Rapid Sample Analysis Research Articles

An HPLC-DAD method for rapid and high resolution analysis of concentrated BTEX and styrene aqueous samples

A rapid HPLC-DAD method for analysis of concentrated BTEX and styrene (BTEXS) aqueous mixtures is reported. Good resolutions of close to or greater than 1.5 were obtained for high equimolar BTEXS concentrations of up to 2.0 mM. At 5.5 min per sample analysis, this method is also one of the fastest HPLC methods to date, providing high throughput analysis and lowering the analysis price.

Sample preparation and direct electrospray ionization on a tip column for rapid mass spectrometry analysis of complex samples

A handheld pipette tip column electrospray ionization source (PTC-ESI source) was developed for rapid mass spectrometry analysis at ambient pressure. The PTC-ESI source was made up of three main component parts including a micro DC high voltage (HV) power supply, a micropipette and a disposable micropipette tip filled with a plug of adsorbent. A DC high voltage was applied to the sharp point of the micropipette tip column to induce electrospray ionization. The PTC-ESI source was successfully used for direct analysis of basic organic compounds, organic acids and peptides in a simple matrix. In the case of complex samples, micro-extraction based on the adsorbent phase filled in the pipette tip was used to remove impurities and concentrate target analytes prior to ionization. The eluting solution was not pipetted out, but directly dispersed in the form of electrospray from the pipette tip for ionization. The effectiveness of the PTC-ESI source has been further demonstrated by fast analysis of therapeutic compounds and endogenous bioactive chemicals in complex biological samples.

Development and validation of cleaning procedure of mixing equipment used for manufacturing ceftriaxone and Sulbactam injection tablet by using total organic carbon

–This paper presents a useful method using total organic carbon analyzers employing combustion for validating equipment cleaning procedures and verifying cleaning in a pharmaceutical plant. The study summarizes the initial steps that should be taken into account and focuses particularly on the solutions to some of the most critical considerations (e.g., detection and quantification limits, recovery). Also described are the calculation limits and the good results obtained. Cleaning validation is the process of assuring that cleaning procedures effectively remove the residue from manufacturing equipment/facilities below a predetermined level. This is necessary to assure the quality of future products using the equipment, to prevent cross-contamination, and as a World Health Organization Good Manufacturing Practices requirement. We have applied the Total Organic Carbon (TOC) analysis method to a number of pharmaceutical products. In this article we discuss the TOC method that we developed for measuring residual of sulbactam and ceftriaxone injection contain sulbactam (500mg) and ceftriaxone (1000mg) on surface of mixing tank during manufacturing process. Sulbactam contain 37.61%carbon and ceftriaxone contain 32.64% carbon The method with correlation coefficient R2 = 0.998 and method offers low detection capability (0.01ppm) and rapid sample analysis time. The accurate recovery values ranged from 96.46±1.92 with method precision less than 2%RSD of precision. We found that the TOC method is applicable for determining residual of sulbactam and ceftriaxone on pharmaceutical equipment surfaces and will be useful for cleaning validation. Keywords––Ceftriaxone, equipment surface (mixing tank), injection, sulbactam, Total Organic Carbon

Automatic sample changer for the analysis of powder samples on an X-ray single-crystal diffractometer equipped with an area detector

A low-budget automatic sample changer that allows the rapid analysis of powder or polycrystalline samples using an X-ray single-crystal diffractometer equipped with an area detector is here described. It uses control software that synchronizes the movement of a linear stage with the collection of frames by the diffractometer. Small pieces of thin solid samples are directly attached to a 30 cm ruler, which is used as a disposable magazine, while loose powder samples are loaded into holes on an acetate strip covered on both sides with Kapton tape and attached to the ruler. The use of this type of diffractometer with a sample changer is a simple, low cost and effective solution for studies requiring the analysis of a large number of samples by X-ray powder diffraction. With the current design up to 30 samples can be measured in a single experiment. The current sample changer was designed so that it can be fitted into a Bruker SMART APEX X-ray single-crystal diffractometer. However, it can be easily adapted to diffractometers from other makers.

Ultrasensitive Aptamer-Based Multiplexed Electrochemical Detection by Coupling Distinguishable Signal Tags with Catalytic Recycling of DNase I

This work reports an aptamer-based, disposable, and multiplexed sensing platform for simultaneous electrochemical determination of small molecules, employing adenosine triphosphate (ATP) and cocaine as the model target analytes. The multiplexed sensing strategy is based on target-induced release of distinguishable redox tag-conjugated aptamers from a magnetic graphene platform. The electronic signal of the aptasensors could be further amplified by coupling DNase I with catalytic recycling of self-produced reactants. The assay was based on the change in the current at the various peak potentials in the presence of the corresponding signal tags. Experimental results revealed that the multiplexed electrochemical aptasensor enabled the simultaneous monitoring of ATP and cocaine in a single run with wide working ranges and low detection limits (LODs: 0.1 pM for ATP and 1.5 pM for cocaine). This concept offers promise for rapid, simple, and cost-effective analysis of biological samples.

I Detected My Cancer with My Smart Phone

If Alexander Graham Bell were to come back to life and see what the telephone looks like today, compared with his own invention, he would definitely be astonished. It may not even be appropriate to call today's devices “telephones.” They are multitasking gadgets capable of a myriad of other operations. It is astonishing that the Apple iPhone claims over 350 000 specialized applications (better known as “apps”). On the basis of their multitasking capabilities, many have claimed that “smart phones” could have important applications in medicine, including the automatic transmission and sharing of laboratory data, images, and so forth in real time, for more effective patient care (1). In a recent issue of the journal Science Translational Medicine , Haun et al. described a micro–nuclear magnetic resonance (micro-NMR)5 device for the rapid molecular analysis of human tumor samples (2). In the editor's summary, the title was modified to read “A Micro-NMR Smart Phone for Detecting Cancer.” Unfortunately, the editor, in his effort to draw more attention, portrayed the smart phone as an integral part of this futuristic diagnostic device. In this case, however, the smart phone was only a minor player that merely controlled the NMR device, an operation that could probably be performed more conveniently with a remote control or a button on the NMR unit. Nevertheless, we describe this pioneering technology in an effort to realistically evaluate its usefulness and performance as the technology stands today. It is common in the diagnostic and biomarker field for advances like this one to be oversold and for overly optimistic views to be expressed regarding their clinical utility. The phenomenon of declining interest in published reports over time has become known as the “decline effect” (3). Some examples of oversold and subsequently failed cancer biomarkers have recently been discussed (4 …

Direct Ionization of Large Proteins and Protein Complexes by Desorption Electrospray Ionization-Mass Spectrometry

Desorption electrospray ionization-mass spectrometry (DESI-MS) has advantages for rapid sample analysis with little or no sample pretreatment, but performance for large biomolecules has not been demonstrated. In this study, liquid sample DESI, an extended version of DESI used for analysis of liquid samples, was shown to have capabilities for direct ionization of large noncovalent protein complexes (>45 kDa) and proteins (up to 150 kDa). Protein complex ions (e.g., superoxide dismutase, enolase, and hemoglobin) desorbed from solution by liquid sample DESI were measured intact, indicating the capability of DESI for preserving weak noncovalent interactions. Doping the DESI spray solvent with supercharging reagents resulted in protein complex ions having increased multiple charging without complex dissociation. Ion mobility measurements of model protein cytochrome c showed that the supercharging reagent favored the more compact conformation for the lower charged protein ions. Liquid sample DESI of hydrophobic peptide gramicidin D suggests that the ionization mechanism involves a droplet pick-up mixing process. Measurement of liquid samples significantly extends the mass range of DESI-MS, allowing the analysis of high-mass proteins such as 150 kDa immunoglobulin G (IgG) and thus represents the largest protein successfully ionized by DESI to date.

The CALUX bio-assay: Analytical comparison between mouse hepatoma cell lines with a low (H1L6.1c3) and high (H1L7.5c1) number of dioxin response elements

Dioxins, furans and polychlorinated biphenyls are contaminants of high concern and as such, sensitive tools are needed to detect these persistent organic compounds in a variety of matrices. Due to the large amount of samples that need to be investigated for example for food and feed control, the CALUX bioassay (H1L6.1 clone) was developed allowing rapid and cost-efficient analysis of biological and environmental samples. Recently, a new and more sensitive clone (H1L7.5) was constructed as the third generation CALUX bioassay. This new cell line was subject of an amplification of dioxin response elements (DREs), allowing lower concentrations of target compound to be analyzed. A comparison is made between the previous, well-defined H1L6.1c3 cell line and the new H1L7.5c1 cell line: it appears that the bioassay making use of the higher number of DREs is more stable and robust, shows better repeatability and reproducibility and is; on average, 3 times more sensitive.

Relationship between the Metabolite Profile and Technological Properties of Bovine Milk from Two Dairy Breeds Elucidated by NMR-Based Metabolomics

The aim of the present study was to investigate the relationship between the metabolite profile of milk and important technological properties by using nuclear magnetic resonance (NMR)-based metabolomics. The metabolomics approach was introduced for the metabolic profiling of a set of milk samples from two dairy breeds representing a wide span in coagulation properties. The milk metabolite profiles obtained by proton and carbon NMR spectroscopy could be correlated to breed and, more interestingly, also with the coagulation profile, as established by traditional methods by using principal component analysis (PCA). The metabolites responsible for the separation into breed could mainly be ascribed to carnitine and lactose, whereas the metabolites varying in the samples with respect to coagulation properties included citrate, choline, carnitine, and lactose. The results found in the present study demonstrated a promising potential of NMR-based metabolomics for a rapid analysis and classification of milk samples, both of which are useful for the dairy industry.

Comparison of direct antimicrobial susceptibility testing methods for rapid analysis of bronchial secretion samples in ventilator-associated pneumonia

Two hundred and fifty tracheal aspirates were subjected to direct antimicrobial susceptibility testing by disk diffusion, Etest and inoculation on antibiotic-enriched MacConkey agar plates. Results were compared with those obtained using an automated system on microorganisms recovered from standard quantitative culture. A total of 255 microorganisms were isolated from 194 positive samples by the standard quantitative procedure. A total of 85.1%, 82.5% and 72.5% agreement between direct disk diffusion, Etest and antibiotic-enriched MacConkey agar plates, respectively, and the standard procedure was observed in 64 microorganisms obtained from monomicrobial cultures that corresponded to 240 individual microorganism–antimicrobial agent combinations. Three (1.3%) and four (1.7%) very major errors for direct disk diffusion and Etest methods were observed, respectively. The antibiotic-enriched MacConkey agar plate method compared with the standard procedure demonstrated an unacceptable rate of very major (6.7%) and major errors (14.2%). Clinical evaluation of direct susceptibility tests based on the speculative impact on clinical practice by guiding patient's early treatment, if all positive cultures corresponded to infection, was correct in 79.9% for the direct disk diffusion test, 77.8% for the direct Etest method and 68.0% for antibiotic-enriched MacConkey agar plates. Direct diffusion tests (Etest or disk diffusion) applied on respiratory samples are rapid techniques that provide results comparable with standard antimicrobial susceptibility testing in <24 h.

Studies on the Element Characteristics of Nephrite Minerals from Different Deposits by GD-MS

Element characteristics of nephrite minerals were determined by glow discharge mass spectrometry (GD-MS) through surface adherence method. To solve the conductivity problem of non-conductive nephrite samples, high purity indium pin (>99.9999%) was used as discharge host. During the preparation procedure, a small piece of nephrite sample was ground into powder (about 200 meshes), and then the sample powder was coated on the surface of indium pin to form a rod sample. Typical elements of nephrite minerals were analyzed by GD-MS, and the relative standard deviations showed that the stability and reproducibility of this method were good. Meanwhile, four nephrite samples from two different deposits were further studied by this method. The GD-MS results of major elements and trace elements revealed that typical elements of the nephrite minerals from same deposit were similar, and those from different deposits exhibited significant difference. In addition, results of external-beam proton induced X-ray emission (PIXE) were consistent with the result of GD-MS determination. The present approach had been proven to be simple, efficient to perform the rapid screening and multi-element semi-quantitative analysis of nephrite samples.

Quantitative nmr spectroscopy for quality control of drugs and pharmaceuticals

Results of a comparative analysis of the use of quantitative NMR spectroscopy for the quality control of pharmaceuticals and drugs are presented. Diquertin, the active principle of which is the common flavonoid dihydroquercetin (taxifolin, 3,3′,4′,5,7-pentahydroxyflavanone), was used as an example. Quantitative 1H NMR spectroscopy can be recommended on the basis of this comparative analysis for use when it is necessary to identify all possible impurities or to confirm the absence of toxic contaminants and also for rapid analysis of samples.

A mussel tissue certified reference material for multiple phycotoxins. Part 1: design and preparation

The development of multi-analyte methods for lipophilic shellfish toxins based on liquid chromatography-mass spectrometry permits rapid screening and analysis of samples for a wide variety of toxins in a single run. Validated methods and appropriate certified reference materials (CRMs) are required to ensure accuracy of results. CRMs are essential for accurate instrument calibration, for assessing the complete analytical method from sample extraction to data analysis and for verifying trueness. However, CRMs have hitherto only been available for single toxin groups. Production of a CRM containing six major toxin groups was achieved through an international collaboration. Preparation of this material, CRM-FDMT1, drew on information from earlier studies as well as improved methods for isolation of toxins, handling bulk tissues and production of reference materials. Previous investigations of stabilisation techniques indicated freeze-drying to be a suitable procedure for preparation of shellfish toxin reference materials and applicable to a wide range of toxins. CRM-FDMT1 was initially prepared as a bulk wet tissue homogenate containing domoic acid, okadaic acid, dinophysistoxins, azaspiracids, pectenotoxin-2, yessotoxin and 13-desmethylspirolide C. The homogenate was then freeze-dried, milled and bottled in aliquots suitable for distribution and analysis. The moisture content and particle size distribution were measured, and determined to be appropriate. A preliminary toxin analysis of the final material showed a comprehensive toxin profile.

Determination of 235U/238U ratio by low energy gamma rays: an experimental evaluation

Abstract Determination of the 235U/238U atom ratio is required for various applications. Thermal ionization mass spectrometry (TIMS) is generally used for this purpose since the method gives most precise results. However, the method has limitations like elaborate sample preparation and high cost. Thus, an alternative methodology based on low energy photon spectrometry (LEPS) was developed and tested using routine samples. It involves the determination of gamma (γ) activity at gamma energies of 63.3, 92.8, 143.6, and 185.7 keV in isotopic standard solutions of uranium and different enriched uranium sample solutions. The method is fast as it does not involve chemical treatment as in TIMS. In this paper, a comparative evaluation of thermal ionization mass spectrometry and low energy photon spectrometry is reported for the determination of the 235U/238U atom ratio. The results obtained by the two systems compare well with each other within the statistical uncertainties of each system. Between the two, low energy photon spectrometry will be useful for rapid analysis of routine samples of enriched uranium.

Enrichment Cultivation of Beer-Spoiling Lactic Acid Bacteria

J. Inst. Brew. 117(3), 285–294, 2011 Various molecular methods have been developed for the rapid microbiological analysis of beer and brewing process samples. However, enrichment cultivation is still needed in order to reach the detection limits of the molecular assays, and it may directly contribute to the costs and accuracy of detection. The selection of proper enrichment cultivation conditions may be complex due to the wide variety of available media, and controversial reports of their performance. Therefore, this article aims to clarify this process by summarizing the main factors affecting the growth of lactic acid bacteria (LAB) in the enrichment cultures and reported media for this purpose.

A lab-on-a-chip for rapid blood separation and quantification of hematocrit and serum analytes

In this work, a new lab-on-a-chip for rapid analysis of low volume blood samples was designed, fabricated and demonstrated for integration of serum separation, hematocrit evaluation, and protein quantitation. Blood separation was achieved using microchannel flow-based separation. A novel method for evaluating hematocrit from microfluidic flow-separated blood samples was developed using gray scale analysis of a point-and-shoot digital photograph of separated blood in a micochannel. Protein quantitation was subsequently performed in a high surface area-to-volume ratio microfluidic chemiluminescent immunoassay using cell depleted serum produced by microfluidic flow-based separation of whole blood samples. All three steps were achieved in a single microchannel with separation of blood samples and hematocrit evaluation in less than 1 min, and protein quantitation in 5 min.

Detection of intermediates for the Eschweiler–Clarke reaction by liquid-phase reactive desorption electrospray ionization mass spectrometry

Desorption electrospray ionization mass spectrometry (DESI-MS) has been developed dramatically as a powerful tool for the rapid analysis of samples in their native environment. Here a novel application of DESI-MS was demonstrated for direct probing of the reactive intermediates in the liquid-phase Eschweiler-Clarke reaction, a reductive amination reaction whereby a primary (or secondary) amine is successively N-methylated using excess formaldehyde and formic acid. The intermediates ion species of sodiated amino alcohol ([I + Na](+)) and iminium ([II](+)), along with the corresponding protonated molecules of amine reactant ([M + H](+)) and end product ([III + H](+)), were simultaneously and unambiguously characterized by the positive ion DESI-MS in the native liquid-phase reactive condition. The operating variables were optimized for better analytical performance including the spray solvent composition (such as formic acid concentration, proportion of methanol-water), voltage applied, spray spatial distance and incident angle. The feasibility of the reactive DESI-MS detection of acid-formaldehyde methylations was further validated using amines of a large variety of chemical types (2 primary and 3 secondary amines). Thus, the liquid-phase reactive DESI-MS technique allows the direct analysis of reaction intermediates occurring in complex liquid solutions without sample preparation to provide a valuable insight into chemical reaction mechanisms.

Microfluidic Wheatstone bridge for rapid sample analysis

We developed a microfluidic analogue of the classic Wheatstone bridge circuit for automated, real-time sampling of solutions in a flow-through device format. We demonstrate precise control of flow rate and flow direction in the "bridge" microchannel using an on-chip membrane valve, which functions as an integrated "variable resistor". We implement an automated feedback control mechanism in order to dynamically adjust valve opening, thereby manipulating the pressure drop across the bridge and precisely controlling fluid flow in the bridge channel. At a critical valve opening, the flow in the bridge channel can be completely stopped by balancing the flow resistances in the Wheatstone bridge device, which facilitates rapid, on-demand fluid sampling in the bridge channel. In this article, we present the underlying mechanism for device operation and report key design parameters that determine device performance. Overall, the microfluidic Wheatstone bridge represents a new and versatile method for on-chip flow control and sample manipulation.

Rapid HPLC-UV method for quantification of l-citrulline in watermelon and its potential role on smooth muscle relaxation markers

A rapid and versatile HPLC-UV method for the separation and quantification of l-citrulline from watermelon was developed for the first time. Freeze dried juice and rind of watermelon were extracted with acidic methanol and analysed by HPLC using 0.03mM phosphoric acid as a mobile phase. The separation was performed using Zorbax SB-Aq, Synergi Hydro-RP and Gemini C-18 columns and l-citrulline was detected at 207nm. l-Citrulline was well separated using Gemini C-18 column and the identity of peak was confirmed by mass spectral analysis. These results were further confirmed by derivatisation method. The developed method was used for the quantification of l-citrulline in three varieties of watermelons such as Petite treat, Jamboree and Yellow crimson. Thus, the method is simple and involves direct analysis of aqueous extracts and can be used for rapid routine analysis of commercial samples. In addition, the role of watermelon extracts on smooth muscle relaxation markers was studied. Petite treat and Jamboree extracts induced production of nitric oxide (NO) significantly at 25ppm. This was also confirmed by measuring the change in the intracellular calcium. Additionally, extracts of petite treat rind and juice have shown inhibition of phosphodiesterase-5A (PDE-5A) in human uterine smooth muscle cells (UtSMC). The induction of NO and the inhibition of PDE-5A seems to suggest the potency of these extracts to induce relaxation of smooth muscle. It is possible that watermelon extracts may have the potential to induce PDE-5A mediated smooth muscle relaxation. However, further studies are critical before any conclusion of smooth muscle relaxation effect.

Real-time polymerase chain reaction followed by fast sequencing allows rapid genotyping of microbial pathogens

In this study we describe a novel protocol for rapid molecular analysis of patient samples using a combination of real-time polymerase chain reaction (PCR) and Sanger sequencing. This would normally take 2 working days in the diagnostic laboratory, but using this protocol the process can be completed within 3 h using equipment normally found in the laboratory. The innovative steps in this protocol are the sequencing of the product generated in the diagnostic real-time PCR, addition of a sequencing tail to the PCR primer, which increases the quality of the sequence without loss of sensitivity or specificity, and optimization of the hands-on and instrument steps using modern reagents. The read length of the sequencing step is routinely 250 nucleotides, which is substantially longer than existing rapid sequencing methods, increasing the chances of covering several genetic markers within 1 analysis. As proof of the concept, we used the detection and genotyping of the intestinal parasite Giardia lamblia, but the protocol can be applied to any PCR and sequence-based analysis.