scholarly journals Reduction of chloride matrix effect using silver oxide as a precipitating reagent for the determination of trace anions in chloride-rich samplesviaion chromatography

2007 ◽  
Vol 30 (5) ◽  
pp. 693-698 ◽  
Author(s):  
Fu Houtun ◽  
Huang John Chuncheng ◽  
Zhao Limin ◽  
Chen Fang
Keyword(s):  
Matrix Effect ◽  
Silver Oxide ◽  
Chloride Matrix

Determination of acephate and methamidophos in tissues: appearance of matrix effect in gas chromatography–mass spectrometry

2011 ◽  
Vol 29 (2) ◽  
pp. 159-162 ◽  
Author(s):  
Nobuyuki Adachi ◽  
Hiroshi Kinoshita ◽  
Minori Nishiguchi ◽  
Motonori Takahashi ◽  
Harumi Ouchi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Matrix Effect ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry

Microsized Graphite Sensors for Potentiometric Determination of Cyclobenzaprine Hydrochloride in Pure Powder, Tablets, and Plasma

2011 ◽  
Vol 94 (6) ◽  
pp. 1807-1814 ◽  
Author(s):  
Nesrin K Ramadan ◽  
Hala E Zaazaa ◽  
Hanan A Merey
Keyword(s):  
Polyvinyl Chloride ◽  
International Union ◽  
Electroactive Material ◽  
Significant Difference ◽  
Intact Drug ◽  
Sensitivity And Selectivity ◽  
Ph Range ◽  
The U.S ◽  
Chloride Matrix

Abstract Two cyclobenzaprine hydrochloride (CZ) microsized graphite selective sensors were investigated with dibutylsebacate as a plasticizer in a polymeric matrix of carboxylated polyvinyl chloride (PVC-COOH) in the case of sensor 1, based on the interaction between the drug and the dissociated COOH groups in the PVC-COOH. Sensor 2 was based on the interaction between the drug and ammonium reineckate, which acted as anionic electroactive material in the presence of polyvinyl chloride matrix. The two sensors were constructed by using 2-hydroxy propyl β-cyclodextrin as an ionophore, which has a significant influence on increasing the membrane sensitivity and selectivity of both sensors. Fast and stable Nernstian responses of 1 × 10–5–1 × 10–2 and 1 × 10m–4–1 × 10–2 M for the two sensors, respectively, with slopes of 58.6 and 55.5 mV/decade, respectively, over the pH range 2–4 were obtained. The proposed method displayed useful analytical characteristics for determination of CZ in its pure powder form with average recoveries 99.95 ± 0.23 and 99.61 ± 0.34% for sensors 1 and 2, respectively, and in plasma with good recoveries. The sensors were also used to determine the intact drug in the presence of its degradate and, thus, could be used as stability-indicating methods. The obtained results by the proposed methods were statistically analyzed and compared with those obtained by the U.S. Pharmacopeia method; no significant difference for either accuracy or precision was observed. Results obtained with the two electrodes revealed their performance characteristics, which were evaluated according to International Union of Pure and Applied Chemistry recommendations.

scholarly journals Determination of adulterants in whey protein food supplements by liquid chromatography coupled to Orbitrap high resolution mass spectrometry

2019 ◽  
Vol 22 ◽  
Author(s):  
Rafaela Rocha Roiffé ◽  
Vinicius Figueiredo Sardela ◽  
Antônio Luís dos Santos Lima ◽  
Daniely Silva Oliveira ◽  
Francisco Radler de Aquino Neto ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
High Resolution ◽  
Whey Protein ◽  
Matrix Effect ◽  
High Resolution Mass Spectrometry ◽  
Food Supplements ◽  
Protein Food ◽  
Resolution Mass

Abstract Liquid chromatography coupled to Orbitrap high resolution mass spectrometry was shown to be an adequate technique to control the adulteration of whey protein food supplements with prohibited substances, not declared on the labels. An extraction method combined with an instrumental analysis that allowed for the determination of 105 substances in whey protein food supplements, was established. The pre-treatment of the samples consisted of protein precipitation and solid-phase extraction using weak cation exchange functionalized polymeric sorbent cartridges. The samples were directly analyzed by LC-Orbitrap-HRMS. The selectivity, limit of detection, repeatability, recovery, carryover and matrix effect were estimated as the validation parameters. The repeatability obtained was 96.19% and the recovery 83.80%, but carryover and the matrix effect were not observed. The present method was successfully applied to the analysis of commercial samples, verifying adulteration by diuretics (conivaptan and politiazide) and a stimulant (benfluorex) in seven of the eleven brands evaluated.

scholarly journals Simultaneous Determination of Twenty Mycotoxins in the Korean Soybean Paste Doenjang by LC-MS/MS with Immunoaffinity Cleanup

Toxins ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 594 ◽  
Author(s):  
So Young Woo ◽  
So Young Ryu ◽  
Fei Tian ◽  
Sang Yoo Lee ◽  
Su Been Park ◽  
...  
Keyword(s):  
Measurement Uncertainty ◽  
Simultaneous Determination ◽  
Ochratoxin A ◽  
Matrix Effect ◽  
Contamination Level ◽  
Immunoaffinity Column ◽  
Good Linearity ◽  
Soybean Paste ◽  
Contamination Levels

Doenjang, a Korean fermented soybean paste, is vulnerable to contamination by mycotoxins because it is directly exposed to environmental microbiota during fermentation. A method that simultaneously determines 20 mycotoxins in doenjang, including aflatoxins (AFs), ochratoxin A (OTA), zearalenone (ZEN), and fumonisins (FBs) with an immunoaffinity column cleanup was optimized and validated in doenjang using LC-MS/MS. The method showed good performance in the analysis of 20 mycotoxins in doenjang with good linearity (R2 > 0.999), intra- and inter-day precision (<16%), recovery (72–112%), matrix effect (87–104%), and measurement uncertainty (<42%). The validated method was applied to investigate mycotoxin contamination levels in commercial and homemade doenjang. The mycotoxins that frequently contaminated doenjang were AFs, OTA, ZEN, and FBs and the average contamination level and number of co-occurring mycotoxins in homemade doenjang were higher than those in commercially produced doenjang.

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