Spectrophotometric Method for Microdetermination of Nitrogen in Kjeldahl Digest

1989 ◽  
Vol 72 (6) ◽  
pp. 953-956 ◽  
Author(s):  
Muljibhai B Devani ◽  
Chamanlal J Shishoo ◽  
Shailesh A Shah ◽  
Bhanubhai N Suhagia
Keyword(s):  
Standard Deviation ◽  
Nitrogen Content ◽  
Spectrophotometric Method ◽  
Acidic Medium ◽  
Molar Absorptivity ◽  
Nitrogen Compounds ◽  
Relative Standard ◽  
Kjeldahl Method ◽  
Aoac Method

Abstract A new spectrophotometric method for the determination of nitrogen in Kjeldahl digest has been developed. The method is based on the reaction of ammonia with acetylacetone-formaldehyde reagent in aqueous medium to yield yellow 3,5-diacetyl- 1,4-dihydrolutidine with a characteristic absorption maxima at 412 nm. The effect of several experimental variables on the determination of nitrogen was studied. The method was suitable for determination of nitrogen in acidic medium without interference from the usual catalysts employed for the digestion in Kjeldahl method. Lambert-Beer’s law is obeyed in the concentration range of 0.5-6.0 ng nitrogen/mL in the reaction mixture. The molar absorptivity in terms of nitrogen was 1.4 X 103L mol-1 cm-1. The standard deviation and relative standard deviation were ±0.0447 and ±0.896% (n = 10), respectively. The method is simple, rapid, and precise. A variety of carbocyclic and heterocyclic nitrogen compounds have been analyzed for nitrogen content. The results are comparable with those obtained by AOAC method, 47.021.

scholarly journals Development and validation of spectrophotometric method for phenylephrine hydrochloride estimation in nasal drops formulations

2008 ◽  
Vol 27 (2) ◽  
pp. 149 ◽  
Author(s):  
Ivana Savić ◽  
Goran Nikolić ◽  
Vladimir Banković
Keyword(s):  
Standard Deviation ◽  
Sodium Hydroxide ◽  
Relative Standard Deviation ◽  
Spectrophotometric Method ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Phenylephrine Hydrochloride ◽  
Relative Standard ◽  
Development And Validation

Simple, accurate and reproducible UV-spectrophotometric method was developed and validated for the estimation of phenylephrine hydrochloride in pharmaceutical nasal drops formulations. Phenylephrine hydrochloride was estimated at 291 nm in 1 mol⋅dm-3 sodium hydroxide (pH 13.5). Beer’s law was obeyed in the concentration range of 10–100 μg⋅cm−3 (r2 = 0.9990) in the sodium hydroxide medium. The apparent molar absorptivity was found to be 1.63×103 dm3⋅mol−1⋅cm−1. The method was tested and validated for various parameters according to the ICH (International Conference on Harmonization) guidelines. The detection and quantitation limits were found to be 0.892 and 2.969 μg⋅cm−3, respectively. The proposed method was successfully applied for the determination of phenylephrine hydrochloride in pharmaceutical nasal drops formulations. The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation < 1 %), while being simple, cheap and less time consuming, and hence can be suitably applied for the estimation of phenylephrine hydrochloride in different dosage forms.

scholarly journals Spectrophotometric Method for Determination of Paraquat in Food and Biological Samples

1997 ◽  
Vol 80 (2) ◽  
pp. 388-391 ◽  
Author(s):  
Ritu Kesari ◽  
Manish Rai ◽  
Vinay Kumar Gupta
Keyword(s):  
Standard Deviation ◽  
Metal Ions ◽  
Relative Standard Deviation ◽  
Alkaline Medium ◽  
Spectrophotometric Method ◽  
Biological Samples ◽  
Molar Absorptivity ◽  
Relative Standard ◽  
Sensitive Spectrophotometric Method

Abstract A sensitive spectrophotometric method was developed for determination of paraquat, a widely used herbicide. Paraquat was reduced with glucose in an alkaline medium, and the blue radical ion obtained was measured at 600 nm. Beer’s law was obeyed at 0.1–1.2 ppm paraquat. The molar absorptivity was 1.26 × 105 L mol-1 cm-1. The standard deviation and relative standard deviation were ± 0.007 and 2.0%, respectively, for 5 μg paraquat/10 mL analyzed over 7 days. The method was free from interference by other commonly used pesticides and metal ions. The method may be used to the determine paraquat in plants, fruits, grains, water, blood, and urine.

scholarly journals Flotation-Spectrophotometric Method for the Determination of Aluminium ion Using Xylenol Orange

2011 ◽  
Vol 8 (4) ◽  
pp. 1528-1535 ◽  
Author(s):  
F. Nekouei ◽  
Sh. Nekouei
Keyword(s):  
Standard Deviation ◽  
Spectrophotometric Method ◽  
Calibration Curve ◽  
Limit Of Detection ◽  
Xylenol Orange ◽  
Molar Absorptivity ◽  
Relative Standard ◽  
Ion Associate ◽  
Sensitive Method

A simple, fast, reproducible and sensitive method for the flotation- spectrophotometric determination of Al3+is reported. The apparent molar absorptivity (ε) of the ion associate was determined to be 8.35×104L mol-1cm-1. The calibration curve was linear in the concentration range of 1.0-50 ng mL-1of Al3+with a correlation coefficient of 0.9997. The limit of detection (LOD) was 0.621 ng mL. The relative standard deviation (RSD) at 10 and 30 ng mL-1of aluminium were 1.580 and 2.410% (n=7) respectively. The method was applied for measuring the amount of aluminium in water samples.

Spectrophotometric Determination of Boron in Dates of Some Cultivars Grown in Saudi Arabia

1993 ◽  
Vol 76 (3) ◽  
pp. 601-603 ◽  
Author(s):  
A A Al-Warthan ◽  
S S Al-Showiman ◽  
S A Al-Tamrah ◽  
A A BaOsman
Keyword(s):  
Saudi Arabia ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Molar Absorptivity ◽  
Relative Standard ◽  
Sensitive Spectrophotometric Method

Abstract The formation of a red complex between boron and the quinalizarin reagent was investigated and used as the basis for a simple and sensitive spectrophotometric method for boron in date cultivars. At 620 nm, the absorbance was linear (r= 0.999) over the 0.25-2.5 μg/mL concentration range. The molar absorptivity was found to be 2.23 x 103mol-1cm-1 and the relative standard deviation for 10 replicates (1.0 μg/mL) was 0.97%.

Flotation-Dissolution-Spectrophotometric Determination of Phorate in Various Environmental Samples

2020 ◽  
Vol 33 (1) ◽  
pp. 18-23
Author(s):  
Harshita Sharma ◽  
Anushree Saha ◽  
Chhaya Bhatt ◽  
Kalpana Wani ◽  
Ajay Kumar Sahu ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Spectrophotometric Determination ◽  
Acidic Medium ◽  
Molar Absorptivity ◽  
Ammonium Molybdate ◽  
Organophosphate Pesticide ◽  
Organic Layers ◽  
Relative Standard ◽  
Ion Associate

The proposed method is based on flotation–dissolution an easy, impressible, extractive spectrophotometric determination, explained for easy investigation of the organophosphate pesticide phorate (O,O-diethyl S-[ethylthiomethyl] phosphorodithioate) on trace levels. A molybdophospho complex is generated when prorate is treated with ammonium molybdate in acidic medium. As an ion associate complex with methylene blue the complex is present in between of the water and organic layers which is extracted and then dissolved with acetone. The greenish blue complex produced show absorption maxima at 660 nm. Beer’s law range is found to be 0.5 to 16 µg per 10 ml for phorate. The molar absorptivity is 0.989×103 L mol-1 cm-1 and sandell’s sensitivity is 1.00×10-5 µg cm-2. Also calculated the standard deviation and relative standard deviation for the above method were ±0.006 and 1.95% respectively. The method has been applied and checked for the determination of phorate in water, soil and vegetables.

scholarly journals Spectrophotometric Method for the Determination of Paracetamol

1970 ◽  
Vol 24 ◽  
pp. 39-44 ◽  
Author(s):  
Buddha Ratna Shrestha ◽  
Raja Ram Pradhananga
Keyword(s):  
Standard Deviation ◽  
Spectrophotometric Method ◽  
Trace Amount ◽  
Pharmaceutical Preparation ◽  
Chemical Society ◽  
Molar Absorptivity ◽  
Coupling Agents ◽  
Clinical Samples ◽  
Relative Standard

Paracetamol with 1-napthol or resorcinol gave azodye and the concentration of paracetamol was investigated spectrophotometrically. The azodyes formed with both 1-napthol and resorcinol as coupling agents follow Lambert Beer's law in the range of 0 to 10 µgmL-1 of paracetamol. The molar absorptivity and Sandell's sensitivity for azodye coupled with 1-napthol were found to be 1.68×104 Lmol-1cm-1 and 9.0 ngmL-1cm-2, respectively. The molar absorptivity and Sandell's sensitivity for azodye coupled with resorcinol were found to be 2.86×104 Lmol-1cm-1 and 5.3 ngmL-1cm-2, respectively. Both coupling agents had been applied successfully in the analysis of paracetamol in pharmaceutical preparation. The relative standard deviation for all five samples ranged from 2.2-6.4% at 95% confidence. The percentage recoveries were found to range from 97.8 to 103.4. Both methods used in the present study may be applied to the determination of trace amount of paracetamol in different clinical samples. Keyword: Paracetamol; Spectrophotometric; 1-napthol; Resorcinol DOI: 10.3126/jncs.v24i0.2389 Journal of Nepal Chemical Society Vol. 24, 2009 Page: 39-44

scholarly journals A New Spectrophotometric Method for Hydrogen Sulphide Through Electrolytically Generated Mn(III) WithO-Tolidine

2008 ◽  
Vol 5 (1) ◽  
pp. 93-99 ◽  
Author(s):  
M. S. Suresha ◽  
Mansour S. Abdul Galil ◽  
Mahadevaiah ◽  
M. A. Sathish ◽  
M. S. Yogendra Kumar ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Hydrogen Sulphide ◽  
Spectrophotometric Method ◽  
Water Samples ◽  
Molar Absorptivity ◽  
Official Method ◽  
Color Intensity ◽  
Orange Yellow ◽  
Relative Standard

A simple, sensitive and economical spectrophotometric method for the determination of hydrogen sulphide is developed. The method is based on a redox reaction in that Mn(III) generated electrolytically is taken in excess, which is oxidizing a known but a less quantity of hydrogen sulphide and the unreacted oxidant will oxidize furthero-tolidine to produce an orange yellow quinonediimine absorbing cation (λ max. 455 nm). Therefore, in principle, the decrease in color intensity of the absorbing system is proportional to the concentration of hydrogen sulphide. The stoichiometry between Mn(III) ando-tolidine and stability constant of the complex were determined by Job's continuous method, the corresponding values were found to be 2:1 and 1.42X105Lmol-1. The system was obeying Lambert-Beer's law in the range 0.2-1.4 μg mL-1of hydrogen sulphide. Molar absorptivity, correlation coefficient and Sandell's sensitivity values were also calculated and found to be 4.2062X103L mol-1cm-1, 0.999 and 0.0012 μg cm-2respectively. The method was employed for the determination of hydrogen sulphide in water samples. The results obtained were reproducible with acceptable standard deviation 0.01-0.068 and relative standard deviation, less than 3.21%. For a comparison, hydrogen sulphide present in water samples were also determined separately following the methylene blue official method. The results of the proposed method compare well with the official method.

scholarly journals Extractive Spectrophotometric Method for Determination of Molybdenum in Steels and Environmental Samples

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Rameshwar Dass ◽  
Jitander K. Kapoor ◽  
Sunita Gambhir
Keyword(s):  
Ascorbic Acid ◽  
Standard Deviation ◽  
Spectrophotometric Method ◽  
Environmental Samples ◽  
Room Temperature ◽  
Molar Absorptivity ◽  
Accuracy And Precision ◽  
Relative Standard ◽  
Improved Accuracy

An extractive spectrophotometric method has been developed for microdetermination of molybdenum. At room temperature Mo(VI) was reduced to Mo(V) in 2 M H2SO4using ascorbic acid as a reductant. The Mo(V) formed a yellow-coloured (1 : 2) complex with 6-chloro-3-hydroxy-2-(3′-hydroxyphenyl)-4-oxo-4H-1-benzopyran (CHHB). The complex was quantitatively extracted into toluene and absorbed maximum atλmax404 nm. Beer’s law was obeyed over the concentration range of 2.31 μg Mo ml−1with a molar absorptivity and Sandell's sensitivity of5.62×104 L mol−1 cm−1and 0.0016 μg Mo cm−2, respectively. The relative standard deviation was 0.0025 (in absorbance units) for 10 replicate determinations of 1 μg Mo ml−1. The method was free from the interference of large number of analytically important elements. Molybdenum has been determined satisfactorily in different technical, synthetic, and environmental samples with improved accuracy and precision.

A Spectrophotometric Determination of Myclobutanil and it’s Applications

2019 ◽  
Vol 31 (1) ◽  
pp. 27-31
Author(s):  
Ajay kumar Sahu ◽  
Shraddha Ganesh Pandey ◽  
Vindhya Patel ◽  
Raisa Khatoon ◽  
Mamta Nirmal ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Spectrophotometric Method ◽  
Molar Absorptivity ◽  
Food Samples ◽  
Final Solution ◽  
Potassium Iodate ◽  
Colored Complex ◽  
Relative Standard ◽  
Solution Volume

A new spectrophotometric method has been developed for determination of fungicide myclobutanil is based on the bromination of myclobutanil to form dibromo myclobutanil which react with Potassium iodide-Potassium iodate mixture in the presence of leucocrystal voilet (LCV) to form a violet colored complex. The complex shows maximum absorbance at 590 nm. Beer’s law obeyed over the concentration range of 0.5-4.0 µg in final solution volume of 10 mL. The reproducibility assessed by carrying out seven days replicate analysis of a solution containing 10 µg of myclobutanil in a final solution of 10 mL. The molar absorptivity of the coloured system is 1.29×105 L mol-1cm-1 and Sandell’s sensitivity is 1.03×10-3 µg cm-2. The standard deviation and relative standard deviation for the absorbance value were found to be ±0.00652 and 1.14% respectively. The proposed method is free from the interference of other toxicants. The analytical parameters were optimized and the method was applied to the determination of myclobutanil in water, soil and food samples.

scholarly journals Determination of the Total Nitrogen Content of Hard, Semihard, and Processed Cheese by the Kjeldahl Method: Collaborative Study

2002 ◽  
Vol 85 (2) ◽  
pp. 445-455 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming ◽  
◽  
◽  
...  
Keyword(s):  
Standard Deviation ◽  
Nitrogen Content ◽  
Relative Standard Deviation ◽  
Total Nitrogen ◽  
Crude Protein ◽  
Collaborative Study ◽  
Processed Cheese ◽  
Relative Standard ◽  
Aoac Method

Abstract The objective of this collaborative study was to determine interlaboratory performance statistics for a modified and optimized version of AOAC Method 920.123 for the determination of the total nitrogen content of hard, semihard, and processed cheese by Kjeldahl analysis. Details included addressing the issues of material homogeneity, test portion size (1 g), quantitative transfer (weighing on to filter paper), ensuring system suitability (nitrogen recoveries), and using AOAC Method 991.20 as the basis for nitrogen analysis. Fifteen laboratories tested 18 pairs of blind duplicate cheese materials with a crude protein content between 18 and 36%. Materials represented hard, semihard, and processed commercial cheeses with a wide range of composition. Statistical performance parameters expressed as crude protein (nitrogen × 6.38), g/100 g, with invalid and outlier data removed were mean = 26.461, repeatability standard deviation (Sr) = 0.111, reproducibility standard deviation (SR) = 0.153, repeatability relative standard deviation (RSDr) = 0.42%, reproducibility relative standard deviation (RSDR) = 0.58%, repeatability (r) = 0.312, and reproducibility (R) = 0.428. The interlaboratory study results were acceptable and comparable to those for the milk Kjeldahl nitrogen method on a relative nitrogen basis. The Study Directors recommend that this modified method for the determination of total nitrogen in hard, semihard, and processed cheese by Kjeldahl analysis be adopted First Action as an improved method to replace Method 920.123.

Sign in / Sign up

Export Citation Format

Share Document