scholarly journals Determination of fomesafen and quizalofop-p-ethyl in beans using modified QuEChERS-HPLC-DAD

2020 ◽  
Vol 12 (3) ◽  
pp. 35-45
Author(s):  
Huacheng Tang ◽  
Jiangling Qu ◽  
Dongmei Cao ◽  
Weisong Wang ◽  
Yuhao Lou
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Diode Array ◽  
Diode Array Detection ◽  
Quechers Method ◽  
Modified Quechers ◽  
Relative Standard ◽  
Array Detection ◽  
Extraction Agent

An improved quick, easy, cheap, effective, rugged, and safe (QuEChERS) method combined with high-performance liquid chromatography (HPLC) coupled to diode array detection was established for the determination of fomesafen and quizalofop-p-ethyl in beans. It is simple and efficient and can be used in most laboratories. This method optimizes four chromatographic conditions, namely, mobile phase, mobile phase ratio, flow rate, and detection wavelength. The effects of extraction agent, extraction dose, extraction time, NaCl amount, and adsorbent on the pretreatment effect were studied. The recoveries were high (92.4–117.8%), and repeatability was good (relative standard deviation [RSD] ranged from 0.35 to 4.36%). The standard solutions ranged from 0.1 to 25 ?g/mL. The detection limits of fomesafen and quizalofop-p-ethyl were 0.005 and 0.003 mg/kg, respectively.

scholarly journals Determination of Nifedipine in Serum ofWomen in Preterm Labor by High-Performance Liquid Chromatography with Diode Array Detection

2006 ◽  
Vol 89 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Dorota Kowalczuk ◽  
Maria Bożena Wawrzycka ◽  
Agnieszka Haratym Maj
Keyword(s):  
Human Serum ◽  
Preterm Labor ◽  
Mobile Phase ◽  
High Performance ◽  
Solid Phase ◽  
Diode Array ◽  
Sublingual Administration ◽  
Diode Array Detection ◽  
Array Detection

Abstract Nifedipine (Nif) is widely used in treating cardiovascular disorders (especially hypertension) and for inhibiting preterm labor. A fully validated selective high-performance liquid chromatographic method with diode array detection, using solid-phase extraction, was developed for the determination of Nif in human serum. To assess specificity, Nif and its degradation products were separated on a Purospher RP-18 (5m, 125×4 mm) column plus a LiChrospher 100<sup/> RP-18 (5 μm, 4×4 mm) precolumn with a mobile phase of methanol10 mM aqueous trifluoroacetic acid, pH 7.3 (57 + 43, v/v); chromatographic separation was followed by UV detection at 238 nm. For toxicological analysis, Nif in the presence of other calcium-channel antagonist drugs was identified under optimum chromatographic conditions. The calibration graph was constructed over the concentration range of 12.5400 ng/mL in serum with good correlation (r 0.9956). This method was not subject to interference by other plasma components and was successfully applied to the assay of Nif in spiked human serum and in serum of women in preterm labor after sublingual administration of 30 mg Nif per day divided into 3 equal doses. The mean recovery based on the ratio of the slopes of serum and mobile phase standard curves was 96.5%. The detection and quantification limits of the drug in spiked human serum were found to be 6 and 17.5 ng/mL, respectively. Validation of the method demonstrated good intraday and interday precision, which ranged from 2.18 to 6.67% and from 6.52 to 11.93%, respectively.

scholarly journals Determination of polyphenols in beer by an effective method based on solid-phase extraction and high performance liquid chromatography with diode-array detection

2008 ◽  
Vol 25 (No. 4) ◽  
pp. 182-188 ◽  
Author(s):  
M. Dvořáková ◽  
P. Hulín ◽  
M. Karabín ◽  
P. Dostálek
Keyword(s):  
Solid Phase Extraction ◽  
High Performance ◽  
Solid Phase ◽  
Diode Array ◽  
Diode Array Detection ◽  
Phase Extraction ◽  
Spectrophotometric Detection ◽  
Relative Standard ◽  
Array Detection

The determination of polyphenols by spectrophotometric detection is complicated due to their low concentrations in beer. The beer samples have to be pre-concentrated before using the spectrophotometric detection for their quantification. An analytical method based on solid-phase extraction (SPE) and followed by high performance liquid chromatographic separation with diode-array detection is used for the determination of free gallic, protocatechuic, caffeic, p-coumaric, ferulic and salicylic acids, of (+)-catechin, (–)-epicatechin, and quercetin. These phenolic compounds participate in colloidal and sensory stability of beer. Six different SPE cartridges were tested and three different types of elution with the most appropriate solvents (acetonitrile, acetone and methanol) were used. The performance of the HPLC method was assessed by the evaluation of parameters such as absolute recovery, relative standard deviation (RSD – lower than 10%), the limit of quantification (LOQ), and the limit of detection (LOD). The polyphenol content in various types of Czech beer is presented.

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