scholarly journals Determination of the total tryptophan in food by high performance liquid chromatography combined with enzyme hydrolysis

Author(s):  
Huyen Trang Luu Thi ◽  
Trang Vu Thi ◽  
Ngan Le Viet ◽  
◽  
◽  
...  

High performance liquid chromatography was applied for the determination of tryptophan in food. The sample was hydrolyzed in a duration from 16 to 24 hour by protease enzyme at 50 oC. The extract was separated on the C8 reversed phase column with mobile phase of NaH2PO4 50mM pH 2.3: Methanol (82:18; v/v). The linearity of the method was kept in the range of 0.5 - 50 mg/L. Limit of detection was found to be 4.6 mg/100g. Recovery was determined by standard addition method, giving values of recovery in the range of 97 - 103% and RSD (n = 6) in the range of 0.077 - 2.27%. Internal standard was used to reduce the errors in analysis process and good reproducibility.

Author(s):  
Muhammad Fawad Rasool ◽  
Umbreen Fatima Qureshi ◽  
Nazar Muhammad Ranjha ◽  
Imran Imran ◽  
Mouqadus Un Nisa ◽  
...  

AbstractTh accurate rapid, simple and selective reversed phase high performance liquid chromatography (RP-HPLC) has been established and validated for the determination of captopril (CAP). Chromatographic separation was accomplished using prepacked ODSI C18 column (250 mm × 4.6 mm with 5 μm particle size) in isocratic mode, with mobile phase consisting of water: acetonitrile (60:40 v/v), pH adjusted to 2.5 by using 85% orthophosphoric acid at a flow rate of 1 mL/min and UV detection was performed at 203 nm. RP-HPLC method used for the analysis of CAP in mobile phase and rabbit plasma was established and validated as per ICH-guidelines. It was carried out on a well-defined chromatographic peak of CAP was established with a retention time of 4.9 min and tailing factor of 1.871. The liquid–liquid extraction method was used for extraction of CAP from the plasma. Excellent linearity (R2 = 0.999) was shown over range 3.125–100 µg/mL with mean percentage recoveries ranges from 97 to 100.6%. Parameters of precision and accuracy of the developed method meet the established criteria. Intra and inter-day precision (% relative standard deviation) study was also performed which was less than 2% which indicate good reproducibility of the method. The limit of detection (LOD) and quantification for the CAP in plasma were 3.10 and 9.13 ng/mL respectively. The method was suitably validated and successfully applied to the determination of CAP in rabbit plasma samples.


2011 ◽  
Vol 140 ◽  
pp. 296-301 ◽  
Author(s):  
Cai Mei Wu ◽  
Hong Min Yuan ◽  
Gang Jia ◽  
Zhi Sheng Wang ◽  
Xiu Qun Wu

A reversed high performance liquid chromatography method was developed for the quantitative determination of mimosine and 2,3-DHP in leaves ofLeucaena Leucocephala. Mimosine and 2,3DHP were extracted using 0.1N HCl.The chromatograph conditions were investigated and optimized. The optimal HPLC conditions as follows: Agilent HC-C18 column (4.6×150mm,5μm) was used at 30°C. The method used a variable wavelength UV detector at 280nm, the mobile phase consisted of 0.2 % (w/v) orthophosphoric acid and methanol, the gradient elution was adopted. The injection volume was 10μL. The linearity is favorable in the range of 1.0 to 50μg mL-1with a correlation coefficient of 0.99998 for mimosine and 0.99902 for 2,3DHP. Under the optimal conditions, the method limit of detection (LOD) of mimosine and 2,3DHP were 0.40mg/kg and 0.55mg/kg respectively. The recovery of mimosine was 87.00-94.70% with the RSD (n=5) of 2.75-3.81% in the spiked levels 0,1, 5, 20mg/g. At the same time, the recovery of 2,3DHP was 88-95.4% with the RSD (n=5) of 2.24-4.90%. The method was found to be simple, sensitive, fast and accurate, and has been applied successfully for the quantitative detection of mimosine and 2,3-DHP in leaves ofLeucaena Leucocephala, plasma and excretion of ruminant.


1990 ◽  
Vol 36 (8) ◽  
pp. 1436-1439 ◽  
Author(s):  
P Jatlow ◽  
H Nadim

Abstract We describe a procedure for measuring concentrations of cocaine in plasma by reversed-phase high-performance liquid chromatography, with ion-pairing. The procedure involves solvent extraction followed by back-extraction with dilute acid. The n-propyl ester of benzoylecgonine is used as an internal standard. An evaporation step is not required, and concentrations as low as 5 micrograms/L can be quantified. Plasma concentrations of cocaine determined by high-performance liquid chromatography correlated well with those determined by a previously reported gas-chromatographic procedure with nitrogen detection.


2019 ◽  
Vol 2 (3) ◽  
Author(s):  
Sang Li

To optimize the method for determination of Sucralose in drink by high performance liquid chromatography (HPLC). Using HPLC with RID, operating conditions were C18 reversed phase chromatograph column, 40:60 = methanol: 0.125% potassium hydrophosphate as mobil phase, measured at a flow rate of 0.8 mL/min. In the range of 20 ~ 400 mg L, with the concentration of Sucralose and corresponding peak area as standard, r = 0.9999, it has good correlation, the recovery of sucralose is 94~108%.The lower limit of detection of Sucralose was 0.0024 g/kg. This method not only meets the requirements of national standards, but also fast, sensitive, and environmentally friendly, improves the detection efficiency and safety of the detection of sucralose in drink by high performance liquid chromatography.


Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 609
Author(s):  
Elvira S. Plakidi ◽  
Niki C. Maragou ◽  
Marilena E. Dasenaki ◽  
Nikolaos C. Megoulas ◽  
Michael A. Koupparis ◽  
...  

Monitoring of biogenic amines in food is important for quality control, in terms of freshness evaluation and even more for food safety. A novel and cost-effective method was developed and validated for the determination of the main biogenic amines: histamine, putrescine, cadaverine, spermidine and spermine in fish tissues. The method includes extraction of amines with perchloric acid, pre-column derivatization with Pyrene Sulfonyl Chloride (PSCl), extraction of derivatives with toluene, back-dissolution in ACN after evaporation and determination by reversed phase high performance liquid chromatography with UV and intramolecular excimer fluorescence detection. The structure of the pyrene-derivatives was confirmed by liquid chromatography–mass spectrometry with electrospray ionization. The standard addition technique was applied for the quantitation due to significant matrix effect, while the use of 1,7-diaminoheptane as internal standard offered an additional confirmation tool for the identification of the analytes. Method repeatability expressed as %RSD ranged between 7.4–14% for the different amines and recovery ranged from 67% for histamine up to 114% for spermine. The limits of detection ranged between 0.1–1.4 mg kg−1 and the limits of quantification between 0.3–4.2 mg kg−1. The method was applied to canned fish samples and the concentrations of the individual biogenic amines were below the detection limit up to 40.1 mg kg−1, while their sum was within the range 4.1–49.6 mg kg−1.


Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5025
Author(s):  
Mena Ritota ◽  
Pamela Manzi

Tryptophan (TRP) is an essential amino acid which cannot be synthesized by humans and animals, but has to be supplied by exogenous sources, notably through the diet. The bulk of dietary TRP flows into the synthesis of body’s proteins, but the TRP metabolism also involves several biochemical reactions (i.e., serotonin and kynurenine pathways). Defects in the TRP transport mechanism or catabolism are related to a large number of clinical abnormalities. Therefore, dietary TRP intake is necessary not only for the body’s growth but also for most of the body’s metabolic functions. Among protein-based foods, milk proteins provide a relatively high amount of TRP. In this paper, a rapid chromatographic method for TRP determination in yoghurt, by ultra high performance liquid chromatography on a reversed-phase column with fluorescence detection (280 nm Ex; 360 nm Em), is provided. A linear gradient elution of acetonitrile in water allowed TRP analysis in 8.0 min. The limit of detection and limit of quantification of the method were 0.011 ng/µL and 0.029 ng/µL, respectively, using 5-methyl-l-tryptophan as the internal standard. The analytical method was successfully applied to commercial yoghurts from different animal species, and the TRP values ranged between 35.19 and 121.97 mg/100 g (goat and cow Greek type yoghurt, respectively).


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Cristina Megías ◽  
Isabel Cortés-Giraldo ◽  
Julio Girón-Calle ◽  
Javier Vioque ◽  
Manuel Alaiz

A method for determination ofβ-cyano-L-alanine,γ-glutamyl-β-cyano-L-alanine and other free amino acids inVicia sativais presented. Seed extracts were derivatized by reaction with diethyl ethoxymethylenemalonate and analyzed by reverse-phase high-performance liquid chromatography. Calibration curves showed very good linearity of the response. The limit of detection and quantification was 0.15 and 0.50 μM, respectively. The method has high intra- (RSD = 0.28–0.31%) and interrepeatability (RSD = 2.76–3.08%) and remarkable accuracy with a 99% recovery in spiked samples. The method is very easy to carry out and allows for ready analysis of large number of samples using very basic HPLC equipment because the derivatized samples are very stable and have very good chromatographic properties. The method has been applied to the determination ofγ-glutamyl-β-cyano-L-alanine,β-cyano-L-alanine, and common free amino acids in eight wild populations ofV. sativafrom southwestern Spain.


2013 ◽  
Vol 781-784 ◽  
pp. 903-907
Author(s):  
Dong Mei Huang ◽  
Jie Xu ◽  
Yong Fu Shi ◽  
Xuan Yun Huang ◽  
Huan Yu ◽  
...  

The method was established to detect fourteen sulfonamides residuces in Penaeus vannamei by high performance liquid chromatography coupled with post-column derivation. Sulfonamides residues were extracted with ethyl acetate after adding sulfapyridine as internal standard. The extract was concentrated.The residues were transferred to hydrochloric acid solution. The solution was defatted with n-hexane. The compounds were detected by HPLC with fluorescence detector .The standard addition method was used. The calibration curves were linear. The recoveries ranged from 77.8% to 103.6%. The relative standard deviations were all below 9.1%. Quantitative detection limits of fourteen sulfanomides ranged from1.0μg/kg to 5.0μg/kg. Results indicated that the method was easier, faster and more accurate.


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