Development and Evaluation of a High-Speed Continuous-Flow Analyzer

1972 ◽  
Vol 18 (9) ◽  
pp. 1013-1018
Author(s):  
M A Evenson ◽  
M A Olson

Abstract A high-speed, high-performance, continuous-flow analyzer is described that operates at two to three times the usual analysis rate without necessitating corrections of the raw data and with no decrease in accuracy or precision. At faster speeds (180-300 samples/h) inductive sample interaction (%Ii), opposite in direction to carry-over, is for the first time quantitatively measured. A correction equation for %Ii was developed, and when it is applied to raw data, the accuracy of the results are significantly improved. Operating characteristics of the high-speed analyzer are described and the desirability of automatic computer corrections is discussed for the high-speed system.

Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 224
Author(s):  
Guang-Lei Zuo ◽  
Hyun Yong Kim ◽  
Yanymee N. Guillen Quispe ◽  
Zhi-Qiang Wang ◽  
Seung Hwan Hwang ◽  
...  

Muehlenbeckia volcanica (Benth.) Endl. (M. volcanica), native to South America, is a traditional Peruvian medicinal plant that has multi-therapeutic properties; however, no phytochemicals have been identified from it yet. In this study, a five-step polarity-stepwise elution counter-current chromatography (CCC) was developed using methanol/water (1:5, v/v) as the stationary phase and different ratios of n-hexane, ethyl acetate, and n-butanol as mobile phases to separate the compounds from the 70% methanol extract of M. volcanica, by which six compounds with a wide range of polarities were separated in a single run of CCC and were identified as gallic acid, protocatechuic acid, 4,4′-dihydroxy-3,3′-imino-di-benzoic acid, rutin, quercitrin, and quercetin. Then, two compounds from the fractions of stepwise elution CCC were separated using conventional high-speed CCC, pH-zone-refining CCC, and preparative high-performance liquid chromatography, and identified as shikimic acid and miquelianin. These compounds are reported from M. volcanica for the first time. Notably, except for shikimic acid, all other compounds showed anti-diabetic potentials via antioxidant, antiglycation, and aldose reductase inhibition. The results suggest that the polarity-stepwise elution CCC can be used to efficiently separate or fractionate compounds with a wide range of polarities from natural products. Moreover, M. volcanica and its bioactive compounds are potent anti-diabetic agents.


Author(s):  
Ming-yuan Cao ◽  
Ju-wu Hu ◽  
Zhen Gu ◽  
Wei Xiong ◽  
Lei Wu ◽  
...  

Abstract Four caffeoylquinic acid derivatives from the Gunura procumbens flowers (GPF) were successfully isolated and purified by high-speed counter-current chromatography (HSCCC). Ethyl acetate–methanol–water (3:1:3, v/v/v) was the optimum biphasic solvent system, which was selected by high-performance liquid chromatography (HPLC) and run on a preparative scale where the lower aqueous phase was used as the mobile phase with a head-to-tail elution mode. Chlorogenic acid (3.83 mg), Isochlorogenic acid A (6.51 mg), Isochlorogenic acid B (4.38 mg) and Isochlorogenic acid C (4.47 mg) were obtained for the first time in an one-step HSCCC separation from 800 mg of the crude extracts. The purities of four compounds were determined to be >95% by HPLC. Chemical structures of each isolated compounds were identified by nuclear magnetic resonance and electrospray ionization mass spectrometry methods. It is worth noting that all the four compounds were isolated here for the first time from GPF and this work confirms the effectiveness of HSCCC for the separation of compounds contained in complex samples, and provides a foundation for further exploitation of G. procumbens.


1975 ◽  
Vol 21 (6) ◽  
pp. 762-765 ◽  
Author(s):  
Jorge Lizana ◽  
Lennart Jansson ◽  
Kristoffer Hellsing

Abstract We describe a high-speed immunonephelometric continuous-flow system. The mechanical timing assembly and cams of the sampler were replaced by an external electronic control unit. Improved sampling precision, speeds of 2 to 900 samples per hour, and a wide variety of sample-to-wash ratios are the most important advantages of the unit. We analyzed albumin and fibrinogen at speeds of 150, 180, and 210 samples per hour. Carry-over studies showed that, in clinical practice, it should be possible to run the system at 150 samples per hour with an interaction of less than 5% and a precision (CV) of around 4%. Comparative studies with a previously described method, run at 60 samples per hour, showed correlation coefficients of 0.968 and 0.935 for albumin and fibrinogen, respectively. The electronic control unit can be used to increase speed and improve sampling precision of any continuous-flow system. An immunonephelometric system equipped with this device provided fast and reliable results, and required less antiserum than other systems described.


Author(s):  
Sven-Hendrik Voss ◽  
Michael Schueler ◽  
Michael Baerwolff ◽  
Markus Kranz ◽  
Sebastian Dressler

Marine Drugs ◽  
2018 ◽  
Vol 16 (10) ◽  
pp. 391 ◽  
Author(s):  
Yashu Chen ◽  
Qin Mu ◽  
Kai Hu ◽  
Mo Chen ◽  
Jifang Yang ◽  
...  

Menaquinone (MK) has an important role in human metabolism as an essential vitamin (VK2), which is mainly produced through the fermentation of microorganisms. MK8(H2) was identified to be the main menaquinone from Rhodococcus sp. B7740, a bacterium isolated from the arctic ocean. In this work, MK8(H2) (purity: 99.75%) was collected through a convenient and economic extraction process followed by high-speed countercurrent chromatography (HSCCC) purification. Additionally, high-resolution mass spectrometry (HRMS) was performed for further identification and the hydrogenation position of MK8(H2) (terminal unit) was determined using nuclear magnetic resonance (NMR) for the first time. MK8(H2) showed a superior antioxidant effect and antiglycation capacity compared with ubiquinone Q10 and MK4. High-performance liquid chromatography–mass spectrometer (HPLC-MS/MS) and molecular docking showed the fine interaction between MK8(H2) with methylglyoxal (MGO) and bull serum albumin (BSA), respectively. These properties make MK8(H2) a promising natural active ingredient with future food and medicine applications.


Author(s):  
Adham Raeisi ◽  
Mostafa Ramezani ◽  
Hossein Ravazadeh ◽  
Mahdi A. Taher

Introduction: Antibiotics analysis is performed by many methods such as spectrophotometry, fluorimetry, polarography, and high-performance liquid chromatography. This analysis doesn't require derivatization but requires expensive equipment and extensive preparation. When more than one antibiotic is present in a formulation, interactions may occur between the drugs that must be separated before measurement. Thin-layer chromatography is a useful technique for identifying antibiotics because of the low cost, high speed, and low servicing. Silica gel adsorbents have often been used as adsorbents in all thin-layer chromatography studies. In this study, zeolite was used as an adsorbent in thin- layer chromatography with high selectivity. Materials and Methods: The chromatographic behaviour of amoxicillin, ampicillin, cefazolin, cefixime, ceftriaxone, cefalexin, and penicillin was studied for the first time on a thin layer of zeolite with mobile, organic, and organic- organic phases. Discussion: The best separation of ceftriaxone from amoxicillin, ampicillin, cefazolin, cefixolin, cefalexin, and penicillin on a thin layer of zeolite using methanol as the mobile phase. The distance and rise time are 12 cm and 110 minutes, respectively. Conclusion: The results of the present study showed that using the current method, the selectivity of one antibiotic from other components as well as two-component andthree-component adsorption was obtained. Quantitative identification of antibiotics was also performed in multicomponent mixtures after selection of appropriate isolates.


Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.


Author(s):  
Marc H. Peeters ◽  
Max T. Otten

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.


Author(s):  
M. T. Postek ◽  
A. E. Vladar

One of the major advancements applied to scanning electron microscopy (SEM) during the past 10 years has been the development and application of digital imaging technology. Advancements in technology, notably the availability of less expensive, high-density memory chips and the development of high speed analog-to-digital converters, mass storage and high performance central processing units have fostered this revolution. Today, most modern SEM instruments have digital electronics as a standard feature. These instruments, generally have 8 bit or 256 gray levels with, at least, 512 × 512 pixel density operating at TV rate. In addition, current slow-scan commercial frame-grabber cards, directly applicable to the SEM, can have upwards of 12-14 bit lateral resolution permitting image acquisition at 4096 × 4096 resolution or greater. The two major categories of SEM systems to which digital technology have been applied are:In the analog SEM system the scan generator is normally operated in an analog manner and the image is displayed in an analog or "slow scan" mode.


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