scholarly journals Determination of Vitamin K1 in Medical Foods by Liquid Chromatography with Postcolumn Reduction and Fluorometric Detection

2000 ◽  
Vol 83 (4) ◽  
pp. 957-962 ◽  
Author(s):  
George M Ware ◽  
G William Chase ◽  
Ronald R Eitenmiller ◽  
Austin R Long
Keyword(s):  
Limit Of Detection ◽  
Solid Phase ◽  
Sodium Bicarbonate Solution ◽  
Reversed Phase ◽  
Mean Value ◽  
Fluorometric Detection ◽  
Vitamin K1 ◽  
Limit Of Quantitation ◽  
Medical Foods

Abstract A liquid chromatographic (LC) method is described for the determination of vitamin K1 in medical foods. The sample is enzymatically digested with lipase and α-amylase and extracted with 1% sodium bicarbonate solution–isopropanol (1 + 1). After C18 solid-phase extraction, vitamin K1 is separated by nonaqueous reversed-phase LC, converted to the hydroquinone by postcolumn zinc reduction, and quantitated by fluorescence detection. The limit of detection is 8 pg (3 σ), and the limit of quantitation is 27 pg (10 σ) on column. Linear response ranged from 0.1 to 1.0 ng vitamin K1 (r = 0.9999). The mean recovery (n = 38) for all spiking levels was 101.6 ± 2.85%. Analysis of Standard Reference Material 1846, Infant Formula, gave a mean value of 0.95 ± 0.088 mg vitamin K/kg (K or K1?)(n = 31) with a coefficient of variation of 9.26.

scholarly journals Accelerated Solvent Extraction of Vitamin K1 in Medical Foods in Conjunction with Matrix Solid-Phase Dispersion

2000 ◽  
Vol 83 (2) ◽  
pp. 407-410 ◽  
Author(s):  
G William Chase ◽  
Brian Thompson
Keyword(s):  
Solvent Extraction ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Reversed Phase ◽  
Accelerated Solvent Extraction ◽  
Vitamin K1 ◽  
Matrix Solid Phase Dispersion ◽  
Phase Dispersion ◽  
Limit Of Quantitation ◽  
Medical Foods

Abstract An extraction technique is described for vitamin K1 in medical foods, using accelerated solvent extraction (ASE) in conjunction with matrix solid-phase dispersion (MSPD). The medical food sample is treated as it would be with MSPD extraction, followed by ASE for a hands-free automated extraction. The vitamin K1 in the ASE extract is then quantitated by reversed-phase liquid chromatography with fluorescence detection. The chromatography specifications are identical to those in previous work that used MSPD only, with a limit of detection of 6.6 pg and a limit of quantitation of 22 pg on column. Recoveries, which were determined for an analyte-fortified zero control reference material for medical foods, averaged 97.6% (n = 25) for vitamin K1. The method provides a rapid, automatic, specific, and easily controlled assay for vitamin K1 in fortified medical foods with minimal solvent usage.

scholarly journals Liquid Chromatographic Analysis of Vitamin K1 in Milk-Based Infant Formula with Matrix Solid-Phase Dispersion

1999 ◽  
Vol 82 (5) ◽  
pp. 1140-1145 ◽  
Author(s):  
G William Chase ◽  
Ronald R Eitenmiller ◽  
Austin R Long
Keyword(s):  
Infant Formula ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Reversed Phase ◽  
Vitamin K1 ◽  
Matrix Solid Phase Dispersion ◽  
Phase Dispersion ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method for vitamin K1 in milk-based infant formula is described. The vitamins are extracted from infant formula by matrix solid-phase dispersion and quantitated by reversed-phase chromatography with fluorescence detection. Vitamin K1 is converted to the fluorescent hydroquinone with a postcolumn zinc reductive reactor. The limit of detection is 12 pg, and the limit of quantitation is 38 pg on-column. Linear responses were obtained in the range 0.55-22.1 ng/mL (r2 = 0.9998). Recoveries of vitamin K1 from an analyte-fortified blank material for milk-based infant formula averaged 91.7% (n = 25). The method provides a rapid, specific, and easily controlled assay for vitamin K1 in fortified infant formula.

Liquid Chromatographic Method for Rapid Determination of Total Avermectin B1 and 8,9-Z-Avermectin B1 Residues in Apples

1995 ◽  
Vol 78 (2) ◽  
pp. 419-422 ◽  
Author(s):  
Janice A Cobin ◽  
Nelson A Johnson
Keyword(s):  
Chromatographic Method ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Rapid Determination ◽  
Reversed Phase ◽  
Extraction Column ◽  
Liquid Chromatographic Method ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method has been developed and validated for the rapid determination of avermectin B1 and 8,9-Z-avermectin B1 residues in apples. The avermectins are extracted from the crop matrix with an acetonitrile–water–hexane mixture; the extract is cleaned up on an aminopropyl solid-phase extraction column. The avermectins are derivatized with trifluoroacetic anhydride and analyzed by reversed-phase liquid chromatography with fluorescence detection. Recoveries of avermectins from apples fortified with about 2–77 ppb avermectin B1a or 2-27 ppb 8,9-Z-avermectin B1a averaged 85%. The limit of quantitation is 2 ppb (signal- to-noise [S/N] ratio, 12) and the limit of detection is 1 ppb (S/N ratio, 6) for each analyte. The assay is a simple, rapid, and sensitive method for monitoring the total amount of avermectin residues in apples.

scholarly journals Determination of Total Avermectin B1 and 8,9-Z-Avermectin B1 Residues in Wine by Liquid Chromatography

1996 ◽  
Vol 79 (5) ◽  
pp. 1158-1161 ◽  
Author(s):  
Janice A Cobin ◽  
Nelson A Johnson
Keyword(s):  
Liquid Chromatography ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Reversed Phase ◽  
Liquid Chromatographic Method ◽  
Limit Of Quantitation ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method was developed and validated for determination of avermectin Bi and 8,9-Z-avermectin B1 residues in wine. The sample is extracted with hexane-acetonitrile and the hexane layer containing the avermectins is concentrated/ purified on an aminopropyl solid-phase extraction (SPE) column. The purified extract is derivatized with trifluoroacetic anhydride and the derivatized avermectins are analyzed by reversed-phase liquid chromatography with fluorescence detection. Recoveries of avermectins from wine fortified with approximately 1-25 ng/g avermectin B1a or 8,9-Zavermectin B1a averaged 88 and 102%, respectively. The limit of quantitation is 1 ng/g (signal-to-noise ratio [S/N] > 10) and the limit of detection is 0.5 ng/g (S/N > 3) for each analyte. This procedure provides a simple, rapid, and sensitive method for monitoring the total amount of avermectin residues in wine.

scholarly journals Preparative Method for Isolating α-Zearalenol and Zearalenone Using Extracting Disk

1999 ◽  
Vol 82 (1) ◽  
pp. 90-94 ◽  
Author(s):  
George M Ware ◽  
Yuhong Zhao ◽  
Shia S Kuan ◽  
Allen S Carman
Keyword(s):  
Limit Of Detection ◽  
Solid Phase ◽  
Control Sample ◽  
Preparative Method ◽  
Reversed Phase ◽  
Fluorescence Detector ◽  
Coefficients Of Variation ◽  
Limit Of Quantitation ◽  
Standard Calibration ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method is described for the determination of zearalenol and zearalenone in corn. Zearalenol and zearalenone are extracted from corn with methanol–water (1+1) and cleaned up using a solid-phase extraction (SPE) disk, separatedon a reversed-phase analytical column, and detected with a fluorescence detector. The SPE disk concentrated and cleanly separated zearalenol and zearalenone from sample interferences. Standard calibration curves for zearalenol and zearalenone for the concentration range 25–500 ng/mL were linear. The small extract disk had a column capacity equivalent to 1 g extracted corn. Zearalenol and zearalenone were added at levels ranging from 10 to 2000 ng/g to a control sample that contained no detectable levels of zearalenol and zearalenone. Both toxins were recovered from spiked samples at 106.3 and 103.8%, with coefficients of variation of 7.6 and 13.0%, respectively. The method has an estimated reliable limit of detection and limit of quantitation around 10 and 40 ng/g for each toxin, respectively.

scholarly journals Determination of 7B3 Residues in Cotton Plants by Liquid Chromatography/Mass Spectrometry

2009 ◽  
Vol 92 (1) ◽  
pp. 302-306 ◽  
Author(s):  
Xiao-Jing Yan ◽  
Xiao-Mei Liang ◽  
Yan-Jun Xu ◽  
Shu-Hui Jin ◽  
Dao-Quan Wang
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Limit Of Detection ◽  
Reversed Phase ◽  
Liquid Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Relative Standard ◽  
Limit Of Quantitation ◽  
Cotton Plants

Abstract A method was developed for the determination of 7B3 (12-propyloxyimino-1,15-pentadecanlactam), a novel macrolactam fungicide, by liquid chromatography/mass spectrometry (LC/MS) with positive electrospray ionization (ESI+). The method used a reversed-phase C18 column and acetonitrilewater (60 + 40, v/v) mobile phase. The quick, easy, cheap, effective, rugged, and safe method was used for extraction of 7B3 from cotton plants, which involved the extraction of 10 g homogenized sample with 10 mL acetonitrile, followed by the addition of 4 g anhydrous MgSO4 and 1.0 g NaCl. After centrifugation, 1 mL of the buffered acetonitrile extract was transferred into a tube containing 50 mg primary secondary amine sorbent and 100 mg anhydrous MgSO4. After shaking and centrifugation, the final extract was transferred to an autosampler vial for concurrent analysis by LC/MS. The results of 7B3 determined by LC/MS in the selective ion monitoring mode were linear, and the matrix effect of the method was evaluated. The average recoveries of 7B3 fortified at different levels were within 84.1100.2, and the relative standard deviations were <7.5 for all samples analyzed. The method limit of detection and the limit of quantitation values were 0.03 and 0.1 mg/kg, respectively. The proposed method was successfully applied to determine 7B3 residues in practical samples. This method is sensitive, accurate, reliable, simple, and safe.

Detection of trace amounts of abamectin used as an antiparasitic agent in fallow deer tissues

2009 ◽  
Vol 57 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Diana Žele ◽  
Silvestra Kobal ◽  
Gorazd Vengušt ◽  
Andrej Bidovec ◽  
Anton Vengušt ◽  
...  
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Fallow Deer ◽  
Reversed Phase ◽  
Fat Tissue ◽  
Matrix Interference ◽  
Solid Phase Extraction Cartridge ◽  
Tissue Matrix

A sensitive and reliable method for the determination of trace amounts of abamectin in muscles, kidneys and fat tissue of fallow deer is presented. Abamectin was extracted from the tissues with acetonitrile and the extract was cleaned up on a C8 solid-phase extraction cartridge. Abamectin residue was derivatised with trifluoroacetic acid anhydride and 1-methylimidazole, and determined using reversed- phase high-performance liquid chromatography under isocratic conditions and fluorescence detection. The recoveries of the method were high and consistent, ranging from 78% to 90%. The limit of detection of the method was below 1 μg/kg when analysing muscle, kidney and fat tissue. Matrix-matched calibration was used in order to obtain accurate values and to avoid matrix interference.

scholarly journals Application of Packed-nanofibers Solid-phase Extraction for Determination of Rhodamine B in Sausage

2019 ◽  
Vol 8 (1) ◽  
pp. 17-21
Author(s):  
Lanlan Wei ◽  
Jianjun Deng ◽  
Tao Kang ◽  
Xuejun Kang
Keyword(s):  
Rhodamine B ◽  
High Performance ◽  
Orthophosphoric Acid ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Volume Ratio ◽  
Standard Curve ◽  
Relative Standard ◽  
Limit Of Quantitation

A method for the determination of Rhodamine B in sausage was developed and validated. After extraction of Rhodamine B with acetonitrile from foodstuffs, a novel electrospun polymer nanofibers packed micro-column was used for cleaning and concentrating of the analyte in the sample. High performance liquid chromatography with fluorescence detection (HPLC-Flu) was used for the determination of Rhodamine B in the sample. The mobile phase was composed of 3.0 g L-1 phosphate buffer and methanol (3:7, volume ratio), and the pH was adjusted to 7. 0 with orthophosphoric acid. The results showed that the standard curve was linear over the validated concentrations range of 2-500 ng g-1, and the limit of detection (LOD) and the limit of quantitation (LOQ) for Rhodamine B spiked samples was 0. 2 ng g-1 and 0. 7 ng g-1, respectively. The average recoveries of Rhodamine B were 90.4% -94.3% for sausage, and the relative standard deviation of the method was from 1.7% to 3.8%. This proposed method was applied to real sample, and there was no Rhodamine B found in sausage.

scholarly journals Development and validation of a SPE-UHPLC-fluorescence method for the analysis of ochratoxin-a in certain Turkish wines

2019 ◽  
Vol 38 (2) ◽  
pp. 161
Author(s):  
Elif Mine Oncu Kaya
Keyword(s):  
Ochratoxin A ◽  
Mobile Phase ◽  
High Performance ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Internal Standard ◽  
Fluorescence Method ◽  
Limit Of Quantitation ◽  
Development And Validation

A sensitive Ultra-High Performance Liquid Chromatography (UHPLC)-fluorescence method was developed and validated for the determination of ochratoxin-A (OTA) in Turkish wine samples. Naphthalene was used as an internal standard in this study. OTA was separated on a C18 (3.0 mm × 100 mm × 1.8 µm) column and analyses were run under isocratic conditions, with a mobile phase consisting of water/acetonitrile/acetic acid (50:50:1, v/v/v). The flow rate and injection volume were 0.5 ml min−1 and 10 μl, respectively. The excitation and emission wavelengths were 330 nm and 460 nm for OTA, respectively, and 220 nm and 325 nm for internal standard, respectively. A solid-phase extraction (SPE) clean-up procedure on a C18 cartridge was used prior to the analysis of the wine samples by UHPLC. The developed method was validated with respect to linearity, precision, accuracy, limit of detection (LOD), limit of quantitation (LOQ), stability and robustness. The method presented good RSD (< 4 %) and recovery (102.6–105.2 %) values. The LOD and LOQ values were 0.01 ng ml–1 and 0.05 ng ml–1, respectively. All other parameters were acceptable. OTA amounts were found in the range of 2.72‒7.40 µg kg‒1 in the Turkish wine samples.

Liquid-chromatographic determination of vitamin K1 in plasma, with fluorometric detection.

1986 ◽  
Vol 32 (10) ◽  
pp. 1925-1929 ◽  
Author(s):  
Y Haroon ◽  
D S Bacon ◽  
J A Sadowski
Keyword(s):  
Limit Of Detection ◽  
Lipid Fraction ◽  
Internal Standard ◽  
Reversed Phase ◽  
Phase System ◽  
Fluorometric Detection ◽  
Vitamin K1 ◽  
Crude Lipid ◽  
Zinc Metal ◽  
Liquid Chromatographic

Abstract This assay for phylloquinone (vitamin K1) in plasma requires a single liquid-chromatographic step. Much smaller volumes of plasma (0.5-1.0 mL) are required than in previous assays. Before liquid chromatography, we purified crude lipid extracts by conventional chromatography on silica, then extracted the lipid fraction by dissolving it in an acidic mixture of hexane/acetonitrile (1/4 by vol) containing 70 mmol of zinc chloride per liter. The vitamin K1 was selectively extracted into acetonitrile after being converted to vitamin K1 hydroquinone by addition of zinc metal. This procedure removes greater than 99% of contaminating lipids. We injected the lipid extract directly onto a reversed-phase column after re-converting the vitamin K1 hydroquinone to vitamin K1. Vitamin K1 was quantified by comparison with the internal standard (dihydro-vitamin K1) and detected fluorometrically after post-column "on-line" reduction to the hydroquinone with zinc metal. The lower limit of detection for vitamin K1 in the final reversed-phase system was about 0.05 microgram/L plasma; CVs for replicates were less than 10%. The mean concentration of vitamin K1 in plasma from 22 healthy fasting adults was 0.55 (range 0.09-2.12) micrograms/L.

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