Interlaboratory comparison of dynamic olfactometry in Central Europe 2000

2001 ◽  
Vol 44 (9) ◽  
pp. 27-32 ◽  
Author(s):  
D. Mannebeck ◽  
H. Mannebeck
Keyword(s):  
Central Europe ◽  
Hydrogen Sulphide ◽  
Interlaboratory Comparison ◽  
European Standard ◽  
Mean Values ◽  
Repeatability And Reproducibility ◽  
Odour Concentration ◽  
Standard Deviations ◽  
Dynamic Olfactometry

This paper presents the results of an interlaboratory comparison (ringtest) on olfactometry with 31 participants from four countries in Central Europe. The aim was to give evidence of the performance of dynamic olfactometry on the basis of the European Standard prEN 13725 (Draft) “Determination of odour concentration with dynamic olfactometry”. The test included the analysis of three individual substances (n-butanol, hydrogen sulphide, tetrahydrothiophen) as well as a natural odour mixture (coffee flavour) to compare mean values and the standard deviations of results for the investigated samples. It was confirmed that laboratories working in compliance with the requirements of the new standard achieve a significantly better repeatability and reproducibility than those that are not compliant.

Determination of Menthol in Cigarette Tobacco Filler

1967 ◽  
Vol 50 (4) ◽  
pp. 770-773
Author(s):  
Charles L Tucker ◽  
C L Ogg
Keyword(s):  
Chromatographic Method ◽  
Colorimetric Method ◽  
Cigarette Tobacco ◽  
Mean Values ◽  
Accuracy And Precision ◽  
Standard Deviations ◽  
Gas Chromatographic Method

Abstract A gas chromatographic and a colorimetric method for determining menthol in cigarette tobacco filler were studied collaboratively by 15 laboratories. No statistically significant differences were found in the precisions within or between laboratories. There were no significant differences between mean values for the two methods for any of the samples. Trends toward higher mean values for the colorimetric method and lower within-laboratory standard deviations for the gas chromatographic method were noted. Remarks by collaborators suggest that the accuracy and precision of the colorimetric method may be improved, and further studies are recommended.

scholarly journals Interlaboratory Comparison for the Determination of Five Residual Organochlorine Pesticides in Ginseng Root Samples by Gas Chromatography

2007 ◽  
Vol 90 (4) ◽  
pp. 1133-1141 ◽  
Author(s):  
Mei-Fung Kong ◽  
Serena Chan ◽  
Yiu-Chung Wong ◽  
Siu-Kay Wong ◽  
Della Wai-Mei Sin
Keyword(s):  
Measurement Uncertainty ◽  
Organochlorine Pesticides ◽  
Interlaboratory Comparison ◽  
Analytical Data ◽  
Quality Criterion ◽  
Asia Pacific ◽  
Ginseng Root ◽  
Mean Values ◽  
Z Scores

Abstract An interlaboratory comparison study for the determination of 5 residual organochlorine pesticides (hexachlorobenzene and 4 hexachlorocyclohexane isomers) in ginseng root was performed. This program [Asia Pacific Laboratory Accreditation Cooperation (APLAC) T049] was the first of its kind for an herbal matrix and involved the participation of 70 laboratories from 26 countries worldwide. Consensus mean values were computed statistically from the reported results, which were eventually used to assess the performance of individual laboratories in terms of the z-scores. The distribution of analytical data was found to be widespread, with standard deviation ranging from 43.9 to 55.9%, and the result patterns obtained were similar to those residue pesticide programs using other matrixes. Although the estimation of measurement uncertainty is a crucial requirement for all quantitative tests for laboratories that meet the requirements of International Organization for Standardization/International Electrotechnical Commisssion (ISO/IEC) 17025, some laboratories in this program had difficulties and showed unfamiliarity with respect to that quality criterion. It was recommended that laboratories review and rectify the situation promptly so that they would have a better understanding of measurement uncertainty or the test service provided.

Liquid Chromatographic Method for Determination of Iodine in Milk: Collaborative Study

1993 ◽  
Vol 76 (4) ◽  
pp. 711-719 ◽  
Author(s):  
David Sertl ◽  
William Malone ◽  
◽  
P Beljaars ◽  
C Blake ◽  
...  
Keyword(s):  
Membrane Filter ◽  
Collaborative Study ◽  
Reversed Phase ◽  
Powdered Milk ◽  
Insoluble Material ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract Nine laboratories participated in an AOAC International/ International Dairy Federation collaborative study on a liquid chromatographic (LC) method for determination of iodine in milk. Liquid milk is passed through a 25 000 MW membrane filter to remove protein and insoluble material. Iodine (in the form of iodide) in the clear filtrate is separated by reversed-phase ion-pair LC and is detected electrochemically. Participants analyzed 2 commercial pasteurized whole milks and 5 nonfat dry milk powders in blind duplicate. Each sample was tested in duplicate on 2 days. Repeatability and reproducibility standard deviations (sr and SR, respectively) and repeatability and reproducibility relative standard deviations (RSDr and RSDR, respectively) for determinations of iodine in whole milk (mean recovery, 86.7%) were as follows: sr, 22 μg/L; SR, 22 μg/L; RSDr, 8.2%; and RSDR, 8.3%. For powdered milk (mean recovery, 91 %), the values were as follows: sr, 0.14 μg/g; SR, 0.22 μg/g; RSDr, 9.0%; and RSDR, 12.7%. The method was adopted first action by AOAC International.

scholarly journals Determination of Sex Ratio In Bovine Semen Using SYBR Green Real-Time PCR

2022 ◽  
Author(s):  
Vemula Harshini ◽  
S.M.K. Karthickeyan ◽  
K.G P. Kumarasamy ◽  
Tirumurugaan ◽  
C. Jeevan
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Sybr Green ◽  
Pcr Assay ◽  
Mean Values ◽  
Bovine Semen ◽  
Routine Basis ◽  
Repeatability And Reproducibility ◽  
The Mean

Abstract A SYBR green real-time PCR assay was developed to find out the sex skewness in bovine sex-sorted semen samples. The qPCR assay of PLP and SRY genes revealed the mean values of X- and Y-bearing spermatozoa as 50.24 ± 0.65 and 49.75 ± 0.62 per cent in unsorted, and 91.80 ± 0.79 and 8.20 ± 0.73 per cent in X-enriched semen samples respectively.. The amplification efficiencies of the PLP and SRY primers were 99.25 and 98.03 per cent respectively. The method was validated by a series of repeatability and reproducibility assays which revealed low co-efficients of variations as 2.19 and 3.12 per cent respectively Thus becoming a reliable and inexpensive tool to evaluate the sorted semen on routine basis and validation of other sperm sexing technologies.

scholarly journals Determination of Fumonisins B1 and B2 in Corn and Corn Flakes by Liquid Chromatography with Immunoaffinity Column Cleanup: Collaborative Study

2001 ◽  
Vol 84 (6) ◽  
pp. 1828-1838 ◽  
Author(s):  
Angelo Visconti ◽  
Michele Solfrizzo ◽  
Annalisa De Girolamo ◽  
H Bresch ◽  
P Burdaspal ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Immunoaffinity Column ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Double Extraction ◽  
Standard Deviations ◽  
Corn Flakes ◽  
Liquid Chromatographic ◽  
Fumonisins B1 And B2

Abstract A liquid chromatographic (LC) method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn and corn flakes was collaboratively studied by 23 laboratories, which analyzed 5 blind duplicate pairs of each matrix to establish the accuracy, repeatability, and reproducibility characteristics of the method. Fumonisin levels in the corn ranged from <0.05 (blank) to 1.41 μg/g for FB1 and from <0.05 to 0.56 μg/g for FB2, whereas in the corn flakes they ranged from <0.05 to 1.05 μg/g for FB1 and from <0.05 to 0.46 μg/g for FB2. The method involved double extraction with acetonitrile–methanol–water (25 + 25 + 50), cleanup through an immunoaffinity column, and LC determination of the fumonisins after derivatization with o-phthaldialdehyde. Relative standard deviations for the within-laboratory repeatability (RSDr) of the corn analyses ranged from 19 to 24% for FB1 and from 19 to 27% for FB2; for the corn flakes analyses, RSDr ranged from 9 to 21% for FB1 and from 8 to 22% for FB2. Relative standard deviations for the between-laboratories reproducibility (RSDR) of the corn analyses ranged from 22 to 28% for FB1 and from 22 to 30% for the FB2; for corn flakes analyses, RSDR ranged from 27 to 32% for FB1 and from 26 to 35% for FB2. Mean recoveries of FB1 and FB2 from corn spiked with FB1 at 0.80 μg/g and with FB2 at 0.40 μg/g were 76 and 72%, respectively; for corn flakes spiked at the same levels recoveries were 110 and 97% for FB1 and FB2, respectively. HORRAT ratios for the analyses of corn ranged from 1.44 to 1.53 for FB1 and from 0.96 to 1.48 for FB2, whereas for corn flakes they ranged from 1.60 to 1.82 for FB1 and from 1.39 to 1.68 for FB2.

Comparison of Kjeldahl Method for Determination of Crude Protein in Cereal Grains and Oilseeds with Generic Combustion Method: Collaborative Study

1993 ◽  
Vol 76 (4) ◽  
pp. 780-786 ◽  
Author(s):  
Ronald C Bicsak ◽  
◽  
R Boles ◽  
R Cathey ◽  
V Collins ◽  
...  
Keyword(s):  
Crude Protein ◽  
Animal Feed ◽  
Collaborative Study ◽  
Combustion Method ◽  
Cereal Grains ◽  
Relative Standard ◽  
Kjeldahl Method ◽  
Repeatability And Reproducibility ◽  
Standard Deviations

Abstract Seven laboratories participated in a collaborative study to extend the applicability of the AOAC generic combustion method for determination of crude protein in animal feed (990.03) to include determination in cereal grains and oilseeds. In the study, method 990.03 was compared with the AOAC mercury catalyst Kjeldahl method for determination of protein in grains (979.09) and crude protein in animal feed (954.01). The study also evaluated the effect on the results of fineness of grind. For determination of crude protein in grains and oilseeds by the combustion method, standard deviations for repeatability and reproducibility ranged from 0.10 to 0.37 and from 0.25 to 0.54, respectively, and relative standard deviations for repeatability and reproducibility ranged from 0.77 to 2.57% and from 1.24 to 3.15%, respectively. The combustion method was adopted first action by AOAC International for determination of crude protein in cereal grains and oilseeds containing 0.2- 20% nitrogen.

Gravimetric Determination of Moisture and Ash in Meat and Meat Products: NMKL Interlaboratory Study

1992 ◽  
Vol 75 (6) ◽  
pp. 1016-1022 ◽  
Author(s):  
Kurt Kolar
Keyword(s):  
Collaborative Study ◽  
Meat Products ◽  
Drying Method ◽  
Fresh Meat ◽  
Constant Weight ◽  
Mean Values ◽  
Significant Difference ◽  
Aoac Method ◽  
Repeatability And Reproducibility

Abstract Fourteen laboratories participated in a collaborative study of gravimetric methods for determination of moisture and ash in meat and meat products. The determination of moisture by drying without sand at 102-105C for 16-18 h and to constant weight was compared with the official NMKL method using drying with sand to constant weight. The incineration was performed at 550°C. The method was tested on 16 blind duplicate samples of fresh meat and meat products ranging in moisture content from 44.1 to 74.8 g/100 g, and in ash content from 1.0 to 5.4 g/100 g. Drying without sand for 16-18 h and to constant weight gave no significant difference. Therefore, the labor-intensive drying to constant weight is not necessary to obtain reliable results. In comparison with the official NMKL method based on drying with sand, the mean values, repeatability, and reproducibility of the drying method without sand for 16-18 h agree very well. Therefore, there is no reason to retain the more complicated and labor-intensive sand drying method. The conditions of the proposed method differ only slightly from the conditions used in the official AOAC method, 950.46 B(a). The collaborative results for the determination of both moisture and ash gave estimates for precision according to the HORRAT values

APPLICATION OF PIXE TO DETERMINATION OF ELEMENTS IN THE PLACENTA, MATERNAL BLOOD AND CORD BLOOD

1997 ◽  
Vol 07 (03n04) ◽  
pp. 211-217 ◽  
Author(s):  
Yoshito Watanabe ◽  
Yoshie Takubo ◽  
Masae Yukawa ◽  
Yoshikazu Nishimura ◽  
Hitoshi Imaseki ◽  
...  
Keyword(s):  
Cord Blood ◽  
Maternal Blood ◽  
Pixe Analysis ◽  
Blood Samples ◽  
Mean Values ◽  
The Mean ◽  
Standard Deviations ◽  
Homogenize Sample ◽  
Cu And Zn

PIXE technique was applied to the measurement of elements in the placenta, maternal blood and cord blood of human. The elements determined in these samples include Cl , K , Ca , Fe , Cu and Zn . The values obtained by PIXE were compared with those by ICP-AES to test the accuracy of the method. In placental samples, the mean values of K , Fe , Cu and Zn concentrations obtained by the two methods agree, while Ca concentration is lower in PIXE analysis. The values from PIXE, however, show larger variations resulting from inhomogeneity of the placental samples composed of various tissues different in histological functions. In the analysis of blood samples, the results of the two methods agree for Cl , K , Ca , Fe , Cu and Zn , although the standard deviations tend to be larger in PIXE. These results indicate that PIXE is a useful method for the determination of elements in placental and blood samples, although the preparation to homogenize sample is necessary to obtain accurate results.

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