Rapid, simple and simultaneous measurement of kynurenine and tryptophan in plasma by column switching-HPLC method

2007 ◽  
Vol 1304 ◽  
pp. 415-419 ◽  
Author(s):  
K. Kawai ◽  
H. Ishikawa ◽  
K. Ohashi ◽  
Y. Itoh ◽  
R. Teradaira
Keyword(s):  
Simultaneous Measurement ◽  
Column Switching ◽  
Hplc Method

A sensitive column-switching HPLC method for aripiprazole and dehydroaripiprazole and its application to human pharmacokinetic studies

2010 ◽  
Vol 33 (21) ◽  
pp. 3292-3298 ◽  
Author(s):  
Yumiko Akamine ◽  
Norio Yasui-Furukori ◽  
Midori Kojima ◽  
Yoshimasa Inoue ◽  
Tsukasa Uno
Keyword(s):  
Column Switching ◽  
Hplc Method ◽  
Pharmacokinetic Studies ◽  
Human Pharmacokinetic

Homocysteine and other thiols in plasma and urine: automated determination and sample stability

1993 ◽  
Vol 39 (2) ◽  
pp. 263-271 ◽  
Author(s):  
T Fiskerstrand ◽  
H Refsum ◽  
G Kvalheim ◽  
P M Ueland
Keyword(s):  
Column Switching ◽  
Fluorescence Yield ◽  
Reversed Phase ◽  
Hplc Method ◽  
Analytical Recovery ◽  
Single Column ◽  
Successful Separation ◽  
Heparin Plasma ◽  
Sampling Procedures ◽  
High Degree

Abstract We have developed a modified version of our fully automated column-switching HPLC method for determining total plasma homocysteine based on single-column (reversed-phase) separation. Homocysteine, cysteine, and cysteinylglycine in plasma (total concentrations), acid-precipitated plasma (non-protein-bound concentrations), and urine can be determined. The derivatization and chromatography were performed automatically by a sample processor. The successful separation of all thiol species (within 15 min) was accomplished by accurate adjustment of the pH of the mobile phase to 3.65 (plasma) or 3.50 (acid-precipitated plasma, urine). Maximal fluorescence yield of cysteine, cysteinylglycine, and, to a lesser degree, homocysteine was dependent on optimal concentrations of EDTA and dithioerythritol during reduction (with NaBH4) and derivatization (with monobromobimane). The method is sensitive (detection limit approximately 0.05 pmol) and has a high degree of precision (CV < 5%). The sample output is approximately 70 samples in 24 h. Serum and heparin plasma can also be analyzed. Hemolysis up to approximately 2.0 g/L of hemoglobin did not interfere with the analytical recovery of homocysteine or cysteine. Collection of blood, separation of plasma from whole blood, and acid precipitation must be standardized to obtain reproducible thiol results. Our modifications and the standardization of blood-sampling procedures have substantially improved the method and broadened its applications.

A sensitive semi-micro column HPLC method with peroxyoxalate chemiluminescence detection and column switching for determination of MDMA-related compounds in hair

2006 ◽  
Vol 387 (6) ◽  
pp. 1983-1990 ◽  
Author(s):  
Shinichi Nakamura ◽  
Mitsuhiro Wada ◽  
Brian L. Crabtree ◽  
Patricia M. Reeves ◽  
John H. Montgomery ◽  
...  
Keyword(s):  
Column Switching ◽  
Hplc Method ◽  
Chemiluminescence Detection ◽  
Peroxyoxalate Chemiluminescence ◽  
Related Compounds ◽  
Peroxyoxalate Chemiluminescence Detection

An Automated, Column-Switching HPLC Method for Analyzing Active and Excipient Materials in Both Cream and Ointment Formulations

1985 ◽  
Vol 11 (9-10) ◽  
pp. 1781-1796 ◽  
Author(s):  
Richard A. Kenley ◽  
Sharda Chaudhry ◽  
Gary C. Visor
Keyword(s):  
Column Switching ◽  
Hplc Method

Simple column-switching HPLC method for determining levels of the antifungal agent micafungin in human plasma and application to patient samples

2012 ◽  
Vol 27 (5) ◽  
pp. 551-555 ◽  
Author(s):  
Saori Nakagawa ◽  
Naoko Kuwabara ◽  
Hikaru Kobayashi ◽  
Sadahiko Shimoeda ◽  
Shin Ohta ◽  
...  
Keyword(s):  
Human Plasma ◽  
Antifungal Agent ◽  
Column Switching ◽  
Hplc Method ◽  
Simple Column

Non-extraction HPLC method for simultaneous measurement of dyphylline and doxofylline in serum

1990 ◽  
Vol 36 (1) ◽  
pp. 113-115 ◽  
Author(s):  
F Tagliaro ◽  
R Dorizzi ◽  
A Frigerio ◽  
M Marigo
Keyword(s):  
Simultaneous Measurement ◽  
Direct Injection ◽  
Internal Surface ◽  
Therapeutic Agents ◽  
Reversed Phase ◽  
Hplc Method ◽  
Chronic Obstructive ◽  
Standard Curve ◽  
Airway Diseases ◽  
Obstructive Airway Diseases

Abstract A direct injection HPLC method for the simultaneous measurement of dyphylline and doxofylline in serum is reported. Chromatography is carried out with a "Pinkerton" internal surface reversed-phase column and phosphate buffer (0.1 mol/L, pH 6.8) as mobile phase. Absorbance at 275 nm is monitored. Only 10 microL of serum is required to detect less than 1 mg of each drug per liter in biological samples. The standard curve for the method is linear over the range 6-100 mg/L, and precision is acceptable for both drugs, with CVs of 2% and 1.5% for respective concentrations of 6.2 and 25 mg/L. None of the 76 drugs tested for interference affected the measurement of either drug. Four samples can be injected per hour. This method provides a fast, accurate way to monitor two interesting therapeutic agents used in chronic obstructive airway diseases.

Development of an HPLC-Method for the Determination of E-2-Nonenal in Beer using Column Switching Techniques

1986 ◽  
Vol 25 (1-3) ◽  
pp. 67-79 ◽  
Author(s):  
L. C. Verhagen ◽  
J. Strating ◽  
U. R. Tjaden
Keyword(s):  
Column Switching ◽  
Hplc Method

A Convenient HPLC Method for Detection of Okadaic Acid Analogs as 9-Anthrylmethyl Esters with Automated Sample Cleanup by Column Switching

2014 ◽  
Vol 97 (2) ◽  
pp. 391-397 ◽  
Author(s):  
Hajime Uchida ◽  
Ryuichi Watanabe ◽  
Ryoji Matsushima ◽  
Naoyuki Uchida ◽  
Hiroshi Nagai ◽  
...  
Keyword(s):  
Okadaic Acid ◽  
Column Switching ◽  
Hplc Method

scholarly journals Non-Extraction HPLC Method for the Simultaneous Measurement of Theophylline and Caffeine in Human Serum

1989 ◽  
Vol 26 (6) ◽  
pp. 527-532 ◽  
Author(s):  
Sandra J Rainbow ◽  
Christine M Dawson ◽  
T R Tickner
Keyword(s):  
Human Serum ◽  
Correlation Coefficient ◽  
Simultaneous Measurement ◽  
Hplc Method ◽  
Therapeutic Monitoring ◽  
Serum Theophylline ◽  
Premature Neonates

A non extraction HPLC method is described for the simultaneous measurement of theophylline and caffeine in human serum using a Pinkerton™ ISRP column and u.v. detection at 275 nm. The method is suitable for therapeutic monitoring of theophylline levels in adults and, in particular, quantitation of both theophylline and caffeine in premature neonates where as little as 10 µL of sample can be used. Comparison of theophylline levels obtained by this method with EMIT analysis show a correlation coefficient of 0·97 ( n = 37) in adults and 0·79 ( n = 16) in premature neonates. There was no correlation between serum theophylline and caffeine levels in premature neonates receiving theophylline therapy. No interference was encountered from endogenous plasma components or other drugs in the 53 patients studied. Precision of the assays compares well with reported values for extraction HPLC and immunochemical analyses.

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