Interlaboratory study of analysis of phenoxymethylpenicillin by liquid chromatography

1998 ◽  
Vol 47 (3-4) ◽  
pp. 152-156 ◽  
Author(s):  
Zhu Yongxin ◽  
E. Roets ◽  
B. Trippen ◽  
Ch. -P. Christiansen ◽  
M. P. Arevalo ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Interlaboratory Study

scholarly journals Immunoaffinity Column Cleanup with Liquid Chromatography Using Post-Column Bromination for Determination of Aflatoxins in Hazelnut Paste: Interlaboratory Study

2005 ◽  
Vol 88 (2) ◽  
pp. 526-535 ◽  
Author(s):  
Hamide Z Senyuva ◽  
John Gilbert
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Aflatoxin B1 ◽  
The United States ◽  
Interlaboratory Study ◽  
Immunoaffinity Column ◽  
Test Portion ◽  
Relative Standard

Abstract An interlaboratory study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for determination of aflatoxin B1 and total aflatoxins in hazelnut paste at European regulatory limits. The test portion was extracted with methanol–water (6 + 4). The extract was filtered, diluted with phosphate-buffered saline (PBS) solution to a specified solvent concentration, and applied to an immunoaffinity column containing antibodies specific to aflatoxins. The aflatoxins were removed from the immunoaffinity column with methanol, and then quantified by reversed-phase LC with post-column derivatization (PCD) involving bromination. The PCD was achieved with electrochemically generated bromine (Kobra Cell®) followed by fluorescence detection (except for one participant who used pyridinum hydrobromide perbromide for bromination). Hazelnut paste, both naturally contaminated with aflatoxins and blank (<0.1 ng/g) for spiking by participants with aflatoxins, was sent to 14 collaborators in Belgium, The Netherlands, Spain, Turkey, the United Kingdom, and the United States. Test portions were spiked at levels of 4.0 and 10.0 ng/g for total aflatoxins by participants using supplied total aflatoxins standards. Recoveries for total aflatoxins and aflatoxin B1 averaged from 86 to 89%. Based on results for naturally contaminated samples (blind duplicates at 3 levels ranging from 4.0 to 11.8 ng/g total aflatoxins), the relative standard deviation for repeatability (RSDr) ranged from 2.3 to 3.4% for total aflatoxins and from 2.2 to 3.2% for aflatoxin B1. The relative standard deviation for reproducibility (RSDR) ranged from 6.1 to 7.0% for total aflatoxins and from 7.3 to 7.8% for aflatoxin B1. The method showed exceptionally good within-laboratory and between-laboratory precision for hazelnut paste, as evidenced by HORRAT values, which in all cases were significantly below target levels, the low levels of determination for both aflatoxin B1 and total aflatoxins.

Interlaboratory study of the analysis of ampicillin by liquid chromatography

1996 ◽  
Vol 14 (8-10) ◽  
pp. 1151-1156 ◽  
Author(s):  
Yongxin Zhu ◽  
M.L. Moreno ◽  
E. Porqueras ◽  
E. Bourke ◽  
A. Bruzzi ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Interlaboratory Study

Validation of a Method for Quantification of Lutein in Spinach Using High-Performance Liquid Chromatography: Interlaboratory Study

2020 ◽  
Vol 103 (4) ◽  
pp. 1073-1080
Author(s):  
Takefumi Sonoda ◽  
*Yusuke Hiejima ◽  
Tomohiro Koiwa ◽  
Masahiro Asano ◽  
Eiichi Kotake ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Spinacia Oleracea ◽  
The Body ◽  
Interlaboratory Study ◽  
Spinacia Oleracea L ◽  
Study Results ◽  
Relative Standard

Abstract Background Lutein is gaining attention as a strong antioxidant contained in foods. It accumulates in the human blood and retina, and is considered to play an important role in the body, especially in the eyes. Objective A method to determine the lutein content of raw spinach (Spinacia oleracea L.) was developed with the aim of its enactment as a Japanese agricultural standard (JAS) measurement method for components beneficial to human health. Methods An interlaboratory study was conducted to evaluate an analytical method for the determination of lutein in spinach. The detection limit and quantification limit of lutein for this method were 0.2 and 0.7 mg/kg, respectively. Twelve participating laboratories independently analyzed test samples (five pairs of blind duplicates) using high-performance liquid chromatography (HPLC). Results After removal of a few outliers, the repeatability relative standard deviation (RSDr), reproducibility (RSDR), and predicted RSDR of the evaluated method were 3.4–7.5, 4.6–13, and 7.5–8.5%, respectively, in a concentration range from 64.9–150 mg/kg. Conclusions The HorRat values (RSDR/predicted RSDR) of the lutein concentration were calculated to be 0.61–1.6. Highlights The study results indicate the acceptable precision of this method.

scholarly journals Immunoaffinity Column Cleanup with Liquid Chromatography for Determination of Aflatoxin B1 in Corn Samples: Interlaboratory Study

2007 ◽  
Vol 90 (3) ◽  
pp. 765-772 ◽  
Author(s):  
Carlo Brera ◽  
Francesca Debegnach ◽  
Valentina Minardi ◽  
Elena Pannunzi ◽  
Barbara De Santis ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Aflatoxin B1 ◽  
Interlaboratory Study ◽  
Precolumn Derivatization ◽  
Immunoaffinity Column ◽  
Relative Standard ◽  
Postcolumn Derivatization

Abstract An interlaboratory study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for the determination of aflatoxin B1 levels in corn samples, enforced by European Union legislation. A test portion was extracted with methanolwater (80 + 20); the extract was filtered, diluted with phosphate-buffered saline solution, filtered on a microfiber glass filter, and applied to an immunoaffinity column. The column was washed with deionized water to remove interfering compounds, and the purified aflatoxin B1 was eluted with methanol. Aflatoxin B1 was separated and determined by reversed-phase LC with fluorescence detection after either pre- or postcolumn derivatization. Precolumn derivatization was achieved by generating the trifluoroacetic acid derivative, used by 8 laboratories. The postcolumn derivatization was achieved either with pyridinium hydrobromide perbromide, used by 16 laboratories, or with an electrochemical cell by the addition of bromide to the mobile phase, used by 5 laboratories. The derivatization techniques used were not significantly different when compared by the Student's t-test; the method was statistically evaluated for all the laboratories. Five corn sample materials, both spiked and naturally contaminated, were sent to 29 laboratories (22 Italian and 7 European). Test portions were spiked with aflatoxin B1 at levels of 2.00 and 5.00 ng/g. The mean values for recovery were 82% for the low level and 84% for the high contamination level. Based on results for spiked samples (blind pairs at 2 levels) as well as naturally contaminated samples (blind pairs at 3 levels), the values for relative standard deviation for repeatability (RSDr) ranged from 9.9 to 28.7%. The values for relative standard deviation for reproducibility (RSDR) ranged from 18.6 to 36.8%. The method demonstrated acceptable within- and between-laboratory precision for this matrix, as evidenced by the HorRat values.

Interlaboratory study of a liquid chromatography method for erythromycin: determination of uncertainty

2003 ◽  
Vol 1010 (1) ◽  
pp. 63-74 ◽  
Author(s):  
P. Dehouck ◽  
Y. Vander Heyden ◽  
J. Smeyers-Verbeke ◽  
D.L. Massart ◽  
R.D. Marini ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Interlaboratory Study ◽  
Chromatography Method ◽  
Liquid Chromatography Method

Interlaboratory study of the analysis of benzylpenicillin by liquid chromatography

1998 ◽  
Vol 707 (1-2) ◽  
pp. 189-193 ◽  
Author(s):  
Zhu Yongxin ◽  
E Roets ◽  
J Loidl ◽  
P Inama ◽  
A Perez ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Interlaboratory Study

Nonaqueous Copper Colorimetric and Silver Titrimetric Methods for Determining Malathion in Technical Grade Malathion and Malathion Formulations from Domestic and Foreign Sources: Interlaboratory Study

1977 ◽  
Vol 60 (5) ◽  
pp. 1148-1153
Author(s):  
Alan R Stiles ◽  
James W Miles ◽  
Richard S Wayne ◽  
Ladene H Newton
Keyword(s):  
Liquid Chromatography ◽  
Excellent Agreement ◽  
Poor Quality ◽  
Interlaboratory Study ◽  
Gas Liquid Chromatography ◽  
Technical Grade ◽  
Water Dispersible ◽  
Coefficients Of Variation

Abstract The nonaqueous copper colorimetric and the silver titrimetric methods for determining malathion were studied. Samples of technical grade malathion and emulsifiable concentrates from 4 countries and samples of water-dispersible powders from 3 countries were used in the study. Nineteen participants in 15 laboratories representing 11 countries took part in the study. The precision obtained within laboratories was excellent. Agreement between laboratories was also quite good with coefficients of variation ranging from 1.05 to 5.31 for the silver method and from 0.65 to 3.52 for the copper method. Results by both methods were high when compared with results obtained by gas-liquid chromatography. This was particularly true for poor quality samples.

First European interlaboratory study of the analysis of benzoxazinone derivatives in plants by liquid chromatography

2004 ◽  
Vol 1047 (1) ◽  
pp. 69-76 ◽  
Author(s):  
E. Eljarrat ◽  
M. Guillamón ◽  
J. Seuma ◽  
B.B. Mogensen ◽  
I.S. Fomsgaard ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Interlaboratory Study

scholarly journals Determination of Ephedrine Alkaloids in Dietary Supplements and Botanicals by Liquid Chromatography/Tandem Mass Spectrometry: Collaborative Study

2003 ◽  
Vol 86 (4) ◽  
pp. 657-668 ◽  
Author(s):  
William A Trujillo ◽  
Wendy R Sorenson ◽  
J Laurensen ◽  
G Luo ◽  
R McClanahan ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Dietary Supplements ◽  
Collaborative Study ◽  
Internal Standard ◽  
Negative Control ◽  
Interlaboratory Study ◽  
Tandem Mass ◽  
Accuracy And Precision ◽  
Ephedra Nevadensis

Abstract An interlaboratory study was conducted to evaluate the accuracy and precision of a method for ephedrine-type alkaloids [i.e., norephedrine (NE), norpseudoephedrine (NPE), ephedrine (E), pseudoephedrine (PE), methylephedrine (ME), and methylpseudoephedrine (MPE)] in dietary supplements and botanicals. The amount of ephedrine-type alkaloids present was determined using liquid chromatography with tandem mass selective detection. The samples were diluted to reflect a concentration of 0.0200 to 1.00 μg/mL for each alkaloid. An internal standard was added and the alkaloids were separated using a 5 μm phenyl LC column with an ammonium acetate, glacial acetic acid, acetonitrile, and water mobile phase. Eight blind duplicates of dietary supplements or botanicals were analyzed by 10 collaborators. Included was a negative control, ephedra nevadensis, and negative controls fortified at 2 different levels with each of the 6 ephedrine-type alkaloids. The spike levels were approximately 100 and 1000 μg/g for NE, 100 and 600 μg/g for NPE, 6500 and 65 000 μg/g for E, 1000 and 10 000 μg/g for PE, 300 and 3000 μg/g for ME, and 100 and 1000 μg/g for MPE. On the basis of the accuracy and precision results for this interlaboratory study, it is recommended that this method be adopted Official First Action for the determination of 6 different individual ephedrine-type alkaloids in dietary supplements and botanicals.

Interlaboratory study of the benzylpenicillin by liquid chromatography

1996 ◽  
Vol 4 ◽  
pp. S169
Author(s):  
Zhu Yongxin ◽  
E. Roets ◽  
J.H. McB Miller ◽  
J.M. Spieser
Keyword(s):  
Liquid Chromatography ◽  
Interlaboratory Study
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