scholarly journals A SIMPLE GREEN REDUCTION STRATEGY TO SUBSTITUTE CADMIUM IN ANALYTICAL REDUCTION OF NITRATE IN GRIESS–ILOSVAY METHOD

Química Nova ◽  
2020 ◽  
Author(s):  
Alexsandro Matias ◽  
André Oliveira ◽  
Antônio Neves ◽  
Maria Eliana Lopes Ribeiro de Queiroz
Keyword(s):  
Standard Deviation ◽  
Mineral Water ◽  
Copper Film ◽  
Coefficient Of Determination ◽  
Reduction Strategy ◽  
Metallic Cadmium ◽  
Doehlert Matrix ◽  
Analytical Range ◽  
Detection And Quantification

Nitrate is an abundant ion that is present in many industrialized products and the environment. Various analytical methods have been described using the Griess-Ilosvay reagent for the determination of nitrate in different matrices after its reduction to nitrite, in most cases with metallic cadmium as the reducer. This work proposes a new method using aluminum spheres coated with a copper film for this reduction. To optimize the method, it was important to evaluate the conditions for the deposition of the copper film on the aluminum spheres, using a Doehlert matrix. The optimized method provided an analytical range from 2.0 to 100 μmol L-1, with a coefficient of determination of 0.9996 and a standard deviation of residuals (sres) of 7.59 x 10-4. The Limits of Detection and Quantification were 0.59 and 2.0 µmol L-1 respectively. The method was applied using mineral water samples and was shown to provide repeatability less than 6.98% and accuracy obtained through recovery essays between 81.1 and 104.6% for the determination of nitrate in this type of sample.

Determination of Nitrate in Vegetables by Continuous Flow: Interlaboratory Study

1994 ◽  
Vol 77 (6) ◽  
pp. 1522-1529 ◽  
Author(s):  
Paul R Beljaars ◽  
Remmelt Van Duk ◽  
Geertrutoa M Van Der Horst
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Continuous Flow ◽  
Collaborative Study ◽  
Leafy Vegetables ◽  
Collaborative Studies ◽  
Relative Standard ◽  
Metallic Cadmium ◽  
Inspection Service

Abstract A collaborative study for the determination of nitrate in leafy vegetables, such as endive, lettuce, spinach, and beetroot, by continuous flow (CF) was conducted by the Project Group on Collaborative Studies of the Inspectorate for Health Protection, Food Inspection Service, in The Netherlands. After extraction with water and filtration, samples were cleaned up by dialysis in the CF system. Extracted nitrates were reduced to nitrite in the system by metallic cadmium, and then the nitrite was reacted with sulfanilamide and N-naphthylethylenediamine to form a reddish-purple azo dye. This dye was measured colorimetrically at 530 nm. Fourteen vegetable samples (including 7 blind duplicates) containing nitrate at ca 900 to 5200 mg/kg were analyzed singly by the proposed procedure by 13 laboratories. The data were analyzed by the International Union for Pure and Applied Chemistry (IUPAC)–International Organization for Standardization (ISO)–AOAC protocol for statistics. One collaborator was identified as an outlier for all results. For all samples analyzed, the repeatability relative standard deviation values varied from 1.7 to 5.5%, whereas the reproducibility relative standard deviation values ranged from 3.3 to 5.9%.

The study of variability in some wool traits in a coarse wool breed of sheep

1973 ◽  
Vol 80 (2) ◽  
pp. 233-238 ◽  
Author(s):  
R. A. Guirgis
Keyword(s):  
Statistical Analysis ◽  
Standard Deviation ◽  
Major Part ◽  
Fibre Diameter ◽  
Coefficient Of Determination ◽  
Main Contributor ◽  
Total Variability ◽  
The Mean ◽  
Staple Length

SummaryWool samples from 47 Barki yearlings were taken from five positions during two years to study the variability in the fleece, the cause of variability and associations between different fleece traits. Statistical analysis has indicated the following significant points.An antero-posterior gradient occurred in the different traits under study. When medullation was discarded, though it was of a low magnitude (3·9%), a reduction of 5·89% in the mean fibre diameter and of 18·33% in its standard deviation occurred.The position most representative of the whole fleece varied with the trait. It is recommended to take three sampling positions forming a triangle, withers, mid-side and hip, to represent the Barki fleece.The animals contributed the major part in the variability of mean fibre diameter (1), the standard deviation of fibre diameter (S.D.1), percentage medullation, mean fibre diameter after discarding the medullated fibres (2), the standard deviation of fibre diameter after discarding the medullated fibres (S.D.2), the contribution of medullation to the total variability, percentage fine fibres and percentage coarse fibres. The positions were the main contributor to the variability of percentage kemp fibres, staple length, medullation index and to a certain extent to that of the kemp score. The year played a significant part in the variability except for 2 and S.D.2.The highest correlations with the standard deviation of fibre diameter were those of percentage medullation and kemp score. These three variables when considered separately accounted for 0·47, 0·35 and 0·31 respectively of the variability in S.D.Equations were obtained to predict the standard deviation from both the mean fibre diameter and the percentage medullation and to predict the mean fibre diameter from the staple length and the kemp score. The coefficient of determination of the first set of equations ranged from 0·47 to 0·56 while that of the second set ranged between 0·07 and 0·51 for different positions.

scholarly journals Pengaruh Kualitas Produk Terhadap Loyalitas Pelanggan Air Mineral Alfamart Pada Toko Alfamart Cabang Cikokol

2021 ◽  
Vol 1 (1) ◽  
pp. 29-39
Author(s):  
Mada Faisal Akbar ◽  
Hadion Wijoyo ◽  
Adhi Wibowo
Keyword(s):  
Product Quality ◽  
Customer Loyalty ◽  
Mineral Water ◽  
Hypothesis Test ◽  
Sampling Technique ◽  
Coefficient Of Determination ◽  
Linear Regression Equation ◽  
Simple Linear Regression ◽  
Quality Instruments

Alfamart is also one of the mini market stores in Indonesia which also applies the importance of providing the best service for each customer and always tries to understand the products that its customers need and want. By offering various kinds of bottled water products, Alfamart strives to satisfy and provide convenience to each of its customers in making purchase transactions. In this study, researchers used a saturated sampling technique in determining the number of samples. Based on the number of population and the sampling technique used, the number of samples in this study was 75 respondents. Based on the results of the distribution of product quality instruments (x) to 75 Alfamart mineral water customers, it shows that, product quality (x) in mineral water, customer loyalty (y) for mineral water at Alfamart Cikokol Tangerang Branch is currently good. The effect of product quality on customer loyalty of Alfamart mineral water at Alfamart store Cikokol Tangerang branch shows that, the simple linear regression equation Y = 15.42 + 0.39. (x) means that this equation can estimate / calculate the effect of product quality (x) on customer loyalty (y). If the product quality (x) is increased one-by-one, customer loyalty (y) will increase to 0.39 and if the product quality is increased to 10 then customer loyalty will increase to 3.9. The coefficient of determination of the product quality variable (x) contributed 41.90% to the customer loyalty variable (y) at Alfamart Stores Cikokol Tangerang branch. In the hypothesis test t count 7,256 t table 1,993, thus this study proves that "there is a significant effect of product quality on customer loyalty of Alfamart Mineral Water at Alfamart Stores Cikokol Branch"

Emission Spectrographic Determination of Hafnium in Zirconium Dioxide

1973 ◽  
Vol 27 (2) ◽  
pp. 129-132 ◽  
Author(s):  
G. D. Stempel
Keyword(s):  
Standard Deviation ◽  
Sample Preparation ◽  
Relative Standard Deviation ◽  
Zirconium Dioxide ◽  
Spectrographic Determination ◽  
Relative Standard ◽  
Spectrographic Method ◽  
Analytical Range ◽  
Zirconium Metal

An emission spectrographic method of analysis is described in which trace quantities of hafnium are determined in zirconium dioxide. The sample preparation, starting with zirconium metal sheet or zirconium dioxide, is discussed in detail. The excitation source used is an ac spark. Quantitation was achieved with a dual grating emission spectrograph. The analytical range of the method for the analysis of hafnium is 5 to 1000 ppm with a relative standard deviation of 9.7%.

scholarly journals A Fluorimetric Method Based on an Imidazole Compound for Cu2+ Determination in Tap Water

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Zafer Ocak
Keyword(s):  
Standard Deviation ◽  
Water Samples ◽  
Fluorescence Spectra ◽  
Tap Water ◽  
External Calibration ◽  
Relative Standard ◽  
Sensor Properties ◽  
Detection And Quantification ◽  
Imidazole Compound

Ion sensor properties of 4-(1-(4-hydroxy-3-methoxybenzyl)-1H-benzo[d]imidazol-2-yl)-2-methoxyphenol (L) in acetonitrile-water (1 : 1) were evaluated by fluorescence spectrometry. Pronounced quenching in the fluorescence spectra of the ligand was only observed for the Cu2+ ion among many metal ions. Linear fluorescence responses of the ligand at 360 nm as the function of the Cu2+ concentration were used for the determination of the Cu2+ ion in spiked tap water samples. Recovery values (R%) were satisfactory, and relative standard deviation (RSD%) was below 5.00 in intraday and interday measurements. Detection and quantification limits were 0.28 and 0.84 μg/L, respectively. The assay based on external calibration only took a few minutes.

scholarly journals Correlation Between Arm Muscle Power and Badminton Smash Skill

2021 ◽  
Vol 10 (1) ◽  
pp. 16-20
Author(s):  
Myrza Akbari ◽  
Johaidah Mistar ◽  
Rahmati Ismail ◽  
Razali Ismail
Keyword(s):  
Data Analysis ◽  
Standard Deviation ◽  
Muscle Power ◽  
Coefficient Of Determination ◽  
Average Standard Deviation ◽  
Correlational Research ◽  
The Mean ◽  
Shot Put ◽  
Research Type

Based on theoretical studies, the variable arm muscle power is an important factor of physical condition in supporting badminton smash skills. This study aims to determine the correlation between arm muscle power and badminton smash skills. This research uses a quantitative approach with correlational research type. The research sample consisted of 73 people who were selected from physical Serambi Mekkah University, Banda Aceh. The research instruments used for each varibale were: arm muscle power using the shot put test instrument, while for badminton smash skills using a process and result test developed by the author himself, the data analysis stages consisted of calculating the mean, standard deviation.. The stages of data analysis carried out were the calculation of the average, standard deviation, determination of the t score, calculation of the correlation and the t test to determine the significance of the correlation between variables. Based on the analysis of research data, The correlation between arm muscle power and badminton smash skills is (r = 0.88. which means that there is a significant correlation between arm muscle power and badminton smash skills. Based on the calculation of the coefficient of determination, it was also found that arm muscle power contributed 78.68% to badminton smash skills.

scholarly journals RELATIONSHIP OF BALANCE AND LEG MUSCLE STRENGTH WITH THE ABILITY OF STRAIGHT KICKS IN PENCAK SILAT ATHLETES FOSTERED BY DISPORA ACEH BESAR IN 2020

2020 ◽  
Vol 1 (2) ◽  
pp. 183-191
Author(s):  
Tuti Sarwita ◽  
Zulheri Is
Keyword(s):  
Standard Deviation ◽  
Muscle Strength ◽  
Research Method ◽  
Coefficient Of Determination ◽  
Male Athletes ◽  
Research Results ◽  
Leg Muscle ◽  
Relationship Of ◽  
The Relationship

Pencak silat is a sport that has long been competed in the national and international arena. The problems in this research are as follows: How is the relationship between balance and leg muscle strength with the ability of straight kicks to the big Aceh Dispora-assisted Pencak silat athletes. The purpose of this study was to determine how much the relationship between balance and leg muscle strength and the ability of straight kicks in the Pencak silat athletes assisted by the Aceh Besar Dispora. This study uses a quantitative approach with the type of correlation research method. The objective of this research is to determine whether there is a relationship between the two or three variables studied. As for the population in this study, all male athletes of the Pencak Silat Assisted by Dispora Aceh Besar, totaling 7 people. Based on the results of the research on the balance of the Pencak Silat athletes assisted by the Aceh Dispora with an average balance of 45 and a standard deviation of 9.4. While the results of leg muscle strength are 208 on average and the standard deviation of leg muscle strength is 46.84. From the calculation of the coefficient of determination of the balance contribution, the leg muscle strength was 2.161 in the very strong category. From the results of the percentage of research results Balance to the Ability of Straight Kicks 0.29%, while the results of leg muscle strength are 208 on average and the standard deviation of leg muscle strength is 46.84. From the calculation of the coefficient of determination of the balance contribution, the leg muscle strength is 2.161 in the very strong category. From the results of the percentage of research results Balance to the Ability of Straight Kicks 0.29%.

scholarly journals Liquid Chromatographic Determination of Flumetsulam in Soybeans

2005 ◽  
Vol 88 (5) ◽  
pp. 1463-1468 ◽  
Author(s):  
Michael Moawad ◽  
Cheang S Khoo
Keyword(s):  
Standard Deviation ◽  
Phosphate Buffer ◽  
Mobile Phase ◽  
Limit Of Detection ◽  
Coefficient Of Determination ◽  
Ionization Mass ◽  
Soybean Sample ◽  
Soybean Extract ◽  
Relative Standard

Abstract A liquid chromatography (LC) method with UV detection is reported for the determination of the sulfonamide herbicide flumetsulam in soybeans. The ground soybean sample was partitioned between methanol and hexane. The hexane removed the lipids, and the methanol layer containing the analyte was further partitioned between dichloromethane and aqueous phosphate buffer at pH 7.0. The aqueous layer, containing the analyte, was acidified to pH 2.2 and partitioned with fresh dichloromethane. The dichloromethane layer containing the analyte was evaporated, and the residue was dissolved in the LC mobile phase for analysis. A polar embedded C18 column was used with a mobile phase of pH 2.2 aqueous phosphate buffer–acetonitrile (68 + 32), run isocratically with detection at 225 nm. The average recovery was 82% with a relative standard deviation (RSD) of 10%. A coefficient of determination of R2 = 0.9992 was achieved for the analyte calibration curve, from 0.005 to 1 μg/mL. The limit of detection, determined from 3 times the standard deviation of 7 replicate extractions of the lowest fortification level (0.01 μg/g, was 0.005 μg/g with an RSD of 22%. LC/electrospray ionization/mass spectrometry in the positive-ion mode was used for identity confirmation of flumetsulam in the fortified soybean extract. The ions at m/z 326, 348, and 129 were observed.

scholarly journals Determination of formaldehyde in production solutions using the piezoelectric sensors

2021 ◽  
Vol 25 (2) ◽  
pp. 140-145
Author(s):  
A. A. Merenkova ◽  
◽  
K. V. Zhuzhukin ◽  
A. N. Zyablov ◽  
L. I. Belchinskaya ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Piezoelectric Sensor ◽  
Calibration Graph ◽  
Piezoelectric Sensors ◽  
Coefficient Of Determination ◽  
Relative Standard ◽  
Production Solutions ◽  
Industrial Solutions

In the current work, piezoelectric sensors based on a molecular imprinted polymer (MIP) were obtained for determining the formaldehyde in the industrial solutions of a woodworking plant. The synthesis was carried out directly on the surface of the piezoelectric sensor. In the process of the two-stage thermoimidization of the obtained prepolymerization mixture, a molecular imprinted polyimide of formaldehyde was formed. For the analysis of the supra-resin part of the effluent of the Grafskaya kuhnya LLC (Voronezh) woodworking enterprise, which was obtained by the dry distillation of wood, the method of a calibration graph having a linear relationship was used; the coefficient of determination R2 = 0.97. The detection limit of the piezosensor was 0.6 ∙ 10–4 mol / dm3, the range of determined concentrations was 1.0 – 10–4 mol / dm3. The comparison of piezoelectric sensors based on the polymer without imprints and based on the polymer with imprints of formaldehyde showed high selectivity of the latter for the target molecule. The calculated imprinting factor was 28.3, the coefficient of selectivity with respect to phenol was 0.05, which indicated the selectivity of the modified sensor to formaldehyde. The verification of the correctness of the determination of formaldehyde in the model and production solutions was carried out using the "added-found" method. It was found that the MIP-based sensor was sensitive only to formaldehyde, the relative standard deviation did not exceed 2.0%. In order to assess the effect of the object matrix (formaldehyde) on the value of the resonant frequency, the standard addition method was used. It was determined that the matrix did not affect the value of the analytical signal, the relative standard deviation was 2.8%. For the re-analysis, the piezoelectric sensor was exposed to the regeneration in the oven at 50 ⁰С. The proposed method for determining the concentration of the formaldehyde using the MIP-sensor allowed controlling the content of the toxicant in the industrial solutions.

An Automated Procedure for the Determination of Ammonia in Tobacco

1972 ◽  
Vol 6 (4) ◽  
Author(s):  
P.F. Collins ◽  
W.W. Lawrence ◽  
J.F. Williams
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Distillation Method ◽  
Relative Standard ◽  
Tobacco Sample ◽  
Automated Determination

AbstractA procedure for the automated determination of ammonia in tobacco has been developed. Ammonia is extracted from the ground tobacco sample with water and is determined with a Technicon Auto Analyser system which employs separation of the ammonia through volatilization followed by colourimetry using the phenate-hypochlorite reaction. The procedure has been applied to a variety of tobaccos containing from 0.02 to 0.5 % ammonia with an overall relative standard deviation of 2 %. The accuracy of the procedure as judged by recovery tests and by comparison to a manual distillation method is considered adequate

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