Modification of the USP Chemical Method for Determining Vitamin D in Evaporated Milk

1965 ◽  
Vol 48 (6) ◽  
pp. 1212-1217
Author(s):  
S W Jones ◽  
J B Wilkie ◽  
D A Libby
Keyword(s):  
Vitamin D ◽  
Standard Deviation ◽  
Sample Preparation ◽  
Relative Standard Deviation ◽  
Chemical Method ◽  
Statistical Data ◽  
Color Reaction ◽  
Bioassay Method ◽  
Modified Method ◽  
Relative Standard

Abstract The USP XVI chemical method for vitamin D in USP products has been substantially modified and applied to evaporated milk containing approximately 30 units of vitamin D per fluid ounce. A major modification is a 15 second reading at 500 mμ which most nearly represents the vitamin D content of the sample. An improved sample preparation eliminates much of the background interference, which also produces a color reaction. This method, when applied to a variety of samples, will show a relative standard deviation of 10%. Statistical data are presented to compare the modified method with the rat bioassay method for assaying vitamin D in evaporated milk.

Sample Preparation for Volatile Oil Analysis of Cassia Bark

1995 ◽  
Vol 78 (5) ◽  
pp. 1233-1237
Author(s):  
Charles M Zapf ◽  
Mark Parrish
Keyword(s):  
Standard Deviation ◽  
Sample Preparation ◽  
Systematic Error ◽  
Relative Standard Deviation ◽  
Temperature Increase ◽  
Volatile Oil ◽  
Oil Analysis ◽  
Reasonable Care ◽  
Relative Standard ◽  
Multiple Samples

Abstract We established that the choice of the laboratory mill has little effect on steam-distillable volatile oil (VOSD) analysis of Cassia bark when reasonable care is used in preparing single samples. When multiple samples are milled, caution is advised to avoid temperature increase. Data from 11 laboratories are presented for 4 test samples. Participating laboratories milled 200 g samples, and the variation of the resulting VOSD in the ground spice could not be attributed to the different grind-size profiles measured. The estimated systematic error due to type of mill was 0.04 mL/100 g. This represents a relative standard deviation of 2.2% for the lowest average volatile oil levels.

Liquid Chromatographic Determination of Narasin in Feed Premixes

1985 ◽  
Vol 68 (3) ◽  
pp. 417-418 ◽  
Author(s):  
Raymond L Hussey ◽  
Thomas D Macy ◽  
John Moran ◽  
Andrew Loh
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Chromatographic Determination ◽  
Bioassay Method ◽  
Water Solvent ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method has been developed to determine narasin in feed premixes. Narasin is extracted from the premix with a methanol-water solvent, and the extracted solution is assayed by using LC. Recovery of narasin from a 12.5 g/lb premix is quantitative (100%), with a relative standard deviation of 1.44%. The results correlated well (coefficient 0.92) with a turbimetric bioassay method.

The Influence of Particle Diameter on Analytical Results

2014 ◽  
Vol 599-601 ◽  
pp. 196-200
Author(s):  
Feng Xie ◽  
Hong Tan ◽  
Zhan Bin Li ◽  
Hong Bo Yang ◽  
Hai Da Sun ◽  
...  
Keyword(s):  
Analytical Chemistry ◽  
Particle Size ◽  
Standard Deviation ◽  
Sample Preparation ◽  
Relative Standard Deviation ◽  
Particle Diameter ◽  
Analytical Results ◽  
Relative Standard ◽  
First Time

In analytical chemistry, particle diameter is very important during the sample preparation. A model is presented describing the effects of particle diameter on the content of analyte determines the size of the particle; and the particle size determines the weight of samples and relative standard deviation in the results. This new methodology for the optimisation of physical sample preparation is applied for the first time. Based on this relationship, we can find an extensive application in analytical chemistry.

scholarly journals QUANTITATION OF METFORMIN IN URINE BY RP-HPLC METHOD AND ITS APPLICATION IN PHARMACOKINETICS

2021 ◽  
pp. 67-71
Author(s):  
MARY REBECCA Y. ◽  
SUDHA V. ◽  
VIJAYAKUMAR A. ◽  
HEMANTH KUMAR A. K.
Keyword(s):  
Particle Size ◽  
Standard Deviation ◽  
Sample Preparation ◽  
Relative Standard Deviation ◽  
Urine Sample ◽  
Hplc Method ◽  
Uv Detection ◽  
Pharmacokinetic Studies ◽  
Rp Hplc ◽  
Relative Standard

Objective: To develop and validate an easy and sensitive HPLC method for quantitation of metformin in urine. Methods: The technique involved deproteinisation of urine sample with methanol and analysis of the supernatant the usage of Zorbax 300–SCX, 4.6 X 150 mm ID, 5 µm particle size and UV detection at a wavelength of 233 nm. Results: The assay was specific for metformin and linear from 1.25 to 50.0μg/ml. The relative standard deviation of intra-and inter-day assays was lesser than 7%. The recovery of metformin from urine ranged from 97-103%. Conclusion: An easy and sensitive HPLC approach for quantitation of metformin in urine had been developed. Due to its simplicity in sample preparation and instrumentation, this technique can be used for pharmacokinetic studies of metformin in urine samples.

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%.

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

How Certain Are the Reported Ionic Conductivities of Thiophosphate-Based Solid Electrolytes? an Interlaboratory Study

2020 ◽  
Author(s):  
Saneyuki Ohno ◽  
Tim Bernges ◽  
Johannes Buchheim ◽  
Marc Duchardt ◽  
Anna-Katharina Hatz ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Ionic Conductivity ◽  
Relative Standard Deviation ◽  
Solid Electrolytes ◽  
Ionic Conductivities ◽  
Ionic Conductors ◽  
Energy Storage Devices ◽  
Activation Barriers ◽  
Storage Devices ◽  
Relative Standard

<p>Owing to highly conductive solid ionic conductors, all-solid-state batteries attract significant attention as promising next-generation energy storage devices. A lot of research is invested in the search and optimization of solid electrolytes with higher ionic conductivity. However, a systematic study of an <i>interlaboratory reproducibility</i> of measured ionic conductivities and activation energies is missing, making the comparison of absolute values in literature challenging. In this study, we perform an uncertainty evaluation via a Round Robin approach using different Li-argyrodites exhibiting orders of magnitude different ionic conductivities as reference materials. Identical samples are distributed to different research laboratories and the conductivities and activation barriers are measured by impedance spectroscopy. The results show large ranges of up to 4.5 mScm<sup>-1</sup> in the measured total ionic conductivity (1.3 – 5.8 mScm<sup>-1</sup> for the highest conducting sample, relative standard deviation 35 – 50% across all samples) and up to 128 meV for the activation barriers (198 – 326 meV, relative standard deviation 5 – 15%, across all samples), presenting the necessity of a more rigorous methodology including further collaborations within the community and multiplicate measurements.</p>

scholarly journals Indirect and Direct Determination of the Casein Content of Milk by Kjeldahl Nitrogen Analysis: Collaborative Study

1998 ◽  
Vol 81 (4) ◽  
pp. 763-774 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming
Keyword(s):  
Standard Deviation ◽  
Nitrogen Content ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
Direct Determination ◽  
Raw Milk ◽  
Method Performance ◽  
Relative Standard ◽  
Milk Casein

Abstract The classic method for determination of milk casein is based on precipitation of casein at pH 4.6. Precipitated milk casein is removed by filtration and the nitrogen content of either the precipitate (direct casein method) or filtrate (noncasein nitrogen; NCN) is determined by Kjeldahl analysis. For the indirect casein method, milk total nitrogen (TN; Method 991.20) is also determined and casein is calculated as TN minus NCN. Ten laboratories tested 9 pairs of blind duplicate raw milk materials with a casein range of 2.42- 3.05℅ by both the direct and indirect casein methods. Statistical performance expressed in protein equivalents (nitrogen ⨯ 6.38) with invalid and outlier data removed was as follows: NCN method (wt%), mean = 0.762, sr = 0.010, SR = 0.016, repeatability relative standard deviation (RSDr) = 1.287℅, reproducibility relative standard deviation (RSDR) = 2.146%; indirect casein method (wt℅), mean = 2.585, repeatability = 0.015, reproducibility = 0.022, RSDr = 0.560℅, RSDR = 0.841; direct casein method (wt℅), mean = 2.575, sr = 0.015, sR = 0.025, RSDr = 0.597℅, RSDR = 0.988℅. Method performance was acceptable and comparable to similar Kjeldahl methods for determining nitrogen content of milk (Methods 991.20, 991.21,991.22, 991.23). The direct casein, indirect casein, and noncasein nitrogen methods have been adopted by AOAC INTERNATIONAL.

scholarly journals A computer-controlled potentiometric/spectrophotometric titrator

1988 ◽  
Vol 10 (2) ◽  
pp. 95-100
Author(s):  
John D. Stong
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Bromophenol Blue ◽  
System Control ◽  
Data Format ◽  
Relative Standard ◽  
Spectrophotometric Titrations ◽  
Computer Controlled ◽  
Major Attention ◽  
Diode Array Spectrophotometer

A laboratory computer controlled potentiometric titrator interfaced to a diode array spectrophotometer is described. The titrator consists of widely used, commercially available components; therefore, major attention is given to modes of interconnection and software implementation in data format and system control. Replicate potentiometric titrations of glycines gave a relative standard deviation in titre of 1.035% and a relative standard deviation in pH of 0.745%. Replicate spectrophotometric titrations of bromophenol blue were analysed at three wavelengths to yield pKa= 3.898 ± 0.075 (1.9% rsd).Methods of data presentation and manipulation are presented.

Sign in / Sign up

Export Citation Format

Share Document