نتایج جستجو برای: hplc apci
تعداد نتایج: 33470 فیلتر نتایج به سال:
Some cases of occurrence of matrix effects (mostly ion suppression) in protein-precipitated plasma samples, and their influence on the validity of plasma concentrations and pharmacokinetic parameters, are discussed. The comparison of matrix effects using either electrospray (TurboIonspray, TISP) or atmospheric pressure chemical ionization (APCI) indicated that APCI is less prone to matrix effec...
Real-time monitoring of benzene, toluene, ethylbenzene, and xylenes (BTEX) in ambient air is essential for the early warning detection associated with the release of these hazardous chemicals and in estimating the potential exposure risks to humans and the environment. We have developed a tandem mass spectrometry (MS/MS) method for continuous real-time determination of ambient trace levels of B...
Particulate matter with aerodynamic diameter ?2.5 ?m (PM 2.5 ) concentrations vary between countries similar carbon dioxide (CO 2 emissions, which can be partially explained by differences in air pollution control efficacy. However, no indicator of efficacy has yet been developed. We aimed to develop such an indicator, and evaluate its global temporal distribution association country-level heal...
از مهمترین متابولیتها در زعفران آپوکاروتنوئیدهای کروستین و کروسین می باشند. رنگ زعفران بطور عمده به میزان و کیفیت حضور ماده کروسین بستگی دارد که خود فرم استری گلیکوزیله شده ماده کروستین توسط آنزیم گلیکوزیل ترانسفراز می باشد. در این مطالعه به جداسازی و شناسایی این متابولیتها در عصاره متانولی و کلرفرمی کلاله زعفران در مرحله گرده افشانی با دستگاه کروماتوگرافی مایع مجهز به طیف سنجی جرمی (LC-APCI...
Esterified astaxanthins are used as functional nutraceuticals and pigments in many food products. Unfortunately, the utilization is currently limited due to their chemical instability and poor water-solubility. In this study, esterified astaxanthins were quantified and purified from Haematococcus pluvialis using a novel and precise approach. By HPLC-(+)APCI-MS/MS, twenty esterified astaxanthin ...
A new coating material was used for a stir bar sorptive extraction (SBSE) method coupled to a high throughput sample analysis technique. This allowed for a simple procedure for fast determinations of eight steroid hormones (estriol, estradiol, ethynylestradiol, estrone, progesterone, medroxyprogesterone, levonorgestrel, northindrone) in water. Sample pre-treatment was performed using an in-hous...
Pregnancy and post-partum represent a period of susceptibility for vitamin D insufficiency. This study investigated S-25 [OH] D levels in women in northern Sweden 4 weeks post-partum and its association with selected background factors. Blood from 100 healthy women were analyzed for iron status and serum levels of S-25[OH] D using ionization-mass spectrometry (HPLC-APCI-MS). ˂50 nmol/L was cate...
Introduction. Edible oils containing > 60 % monoenoic acids (i. e. oleic acid), in particular olive oil and Canola oil have been shown to exhibit beneficial effects on lipid metabolism in human (LDL-cholesterol blood levels, triacylglycerol blood levels) within the last few years [1]. These findings are in contrast to earlier recommandations by nutrition experts who strongly favored high-linole...
A Dielectric Barrier Discharge Ionization (DBDI) LC/MS interface is based on the use of a low-temperature helium plasma, which features the possibility of simultaneous ionization of species with a wide variety of physicochemical properties. In this work, the performance of LC/DBDI-MS for trace analysis of highly relevant species in food and environment has been examined. Over 75 relevant specie...
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