotino Tall Tower Observatory in Central Siberia (ZOTTO, 60°48' N, 89°21' E) since April 2009. A cavity ring-down spectroscopy (CRDS) analyzer continuously measures carbon dioxide (CO2) and methane (CH4) from six heights up to 301 m a.g.l. Buffer volumes in each air line remove short term CO2 and CH4 mixing ratio fluctuations associated with turbulence, and allow continuous, near-concurrent measurements from all tower levels. Instead of drying the air sample, the simultaneously measured water vapor is used to correct the dilution and pressure-broadening effects for the accurate determination of dry air CO2 and CH4 mixing ratios. The stability of the water vapor correction was demonstrated by repeated laboratory and field tests. The effect of molecular adsorption in the wet air lines was shown to be negligible. The low consumption of four calibration tanks that need recalibration only on decadal timescale further reduces maintenance. The measurement precision (accuracy) of 0.04 ppm (0.09 ppm) for CO2 and 0.3 ppb (1.5 ppb) for CH4 is compliant with the WMO recommendations. The data collected so far (until April 2010) reveals a seasonal cycle amplitude for CO2 of 30.4 ppm at the 301 m level.

scholarly journals Optimum Conditions for Determination of the Stability of Weak Complexes.

1969 ◽  
Vol 23 ◽  
pp. 2808-2814 ◽  
Author(s):  
Gunnar Norheim ◽  
Kjell P. Walseth ◽  
Svend Erik Rasmussen ◽  
D. Heinegård ◽  
Alexandru T. Balaban ◽  
...  
Keyword(s):  
Optimum Conditions ◽  
Weak Complexes ◽  
The Stability

scholarly journals Optimization of Chromium Speciation into Cr(III) - Tannic form

2020 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Jenifer Alfonda Walewangko ◽  
Djefry Tani ◽  
Joice Caroles
Keyword(s):  
Metal Species ◽  
Complexing Agent ◽  
Chromium Speciation ◽  
Optimum Conditions ◽  
Acid Complex ◽  
Chromium Species ◽  
Optimum Ph ◽  
The Stability ◽  
Heavy Metal Species

This research was conducted to determine the heavy metal species of Cr (III). Determination of heavy metals is determined based on the required chromium species using the UV-Vis spectrophotometry method. The sample used was CrCl3.H2O and the complexing agent was tannic acid. This research was conducted to determine the effect of pH, concentration and time of stability by finding the optimum conditions of the chromium - tanic acid complex. The optimum pH is at pH 11, the optimum concentration is at a ratio of 5: 1 concentration (Cr: tanic acid), the stability of time is at the 10th minute.

Sensitive Determination of Sertraline in Commercial Drugs and Its Stability Check in Simulated Gastric Juice

2016 ◽  
Vol 99 (6) ◽  
pp. 1527-1532 ◽  
Author(s):  
Elif Seda Koçoğlu ◽  
Sezgin Bakırdere ◽  
Seyfullah Keyf
Keyword(s):  
Gastric Juice ◽  
Quantitative Measurement ◽  
Calibration Plot ◽  
Optimum Conditions ◽  
Selected Ion Monitoring ◽  
Qualitative And Quantitative ◽  
Lower Detection ◽  
Sensitive Determination ◽  
The Stability

Abstract A sensitive analytical method was developed for the determination of sertraline in commercial drug samples by using GC–MS. The selected-ion monitoring mode was used at the most sensitive m/z 274 to obtain a lower detection limit. LOD/LOQ values were obtained as 1.6/5.4 ng/mL for sertraline under the optimum conditions. The calibration plot was linear between 5.0 and 2000 ng/mL with the correlation coefficient of 0.9999. The validated method was successfully applied to three different brands of drug samples for both qualitative and quantitative measurement of sertraline. In this experiment, four replicate extractions were performed for each brand, and the results were compared to the values written on the labels of the drug brands. Spiking experiments were also performed to check the effect of the matrixes on the determination, and it was observed that there was no shift in the retention time of the analyte. In addition, simulated gastric juice experiments were performed to check the stability of sertraline in the stomach for 240 min, and it was observed that there was no change in the structure of the analyte.

scholarly journals Determination of Trace Amount of Pd(II) and Ni(II) with Newly Synthesized Pyrozlon Azo Bromo Phenol by Spectrophotometric Methods

2011 ◽  
Vol 8 (s1) ◽  
pp. S425-S433 ◽  
Author(s):  
Hussain J Mohammed ◽  
Azhar Y Muhi ◽  
Hayder Al Meisslemaw
Keyword(s):  
Linear Correlation ◽  
Conductivity Measurements ◽  
Optimum Conditions ◽  
Selective Method ◽  
Spectrophotometric Methods ◽  
Full Color ◽  
Color Development ◽  
The Stability ◽  
Intense Color

A sensitive and selective method has been developed for the determination of palladium(II) and nickel(II). A new reagent and two complexes have been prepared in aqueous solutions. The method is based on the chelation of metal ions with 4-(4'- antipyriyl azo ) -2-bromo phenol (APBP) to form an intense color soluble products, that are stable and have a maximum absorption at 498 nm and at 433.5 nm and εmaxof 0.21×104and.0.38×104Lmole-1cm-1for Pd(II) Ni(II) respectively. A linear correlation of (0.2 - 3) and (0.6 -2.2) ppm for Pd(II) Ni(II) respectively. The stoichiometry of both complexes was found to be 1:2 (metal:ligand). The effect of various cations and anions on Pd(II) and Ni(II) determination have been investigated. The stability constants Pd(II) and Ni(II) were 0.37×108, 0.38×108L mol-1respectively. The conductivity measurements for complexes are consistent with those expected for an electrolyte. The optimum conditions for full color development for described methods were applied satisfactorily to synthetic mixtures samples and biological samples.

Spectrophotometric determination of nickel(II) in different samples by complexation with some triazolylazo dyes

2006 ◽  
Vol 60 (2) ◽  
Author(s):  
A. Khedr
Keyword(s):  
Spectrophotometric Determination ◽  
Aqueous Media ◽  
Direct Determination ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Phenolic Ring ◽  
Determination Of Nickel ◽  
The Stability ◽  
Sensitive Spectrophotometric Method

AbstractA new sensitive spectrophotometric method for the determination of nickel(II) with 3-(2-hydroxy-5-acetyl-(L1),-5-ethoxycarbonyl-(L2),-5-methyl-(L3),-5-formyl-(L4),-5-bromophen-1-ylazo)-1,2,4-triazole (L5), and 3-(2,4-dihydroxyphen-1-ylazo)-1,2,4-triazole (L6) in aqueous media containing 40 vol. % methanol has been developed. The method is based on the formation of stable coloured Ni(II) complexes with stoichiometric ratios 1: 1 and 1: 2 (n(M): n(L)). Linear calibration graphs are obtained up to 7.04 µg cm−3 of nickel(II) under optimum conditions attained from investigation of complex formation. The absorption maxima varied from 485 nm to 545 nm and the molar absorptivities ranged from 0.84 × 104 to 4.65 × 104 dm3 mol−1 cm−1 for 1: 1 and 1: 2 (n(M): n(L)) complexes with varying the substituent on the phenolic ring. The optimum ranges for the direct determination of nickel(II) (Ringbom) and the stability constants of the formed complexes are determined. The developed method was applied to the spectrophotometric determination of nickel(II) in some samples with satisfactory results.

Simultaneous Spectrophotometric Determination of Salbutamol by Coupling with Diazotized 4-Aminobenzoic acid

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Hind Hadi ◽  
Gufran Salim
Keyword(s):  
Pharmaceutical Preparations ◽  
Coupling Reaction ◽  
Dosage Forms ◽  
Water Soluble ◽  
Trace Determination ◽  
Aminobenzoic Acid ◽  
Optimum Conditions ◽  
Colored Product ◽  
Versus Concentration

A simple, rapid and sensitive spectrophotmetric method for trace determination of salbutamol (SAL) in aqueous solution and in pharmaceutical preparations is described. The method is based on the diazotization coupling reaction of the intended compound with 4-amino benzoic acid (ABA) in alkaline medium to form an intense orange, water soluble dye that is stable and shows maximum absorption at 410 nm. A graph of absorbance versus concentration indicates that Beer’s law is obeyed over the concentration range of 0.5-30 ppm, with a molar absorbtivity 3.76×104 L.mol-1 .cm-1 depending on the concentration of SAL. The optimum conditions and stability of the colored product have been investigated and the method was applied successfully to the determination of SAL in dosage forms.

Spectrophotometeric Determination of Trifluoperazine HCL in Pure Forms and Pharmaceutical Preperations

2017 ◽  
Vol 9 (5) ◽  
Author(s):  
Mohammad Hamzah Hamzah ◽  
Rawa M M Taqi ◽  
Muna M. Hasan ◽  
Raid J. M. Al-Timimi
Keyword(s):  
Standard Method ◽  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Oxidizing Agent ◽  
Optimum Conditions ◽  
Limit Of Quantification ◽  
Cerium Ion ◽  
Blank Solution

A simple and accurate spectrophotometric method for the determination of Trifluoperazine HCl in pure and dosage forms was developed. The method is based on the reaction between Trifluoperazine HCl and p-chloroaniline in the presence of cerium ion as oxidizing agent which lead to the formation of violate color product that absorbed at a maximum wavelength 570nm while the blank solution was pink. Under the optimum conditions a linear relationship between the intensity and concentration of TRF in the range 4-50μg/ml was obtained . The molar absorptivity 3.74×103 L.mol-1.cm-1 , Limit of detection (2.21μg/ml), while limit of quantification was 7.39μg/ml. The proposed analytical method was compared with standard method using t-test and F-test , the obtained results shows there is no significant differences between proposed method and standard method. Based on that the proposed method can be used as an alternative method for the determination of TRF in pure and dosage forms.

Sign in / Sign up

Export Citation Format

Share Document