scholarly journals Internal standard versus external standard calibration: an uncertainty case study of a liquid chromatography analysis

Química Nova ◽  
2010 ◽  
Vol 33 (4) ◽  
pp. 984-987 ◽  
Author(s):  
Elcio Cruz de Oliveira ◽  
Edson I. Muller ◽  
Fernanda Abad ◽  
Juliana Dallarosa ◽  
Cristine Adriano
Keyword(s):  
Liquid Chromatography ◽  
Internal Standard ◽  
Chromatography Analysis ◽  
External Standard ◽  
Standard Calibration

High Performance Liquid Chromatography Determination of Fentin Acetate Residue in Beet and Soil

2012 ◽  
Vol 550-553 ◽  
pp. 1173-1176
Author(s):  
Hui Qing Sun ◽  
Yi Qiang Li ◽  
Guang Jun Xu ◽  
Xiao Zhen ◽  
Jin Li Xu ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Detectable Level ◽  
Relative Standard ◽  
External Standard ◽  
Detectable Concentration ◽  
Acid Aqueous Solution ◽  
Standard Calibration

Abstract. [Aims] A high performance liquid chromatography (HPLC) was presented for determination of fentin acetate residue in beet and soils. [Methods] Fentin acetate was extracted from beet plants and soils with hydrochloric acid and acetonitrile, followed by a second extraction in dichloromethane, purified by acid aluminium oxide with methanol eluting, then dissolved by concentration and dilution with acetoneitrile. A HPLC with UV detection at 220 nm and a Waters Sun FireTM-C18 column, which was eluted with methanol and 0.5% phosphoric acid aqueous solution and was used based on an external standard calibration curve. [Results] The results showed that the average recoveries were 88.4-95.6% for beet plants and 91.2-91.8% for soils. The relative standard deviations were 2.0-4.5% and 4.3-5.3% respectively. The minimum detectable level was 1.6×10-10g, the lowest detectable concentration was 0.02mg/kg. [Conclusions] The method is convenient and can meet the requirement of residual analysis and also provide reference for other crops.

Simultaneous quantification of oxcarbazepine and its active metabolite in spiked human plasma using ultra performance liquid chromatography–MS/MS

Bioanalysis ◽  
2021 ◽  
Author(s):  
Karthik Rajendran ◽  
Bhadram Kalyan Chekraverthy ◽  
Rajendran Sankham Devendran ◽  
R Jasmin Sajini ◽  
Krishnaveni Nagappan
Keyword(s):  
Liquid Chromatography ◽  
Human Plasma ◽  
Multiple Reaction Monitoring ◽  
Internal Standard ◽  
Ultra Performance Liquid Chromatography ◽  
Simultaneous Estimation ◽  
Internal Standard Method ◽  
Formulation Development ◽  
Chromatography Analysis ◽  
New Formulation

Aim: Clinical monitoring of oxcarbazepine (OXC) and its metabolite licarbazepine (MHD) in biological matrix requires a sensitive and validated analytical method. The aim of this study is to develop and validate an optimized ultra performance liquid chromatography–MS/MS based bioanalytical method for the simultaneous estimation of OXC and its metabolite MHD in human plasma, using deuterated internal standard method. Materials & methods: A reverse phase ultra performance liquid chromatography analysis and mass spectrometric detection was performed using electrospray ionization in positive ion mode as interface, multiple reaction monitoring as mode of acquisition. Results & conclusion: The linearity range was 10–4011 ng/ml for OXC and 40–16061 ng/ml for MHD. The kinetic parameters were calculated and compared for bioequivalence. This method fulfilled the validation guidelines, could be employed for determining bioavailability and in new formulation development studies.

Rapid High-Performance Liquid Chromatography Analysis of Biogenic Amines in Fermented Vegetable Brines

1997 ◽  
Vol 60 (4) ◽  
pp. 414-419 ◽  
Author(s):  
D. HORNERO-MÉNDEZ ◽  
A. GARRIDO-FERNÁNDEZ
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Biogenic Amines ◽  
High Performance ◽  
Internal Standard ◽  
Acid Decarboxylase ◽  
Decarboxylase Activity ◽  
Amino Acid Decarboxylase ◽  
Chromatography Analysis ◽  
Vegetable Products

The presence of biogenic amines in fermented vegetable products is rare, although abnormal fermentation processes may lead to the growth of microorganisms and the amino acid decarboxylase activity that can produce them. Simple methods for the determination of such amines will help considerably in their control. A methodology for the analysis of biogenic amines in fermented vegetable brines has been developed. By means of benzoyl derivatization, nine biogenic amines, namely tryptamine, β-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, spermine, and agmatine could be analyzed by reverse-phase high-performance liquid chromatography (HPLC) in only 13 min. Quantification was achieved by using 1,8-diamineoctane as internal standard. The method consists basically of treating a precleaned sample with benzoyl chloride, as derivatizating reagent, in a strongly alkaline medium. The benzoylamine derivatives are extracted with diethyl ether, and after evaporation the residue is redissolved in methanol and analyzed by HPLC. By using UV-visible spectrophometric detection at both 225 and 254 nm, detection limits between 5.60 and 54.40 pg were achieved. The method appears to be applicable to a wide variety of brine samples, such as those from green table olives, cucumbers, and lupine.

Analysis for salicylic acid in serum by high-performance liquid chromatography.

1978 ◽  
Vol 24 (9) ◽  
pp. 1543-1544 ◽  
Author(s):  
D Blair ◽  
B H Rumack ◽  
R G Peterson
Keyword(s):  
High Performance Liquid Chromatography ◽  
Salicylic Acid ◽  
Liquid Chromatography ◽  
High Performance ◽  
Standard Procedure ◽  
Internal Standard ◽  
Peak Height ◽  
Fluorometric Method ◽  
External Standard ◽  
Methoxybenzoic Acid

Abstract We report a specific and sensitive quantitative assay for salicylate in serum or plasma. As little as 3 microliter of sample can be analyzed by an external standard procedure and larger volumes by diluting with the internal standard (o-methoxybenzoic acid). No extraction or derivatization is necessary and salicylic acid and the internal standard elute in 6 and 3.75 min, respectively. Peak-height ratios are linearly related to concentrations between 10 and 500 mg/liter. By comparison with an existing fluorometric method, our procedure is faster, more specific, and more sensitive.

Accurate fully automated powder diffraction data using zero-background sample holders

1994 ◽  
Vol 9 (3) ◽  
pp. 172-179 ◽  
Author(s):  
S. T. Misture ◽  
L. R. Chatfield ◽  
R. L. Snyder
Keyword(s):  
Standard Method ◽  
Internal Standard ◽  
Standard Technique ◽  
Calibration Method ◽  
Internal Standard Method ◽  
Absorption Coefficients ◽  
Calibration Methods ◽  
Wide Range ◽  
External Standard ◽  
Standard Calibration

An increasingly frequent used sample holder, the zero-background holder (ZBH), is evaluated for use in external standard calibration of powder patterns. The effectiveness of the ZBH calibration method is determined by comparison to the conventional internal- and external-standard calibration techniques. The three calibration methods are compared using the results of lattice parameter refinements of test powders, using Si as the standard. Several test materials were used in the evaluation which cover a wide range of absorption coefficients so sample transparency effects can be distinguished from sample displacement effects. Results of the calibrations clearly indicate that the ZBH method gives precision and accuracy comparable to the internal-standard method, and significantly better than the external-standard technique. In addition, the ZBH method yields substantially better results than the internal-standard method for materials with low absorption coefficients. Low-angle calibrations are also made on a ZBH using a proposed standard, silver behenate, which has peaks from 1.5° to 20° 2θ. These calibrations have shown that if care is not taken to establish a monolayer of powder on the ZBH crystal, significant errors in refined lattice parameters will result.

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