scholarly journals Toward a Harmonized and Standardized Protocol for the Determination of Total Hydroxytyrosol and Tyrosol Content in Virgin Olive Oil (VOO). The Pros of a Fit for the Purpose Ultra High Performance Liquid Chromatography (UHPLC) Procedure

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2429 ◽  
Author(s):  
Maria Z. Tsimidou ◽  
Nikolaos Nenadis ◽  
Aspasia Mastralexi ◽  
Maurizio Servili ◽  
Bojan Butinar ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Olive Oil ◽  
High Performance ◽  
Virgin Olive Oil ◽  
Method Comparison ◽  
Elution Time ◽  
Standardized Protocol ◽  
Liquid Chromatographic

Τoward a harmonized and standardized procedure for the determination of total hydroxytyrosol and tyrosol content in virgin olive oil (VOO), the pros of a recently published in house validated ultra high performance liquid chromatography (UHPLC) protocol are discussed comparatively with those of other procedures that determine directly or indirectly the compounds hosted under the health claim on “olive oil polyphenols” (EC regulation 432/2012). Authentic VOOs were analyzed with five different liquid chromatographic separation protocols and 1H-NMR one in five different laboratories with expertise in VOO phenol analysis within three months. Data comparison indicated differences in absolute values. Method comparison using appropriate tools (Passing-Bablok regression and Bland Altman analyses) for all protocols vs. the UHPLC one indicated slight or statistically significant differences. The results were also discussed in terms of cost effectiveness, detection means, standard requirements and ways to calculate the total hydroxytyrosol and tyrosol content. Findings point out that the in-house validated fit for the purpose UHPLC protocol presents certain pros that should be exploited by the interested parties. These are the simplicity of sample preparation, fast elution time that increase the number of samples analyzed per day and integration of well-resolved peaks with the aid of only two commercially available external standards. Importance of correction factors in the calculations is stressed.

Liquid-chromatographic determination of 4-hydroxyproline in urine.

1986 ◽  
Vol 32 (6) ◽  
pp. 1002-1004 ◽  
Author(s):  
H Hughes ◽  
L Hagen ◽  
R A Sutton
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Present Method ◽  
High Performance ◽  
Protein Hydrolysate ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract In this method for 4-hydroxyproline in urine, hydroxyproline is derivatized with 4-chloro-7-nitrobenzofurazan, with subsequent estimation by reversed-phase "high-performance" liquid chromatography. The ranges for excretion of free and total hydroxyproline while the subjects were ingesting unrestricted diets were 2-29 and 122-374 mumol/24 h (n = 21), respectively, with no significant sex-related difference. A comparison with results by colorimetry indicated no significant differences: mean (n = 18) concentrations (mumol/L) of hydroxyproline in urine were 180 (SD 149) by the present method, 163 (SD 166) by colorimetry. For protein hydrolysate the respective values were 5.9 (SD 2.7) and 6.7 (SD 2.9).

Simultaneous Liquid Chromatographic Determination of Thiabendazole, o-Phenylphenol, and Diphenyl Residues in Citrus Fruits, Without Prior Cleanup

1982 ◽  
Vol 65 (6) ◽  
pp. 1302-1304
Author(s):  
Yoshimi Kitada ◽  
Michiko Sasaki ◽  
Kaoru Tanigawa
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Citrus Fruits ◽  
Ultraviolet Detection ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple, rapid, efficient method has been developed for determining thiabendazole, o-phenylphenol, and diphenyl in citrus fruits by using high performance liquid chromatography, with fluorescence or ultraviolet detection. The compounds are extracted with ethyl acetate and separated from soluble fruit components on a LiChrosorb RP-8 column. Recovery of these compounds added to citrus fruits at 5 or 50 ppm levels was >93%; the limit of detection for the compounds is 1 ppm.

scholarly journals In House Validated UHPLC Protocol for the Determination of the Total Hydroxytyrosol and Tyrosol Content in Virgin Olive Oil Fit for the Purpose of the Health Claim Introduced by the EC Regulation 432/2012 for “Olive Oil Polyphenols”

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1044 ◽  
Author(s):  
Maria Tsimidou ◽  
Michaela Sotiroglou ◽  
Aspasia Mastralexi ◽  
Nikolaos Nenadis ◽  
Diego García-González ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Olive Oil ◽  
High Performance ◽  
Virgin Olive Oil ◽  
Cost Effective ◽  
Health Claim ◽  
Relative Standard ◽  
Oil Sector ◽  
Hydrolysis Conditions

An ongoing challenge in olive oil analytics is the development of a reliable procedure that can draw the consensus of all interested parties regarding the quantification of concentrations above the required minimum value of 5 mg of bioactive “olive oil polyphenols” per 20 g of the oil, to fulfill the health claim introduced by the European Commission (EC) Regulation 432/2012. An in-house validated ultra-high performance liquid chromatography (UHPLC) protocol fit for this purpose is proposed. It relies on quantification of the total hydroxytyrsol (Htyr) and tyrosol (Tyr) content in the virgin olive oil (VOO) polar fraction (PF) before and after acidic hydrolysis of their bound forms. PF extraction and hydrolysis conditions were as previously reported. The chromatographic run lasts ~1/3 of the time needed under high performance liquid chromatography (HPLC) conditions, this was also examined. Eluent consumption for the same piece of information was 6-fold less. Apart from being cost effective, a larger number of samples can be analyzed daily with less environmental impact. Two external curves, detection at 280 nm and correction factors for molecular weight difference are proposed. The method, which is fit for purpose, is selective, robust with satisfactory precision (percentage relative standard deviation (%RSD) values < 11%) and recoveries higher than 87.6% for the target analytes (Htyr, Tyr). Standard operational procedures are easy to apply in the olive oil sector.

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