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Anal Methods 2018 Sep 14;10(35):4339-4349. Epub 2018 Aug 14.

Mechanical and Aerospace Engineering, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.

Differential mobility spectrometry (DMS) based detectors require rapid data analysis capabilities, embedded into the devices to achieve the optimum detection capabiites as portable trace chemical detectors. Automated algorithm-based DMS dispersion plot data analysis method was applied for the first time to pre-process and separate 3-dimentional (3-D) DMS dispersion data. We previously demonstrated our AnalyzeIMS (AIMS) software was capable of analyzing complex gas chromatography differential mobility spectrometry (GC-DMS) data sets. Read More

Anal Methods 2018 Jul 26;10(27):3364-3374. Epub 2018 Jun 26.

Department of Chemistry, Saint Louis University.

Fabrication of microchip-based devices using 3-D printing technology offers a unique platform to create separate modules that can be put together when desired for analysis. A 3-D printed module approach offers various advantages such as file sharing and the ability to easily replace, customize, and modify the individual modules. Here, we describe the use of a modular approach to electrochemically detect the ATP-mediated release of nitric oxide (NO) from endothelial cells. Read More

Anal Methods 2018 Aug 30;10(32):4000-4006. Epub 2018 Jul 30.

Department of Chemistry and Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269, United States.

Low cost, miniaturized assay platforms that work with small sample volumes, high sensitivity and rapid detection will have high value in future biomolecular diagnostics. Herein we report an automated, 3D printed electrochemiluminescent (ECL) immunoarray integrated with a nanostructured pyrolytic graphite sheet (PGS) microwell chip configured to detect 2 proteins simultaneously from complex liquid samples with high sensitivity and selectivity. Assays are done in 18 min at cost of < $1. Read More

Anal Methods 2018 Sep 20;10(35):4264-4274. Epub 2018 Aug 20.

Department of Chemistry, University of Michigan, Ann Arbor, MI 48109.

We have developed droplet microfluidic devices in thermoplastics and demonstrated the integration of key functional components that not only facilitate droplet generation, but also include electric field-assisted reagent injection, droplet splitting, and magnetic field-assisted bead extraction. We manufactured devices in poly(methyl methacrylate) and cyclic olefin polymer using a hot-embossing procedure employing silicon masters fabricated via photolithography and deep reactive ion etching techniques. Device characterization showed robust fabrication with uniform feature transfer and good embossing yield. Read More

Anal Methods 2019 Jan 21;11(3):247-261. Epub 2018 Dec 21.

Dept. of Chemistry, University of Virginia, Charlottesville, VA 22901.

The carbon-fiber microelectrode has been used for decades as a neurotransmitter sensor. Recently, new strategies have been developed for making carbon electrodes, including using carbon nanomaterials or pyrolyzing photoresist etched by nanolithography or 3D printing. This review summarizes how chemical and 3D surface structures of new carbon electrodes are optimized for neurotransmitter detection. Read More

Anal Methods 2018 Dec;10(46):5455-5590

U.S. Environmental Protection Agency, Office of Research and Development, National Homeland, Security Research Center, Threat Consequence Assessment Division, 26 Martin Luther King Dr. W., Cincinnati, OH 45268.

Sodium fluoroacetate or Compound 1080 is a rodenticide registered in the United States for use in livestock protection collars. The collars are employed to control predation on herd animals (i.e. Read More

Anal Methods 2018 Jul 5;10(28):3436-3443. Epub 2018 Jun 5.

Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.

In this work, we expand upon our recently developed droplet-based sample chopping concepts by introducing a multiplexed fluidic micro-chopper device (μChopper). Six aqueous input channels were integrated with a single oil input, and each of these seven channels was controlled by a pneumatic valve for automated sampling through software control. This improved design, while maintaining high precision in valve-based droplet generation at bandwidths of 0. Read More

Anal Methods 2018 Jul 29;10(25):2972-2979. Epub 2018 May 29.

Department of Chemistry and Biochemistry, The Ohio State University, Columbus OH 43210, USA.

Amplification of long DNA segments with the highest possible specificity and lowest bias is one of the main goals of modern genomics. Quadruplex priming amplification (QPA) is a single-primer isothermal method, which employs the free energy of quadruplex structures as the driving force for DNA amplification without any extra reaction components. As a result, QPA represents one of the simplest isothermal assays and was previously shown to be suitable for amplification of relatively short DNA sequences. Read More

Anal Methods 2018 1;10:572-578. Epub 2018 Feb 1.

Division of Pharmaceutical Analysis, Center for Drug Evaluation and Research, Food and Drug Administration, St. Louis, MO, 63110, USA.

A mixture of α-cyano-4-hydroxycinnamic acid and 1,5-diaminonaphthalene was discovered as a novel binary matrix for the qualitative analysis of 14 small-molecule (~250-550 Da) cardiovascular drugs by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and MS/MS in either positive or negative ion mode. Read More

Anal Methods 2018 Apr 23;10(14):1618-1623. Epub 2018 Mar 23.

Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Matthews Ave., Urbana, IL 61801, USA.

Analysis methods based upon the quantitative, real-time polymerase chain reaction are extremely powerful; however, they face intrinsic limitations in terms of target multiplexing. In contrast, silicon photonic microring resonators represent a modularly multiplexable sensor array technology that is well-suited to the analysis of targeted biomarker panels. In this manuscript we employ an asymmetric polymerase chain reaction approach to selectively amplify copies of cDNAs generated from targeted miRNAs before multiplexed, label-free quantitation through hybridization to microring resonator arrays pre-functionalized with capture sequences. Read More

Anal Methods 2018 Jan 4;10(2):204-213. Epub 2017 Dec 4.

National Institute of Standards and Technology, Materials Measurement Science Division, Gaithersburg, MD, USA.

Trace explosives detection, a crucial component of many security screening environments, commonly employs wipe-sampling. Since collection of an explosive residue is necessary for detection, it is important to have a thorough understanding of the parameters that affect the efficiency of collection. Current wipe-sampling evaluation techniques for explosive particles have their limits: manual sampling (with fingers or a wand) is limited in its ability to isolate a single parameter and the TL-slip/peel tester is limited to a linear sample path. Read More

Anal Methods 2018 Jan 6;10(1):37-45. Epub 2017 Dec 6.

Department of Chemistry, Saint Louis University, 3501 Laclede Ave, St. Louis, MO 63103.

The ability to use microchip-based electrophoresis for fast, high-throughput separations provides researchers with a tool for close-to real time analysis of biological systems. While PDMS-based electrophoresis devices are popular, the separation efficiency is often an issue due to the hydrophobic nature of PDMS. In this study, a hybrid microfluidic capillary device was fabricated to utilize the positive features of PDMS along with the electrophoretic performance of fused silica. Read More

Anal Methods 2018 8;10(2):256-262. Epub 2017 Dec 8.

Ralph N Adams Institute for Bioanalytical Chemistry, Department of Chemistry, University of Kansas, Lawrence, Kansas-66047, United States.

The need to investigate the fragmentation of fucosylated glycopeptides is driven by recent work showing that at least one, and perhaps many, glycopeptide analysis scoring algorithms are less effective at identifying fucosylated glycopeptides than non-fucosylated glycopeptides. Herein, we study the CID fragmentation characteristics of fucosylated glycopeptides and the scoring rules of the glycopeptide analysis software, GlycoPep Grader, in an effort to improve automated assignments of these important glycopeptides. We identified some prominent product ions from a common fragmentation pathway of fucosylated glycopeptides that were not accounted for in the scoring rules. Read More

Anal Methods 2018 28;10(1):46-50. Epub 2017 Nov 28.

Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA.

The rapid release of new tobacco products requires high-throughput quantitative methods to support tobacco research. Sample preparation for LC-MS and GC-MS is time consuming and limits throughput. Paper spray tandem mass spectrometry (PS-MS/MS) is proposed and validated as a simple and rapid method for quantification of nicotine and cotinine in complex matrices to support tobacco-related research. Read More

Anal Methods 2018 18;10(1):22-29. Epub 2017 Oct 18.

Department of Biological Engineering, Utah State University, Logan, Utah 84322-4105, U.S.A.

G-protein-coupled receptor 120 (GPR120), as a member of the rhodopsin family of G-protein-coupled receptors, has been shown to function as a sensor for dietary fat in the gustatory and digestive systems. Its specific role in the chemoreception of fatty acids, which is thought to be crucial in understanding the mechanism surrounding the control of fat intake and, accordingly, in the treatment of obesity, remains unclear. Here we report a novel surface-enhanced Raman spectroscopy (SERS)-fluorescence bimodal microscopic technique for detection and imaging of GPR120 in single living cells. Read More

Anal Methods 2017 26;9(34):5058-5064. Epub 2017 Jun 26.

State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China.

Fungicides are widely used for growing the grapes that are used for making wines. Chromatography coupled with tandem mass spectrometry is usually time and labor consuming for quantitation of fungicides in wines. In this work, a simple ambient mass spectrometry method using paper capillary spray was developed for the fast quantitation of four pyrazole fungicides in wines. Read More

Anal Methods 2017 19;9(23):3464-3476. Epub 2017 Apr 19.

Inorganic & Radiation Analytical Toxicology Branch, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, Mailstop F-50, Atlanta, GA 30341-3717.

The Centers for Disease Control and Prevention developed a biomonitoring method to rapidly and accurately quantify chromium and cobalt in human whole blood by ICP-MS. Many metal-on-metal hip implants which contain significant amounts of chromium and cobalt are susceptible to metal degradation. This method is used to gather population data about chromium and cobalt exposure of the U. Read More

Anal Methods 2017 Aug 19;9(29):4261-4266. Epub 2017 Jun 19.

Department of Chemical Engineering, University of Louisville, Louisville, KY 40208.

The electronic cigarette (e-cigarette) has emerged as popular electronic nicotine delivery devices (ENDs). However, the general safety and validity of e-cigarettes for nicotine delivery efficacy are still not well understood. This study developed a new method for efficient measurement of nicotine levels in both the liquids (e-liquids) used in e-cigarettes and the aerosols generated from the e-cigarettes. Read More

Anal Methods 2017 16;9:3876-3883. Epub 2017 Jun 16.

Centers for Disease Control and Prevention, 4770 Buford Hwy, MS F44, Atlanta, GA 30341.

An automated dried blood spot (DBS) elution coupled with solid phase extraction and tandem mass spectrometric analysis for multiple fentanyl analogs was developed and assessed. This method confirms human exposures to fentanyl, sufentanil, carfentanil, alfentanil, lofentanil, α-methyl fentanyl, and 3-methyl fentanyl in blood with minimal sample volume and reduced shipping and storage costs. Seven fentanyl analogs were detected and quantitated from DBS made from venous blood. Read More

Anal Methods 2017 13;9(28):4112-4134. Epub 2017 Jun 13.

Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA.

Surface acoustic waves (SAWs), are electro-mechanical waves that form on the surface of piezoelectric crystals. Because they are easy to construct and operate, SAW devices have proven to be versatile and powerful platforms for either direct chemical sensing or for upstream microfluidic processing and sample preparation. This review summarizes recent advances in the development of SAW devices for chemical sensing and analysis. Read More

Anal Methods 2017 29;9(23):3418-3421. Epub 2017 May 29.

Department of Chemistry, Southern Methodist University, Dallas, TX 75275-0314, USA.

The metabolism of ethanol to acetaldehyde has been visualized in living lung epithelial cells using a hydrazinyl naphthalimide fluorescent probe. Utilizing a condensation reaction between carbonyls and a hydrazine moeity, we demonstrate that the fluorescent probe (Aldehydefluor-1) AF1 reacts with a range of reactive carbonyl species including formaldehyde, acetaldehyde, glyoxylic acid, and methyl glyoxal. With AF1, it is possible to directly visualize endogenous carbonyl metabolites. Read More

Anal Methods 2017 Jan 14;9(3):402-408. Epub 2016 Dec 14.

Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, Kansas.

Carnosine, a dipeptide found in a variety of tissues, is believed to possess antioxidant properties. It serves as a scavenger of reactive nitrogen and oxygen species (RNOS), which are important stress mediators of pro-inflammatory conditions and can lead to macrophage activation. In this study, intracellular concentrations of carnosine in murine RAW 264. Read More

Anal Methods 2017 Sep 9;9(34):4964-4970. Epub 2017 May 9.

Department of Chemistry, The George Washington University, Washington DC, 20052.

Single-cell mass spectrometry (MS) empowers the characterization of metabolomic changes as cells differentiate to different tissues during early embryogenesis. Using whole-cell dissection and capillary electrophoresis electrospray ionization (CE-ESI) MS, we recently uncovered metabolic cell-to-cell differences in the 8- and 16-cell embryo of the South African clawed frog (), raising the question whether metabolic cell heterogeneity is also detectable across the dorsal-ventral axis of the 8-cell embryo. Here, we tested this hypothesis directly in the live embryo by quantifying single-cell metabolism between the left dorsal-animal (D1L) and left ventral-animal (V1L) cell pairs in the same embryo using microprobe single-cell CE-ESI-MS in the positive ion mode. Read More

Anal Methods 2016 Oct 6;8(39):7260-7264. Epub 2016 Sep 6.

Molecular Science and Biomedicine Laboratory, State Key Laboratory for Chemo/Bio Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Collaborative Research Center of Molecular Engineering for Theranostics, Hunan University, Changsha 410082, China.

A promising biosensor for effectively lead (II) ion detection in practical applications was developed by constructing a Pb-specific L-DNAzyme, the enantiomer of the natural nucleic acid-constructed D-DNAzyme. This fluorescent sensor contains the L-enzyme strand with a quencher at the 3' end, and the L-substrate strand with a fluorophore at the 5' and a quencher at the 3' ends that formed a complex. In the presence of Pb, the L-substrate is cut into two fragments, leading to the recovery of fluorescence. Read More

Anal Methods 2017 Feb 4;9(5):847-855. Epub 2017 Jan 4.

The Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24061, US.

This study describes the development of a microfluidic biosensor called the iterative mechanical characteristics (iMECH) analyzer which enables label-free biomechanical profiling of individual cells for distinction between metastatic and non-metastatic human mammary cell lines. Previous results have demonstrated that pulsed mechanical nanoindentation can modulate the biomechanics of cells resulting in distinctly different biomechanical responses in metastatic and non-metastatic cell lines. The iMECH analyzer aims to move this concept into a microfluidic, clinically more relevant platform. Read More

Anal Methods 2017 Aug 26;9(29):4267-4274. Epub 2017 Jun 26.

National Institute of Standards and Technology, Gaithersburg, MD 20899.

A dietary supplement, kelp contains a significant amount of arsenic that is mostly arsenosugars. The determination of arsenosugars is difficult due to a lack of arsenosugar calibration standard, because arsenosugar compounds are not commercially available. This work reports the determination of arsenicals in a kelp extract with traceability to the International System of Units (SI). Read More

Anal Methods 2017 Jun 24;9(24):3579-3593. Epub 2017 May 24.

Department of Chemistry, Indiana University, Bloomington, IN 47405, USA.

Carbohydate purification remains a bottleneck in securing analytical standards from natural sources or by chemical or enzymatic synthesis. This review highlights the scope and remaining limitations of recent approaches and methods development in liquid chromatography for robust and higher-throughput carbohydrate separation and isolation. Read More

Anal Methods 2017 Jan 6;9(3):385-392. Epub 2016 Dec 6.

Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717.

Elucidation and monitoring of biomarkers continues to expand because of their medical value and potential to reduce healthcare costs. For example, biomarkers are used extensively to track physiology associated with drug addiction, disease progression, aging, and industrial processes. While longitudinal analyses are of great value from a biological or healthcare perspective, the cost associated with replicate analyses is preventing the expansion of frequent routine testing. Read More

Anal Methods 2017 Jun 21;9(22):3274-3283. Epub 2017 Apr 21.

Department of Chemistry, Saint Louis University.

Polymer nano/micro fibers have found many applications including 3D cell culture and the creation of wound dressings. The fibers can be produced by a variety of techniques that include electrospinning, the primary disadvantage of which include the requirement for a high voltage supply (which may cause issues such as polymer denaturation) and lack of portability. More recently, solution blow spinning, where a high velocity sheath gas is used instead of high voltage, has been used to generate polymer fibers. Read More

Anal Methods 2017 Apr 10;9(15):2275-2283. Epub 2017 Mar 10.

Department of Chemistry, University of Louisville, Louisville, KY 40292, United States.

Stable isotope assisted metabolomics (SIAM) uses stable isotope tracers to support studies of biochemical mechanisms. We report a suite of data analysis algorithms for automatic analysis of SIAM data acquired on a high resolution mass spectrometer. To increase the accuracy of isotopologue assignment, metabolites detected in the unlabeled samples were used as reference metabolites to generate possible isotopologue candidates for analysis of peaks detected in the labeled samples. Read More

Anal Methods 2016 Nov 30;8(43):7739-7746. Epub 2016 Sep 30.

Department of Chemistry and Biochemistry, Brigham Young University, Provo 84602, UT, USA.

On-chip preconcentration, purification, and fluorescent labeling are desirable sample preparation steps to achieve complete automation in integrated microfluidic systems. In this work, we developed electrokinetically operated microfluidic devices for solid-phase extraction and fluorescent labeling of preterm birth (PTB) biomarkers. Reversed-phase monoliths based on different acrylate monomers were photopolymerized in cyclic olefin copolymer microdevices and studied for the selective retention and elution of a fluorescent dye and PTB biomarkers. Read More

Anal Methods 2017 Jan 28;9(1):38-45. Epub 2016 Oct 28.

Department of Chemistry and Biochemistry, Florida State University, 95 Chieftain Way, Tallahassee, FL 32306.

Insulin secretion from islets of Langerhans is a dynamic process that is essential for maintaining glucose homeostasis. The ability to measure dynamic changes in insulin levels upon glucose stimulation from single islets will allow testing of therapeutics and investigating mechanisms of defective secretion observed in metabolic diseases. Most approaches to date for measurement of rapid changes in insulin levels rely on separations, making the assays difficult to translate to non-specialist laboratories. Read More

Anal Methods 2016 Dec 28;8(47):8272-8279. Epub 2016 Oct 28.

Rutgers University, Department of Biomedical Engineering, Piscataway, NJ, 08854, USA.

Centrifugal microfluidics has received much attention in the last decade for the automation of blood testing at the point-of-care, specifically for the detection of chemistries, proteins, and nucleic acids. However, the detection of common blood cells on-disc, particularly leukocytes, remains a challenge. In this paper, we present two analytical methods for enumerating leukocytes on a centrifugal platform using a custom-built fluorescent microscope, acridine orange nuclear staining, and image processing techniques. Read More

Anal Methods 2016 Oct 15;8(39):7002-7013. Epub 2016 Sep 15.

Ralph Adams Institute of Bioanalytical Chemistry, Department of Chemistry, University of Kansas.

Western blotting is a ubiquitous tool used extensively in the clinical and research settings to identify proteins and characterize their levels. It has rapidly become a mainstay in research laboratories due to its specificity, low cost, and ease of use. The specificity arises from the orthogonal processes used to identify proteins. Read More

Anal Methods 2017 Jan 22;9(4):609-617. Epub 2016 Dec 22.

Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.

The emerging stimulant drug of abuse (3,4)-methylenedioxypyrovalerone [()-MDPV] is self-administered as a racemic mixture by intranasal, iv, oral, and smoking routes. The individual enantiomers are known to have widely different pharmacological effects, with ()-MDPV showing much greater potency than ()-MDPV in pharmacological testing. The goal of these studies was to develop and validate an analytical method for quantitation of ()-MDPV, ()-MDPV and ()-MDPV in small volumes of rat serum using a chiral separation column and liquid chromatography-mass spectrometry. Read More

Anal Methods 2017 Feb 31;9(8):1229-1241. Epub 2017 Jan 31.

Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA.

Antimicrobial resistance (AMR) is recognized as a global threat to human health. Rapid detection and characterization of AMR is a critical component of most antibiotic stewardship programs. Methods based on amplification of nucleic acids for detection of AMR are generally faster than culture-based approaches but they still require several hours to more than a day due to the need for transporting the sample to a centralized laboratory, processing of sample, and sometimes DNA purification and concentration. Read More

Anal Methods 2017 Jan 9;9(4):724-728. Epub 2017 Jan 9.

Wuhan Yaogu Biotech, Ltd. Wuhan 430075, China; Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch St. Jackson, MS 39217, USA.

() is a natural product that has diverse nutritional and medicinal values. Since the availability of natural becomes limited its authentication and quality control is of high significance. Herein we report on profiling of metals in by using inductively coupled plasma mass spectrometry (ICP-MS). Read More

Anal Methods 2017 11;9(1):46-54. Epub 2016 Oct 11.

University of Minnesota, Department of Chemistry, 207 Pleasant Street SE, Minneapolis, MN, 55455-0431, United States.

We report the use of ultra high performance liquid chromatography (UPLC) coupled with acquisition of low- and high-collision energy mass spectra (MS) to explore small molecule compositions that are unique to either enriched-autophagosomes or secretions of chemically activated murine mast cells. Starting with thousands of features, each defined by a chromatographic retention time, values and ion intensities, manual examination of the extracted ion chromatograms (XIC) of chemometrically selected features was essential to eliminate false positives, occurring at rates of 33, 14 and 37% in samples of three biological systems. Forty-six percent of features that passed the XIC-based checkpoint, had IDs in compound databases used here. Read More

Anal Methods 2016 Oct 16;8(37):6696-6700. Epub 2016 Aug 16.

Department of Chemistry, Western Kentucky University, Bowling Green, KY 42101 USA.

Multiplexed detection of pathogen-specific DNA sequences in a simple and reliable way is in great demand for clinical and biomedical applications. However, there is still a lack of available DNA detection methods that are simple and pathogen-selective for point-of-care (POC) testing. Here, we report a novel zinc finger protein (ZFP)-based chemiluminescent method for direct detection of pathogenic double-stranded DNA (dsDNA) in a multiplexed platform. Read More

Anal Methods 2016 Jul 11;8(26):5190-5196. Epub 2016 May 11.

Department of Mechanical Engineering, Columbia University, New York, NY 10027, United States.

We present a microfluidic aptamer-based biosensor for detection of low-molecular-weight biomarkers in patient samples. Using a microfluidic device that integrates aptamer-based specific analyte extraction, isocratic elution, and detection by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, we demonstrate rapid, sensitive and label-free detection of arginine vasopressin (AVP) in human plasma ultrafiltrate. AVP molecules in complex matrices are specifically captured by an aptamer that is immobilized on microbeads via affinity binding in a microchamber. Read More

Anal Methods 2017 4;9(34):4988-4996. Epub 2017 May 4.

National Institute of Standards and Technology, Materials Measurement Science Division, Gaithersburg, MD, USA.

An ambient mass spectrometry (MS) platform coupling resistive Joule heating thermal desorption (JHTD) and direct analysis in real time (DART) was implemented for the analysis of inorganic nitrite, nitrate, chlorate, and perchlorate salts. The resistive heating component generated discrete and rapid heating ramps and elevated temperatures, up to approximately 400 °C s and 750 °C, by passing a few amperes of DC current through a nichrome wire. JHTD enhanced the utility and capabilities of traditional DART-MS for the trace detection of previously difficult to detect inorganic compounds. Read More

Anal Methods 2016 Aug 4;8(29):5806-5811. Epub 2016 Jul 4.

Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.

Polymeric quaternary ammonium salts (polyquaterniums) have found increasing use in industrial and cosmetic applications in recent years. More specifically, polyquaternium-10 (PQ-10) is routinely used in cosmetic applications as a conditioner in personal care product formulations. Herein, we demonstrate the use of potentiometric polyion-sensitive polymeric membrane-based electrodes to quantify PQ-10 levels. Read More

Anal Methods 2016 Apr 24;2016(16):3373-3382. Epub 2016 Mar 24.

National Physical Laboratory, Teddington, TW11 0LW, UK; School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK; School of Pharmacy, University of Nottingham, Nottingham NG7 2RD.

Liquid Extraction Surface Analysis (LESA) is a new, high throughput tool for ambient mass spectrometry. A solvent droplet is deposited from a pipette tip onto a surface and maintains contact with both the surface and the pipette tip for a few seconds before being re-aspirated. The technique is particularly suited to the analysis of trace materials on surfaces due to its high sensitivity and low volume of sample removal. Read More

Anal Methods 2016 Apr 1;8(15):3109-3114. Epub 2016 Apr 1.

Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, USA.

Lifetime-based oxygen imaging is useful in many biological applications but instrumentation can be stationary, expensive, and complex. Herein, we present a portable, cost effective, simple alternative with high spatiotemporal resolution that uses a complementary metal oxide silicon (CMOS) camera to measure oxygen sensitive lifetimes on the millisecond scale. We demonstrate its compatibility with difluoroboron β-diketonate poly(lactic acid) (BFbdkPLA) polymers which are nontoxic and exhibit long-lived oxygen sensitive phosphorescence. Read More

Anal Methods 2016 Jul 1;8(25):5152-5157. Epub 2016 Jun 1.

Department of Chemistry, Saint Louis University, St Louis, MO, 63130 USA.

Interfacing of microfluidic devices to mass spectrometry has challenges including dilution from sheath liquid junctions, fragile electrodes, and excessive dead volumes which prevent optimum performance and common use. The goal of this work is to develop a stable nanospray chip-MS interface that contains easily integrated electrodes and an embedded capillary emitter to mitigate current chip-MS problems. This system uses a hybrid polystyrene-poly(dimethylsiloxane) (PS-PDMS) microfluidic platform with an embedded electrode and integrated capillary emitter used as the nanospray interface. Read More

Anal Methods 2016 Nov 23;8(42):7661-7672. Epub 2016 Sep 23.

University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, VIRIS Laboratory, Konrad-Lorenz-Straße 24, 3430 Tulln, Austria.

The performance and validation characteristics of different single collector inductively coupled plasma mass spectrometers based on different technical principles (ICP-SFMS, ICP-QMS in reaction and collision modes, and ICP-MS/MS) were evaluated in comparison to the performance of MC ICP-MS for fast and reliable S isotope ratio measurements. The validation included the determination of LOD, BEC, measurement repeatability, within-lab reproducibility and deviation from certified values as well as a study on instrumental isotopic fractionation (IIF) and the calculation of the combined standard measurement uncertainty. Different approaches of correction for IIF applying external intra-elemental IIF correction (aka standard-sample bracketing) using certified S reference materials and internal inter-elemental IIF (aka internal standardization) correction using Si isotope ratios in MC ICP-MS are explained and compared. Read More

Anal Methods 2016 May 29;8(17):3550-3563. Epub 2016 Mar 29.

Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410008, China ; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha 410078, China.

The compound medicine of betamethasone sodium phosphate (BSP) and betamethasone dipropionate (BDP) is widely used for diverse glucocorticoid-sensitive acute and chronic diseases such as asthma, rheumatoid arthritis and systemic lupus erythematosus. It will be useful and beneficial to validate sensitive method for the determination of BSP, BDP and their metabolites for their pharmacokinetic study. Hereby, an ultra-high pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been validated for the determination of BSP, BDP and their metabolites betamethasone (BOH), betamethasone 17-monodipropionate (B17P) and betamethasone 21-monodipropionate (B21P) in human plasma. Read More

Anal Methods 2016 Apr 5;16(8):3325-3332. Epub 2016 Apr 5.

Department of Chemistry, Ralph N. Adams Institute for Bioanalytical Chemistry, Lawrence, KS 66047 ; University of Kansas, Lawrence, KS 66047.

A laboratory-built sheath liquid capillary electrophoresis-mass spectrometry interface was used to develop a qualitative method for fingerprinting analysis of 14 structurally similar flavones, flavonols, flavonones, and several representative glycosides in plant samples. The migration order of the flavonoids was dependent on a the number of hydroxyl groups present on the flavonoid B-ring, extent of conjugation, number of glycosidic functionalities, and ability of the flavonoid to form stable borate complexes with the background electrolyte. Parent ion scans of the flavonoids yielded [M-H], except for catechol containing flavonoids, which were detected as borate adducts. Read More

Anal Methods 2016 Aug 27;8(31):6005-6012. Epub 2016 Jul 27.

Department of Chemistry, Saint Louis University, Saint Louis, MO, USA.

A mini-review with 79 references. In this review, the most recent trends in 3D-printed microfluidic devices are discussed. In addition, a focus is given to the fabrication aspects of these devices, with the supplemental information containing detailed instructions for designing a variety of structures including: a microfluidic channel, threads to accommodate commercial fluidic fittings, a flow splitter; a well plate, a mold for PDMS channel casting; and how to combine multiple designs into a single device. Read More

Anal Methods 2016 Jul 23;8(28):5611-5618. Epub 2016 Jun 23.

National Institute of Standards and Technology, Materials Measurement Science Division, Gaithersburg, MD, USA.

The rapid and sensitive detection of sugar alcohol sweeteners was demonstrated using ion mobility spectrometry (IMS). IMS provides a valuable alternative in sensitivity, cost, and analysis speed between the lengthy gold-standard liquid chromatography-mass spectrometry (LC-MS) technique and rapid point-of-measurement disposable colorimetric sensors, for the Food and Nutrition industry's quality control and other "foodomics" area needs. The IMS response, characteristic signatures, and limits of detection for erythritol, pentaerythritol, xylitol, inositol, sorbitol, mannitol, and maltitol were evaluated using precise inkjet printed samples. Read More