Volume 39, Issue 1

Polycyclic aromatic hydrocarbons (PAHs) are a large group of organic compounds comprised of two or more fused benzene rings, which arise from the incomplete combustion of organic materials. These compounds have been of concern as carcinogens and mutagens for the past 50-60 years. Lately, they are also receiving attention as endocrine-disrupting chemicals. Therefore, proper analytical methods are required for sampling and analyzing these compounds. In response to problems associated with the conventional methods like solid-phase extraction (SPE) and liquid-liquid extraction (LLE), many studies have focused on the miniaturization of different sample preparation techniques. In this regard, the use of different types of liquid phase microextraction (LPME) techniques has increased significantly during the recent few decades. LPME techniques are advantageous because they use single-step sample preparation and have shown a greater sensitivity, selectivity, and efficiency than the conventional methods. In addition, these techniques have good potential for automation, to reduce the time and cost of analysis. This review focuses on the most important configurations of LPME including single‐drop microextraction (SDME), hollow-fiber liquid-phase microextraction (HF-LPME), and dispersive liquid-liquid microextraction (DLLME) techniques used for the sampling and determination of PAHs in different samples, along with their cons and pros, as well as their prospects.

Sensors, biosensors, lateral flow immunoassays, portable thin-layer chromatography and similar devices for hand-held assay are tools suitable for field or out of laboratories assays of various analytes. The assays frequently exert a limit of detection and sensitivity close to more expensive and elaborative analytical methods. In recent years, huge progress has been made in the field of optical instruments where digital cameras or light sensitive chips serve for the measurement of color density. General availability of cameras, a decrease of prices and their integration into wide spectrum phones, tablets and computers give the promise of easy application of analytical methods where such cameras will be employed. This review summarizes research on hand-held assays where small cameras like the ones integrated into smartphones are used. Discussion about such assays, their practical applicability and relevant specifications are also written here.

Ellagic acid is an important phytochemical present in different plants such as Strawberry, Grapes, Blackberry, Raspberry etc. Chemically, ellagic acid is 2, 3, 7, 8-tetrahydroxychromeno [5, 4, 3-cde] chromene-5, 10-dione. It is an organic heterotetracyclic compound resulting from the dimerization of gallic acid molecules by oxidative aromatic coupling with intramolecular lactonization. Ellagic acid has been reported for various pharmacological activities such as anti-inflammatory, neuroprotective, cardioprotective, antioxidant, anti-mutagenic etc. Various analytical methods based on spectrophotometry, chromatography, hyphenated techniques, capillary zone electrophoresis etc. have been developed for identification and quantification of ellagic acid in natural sources and formulations. The present review provides detailed information on quantitative analysis of ellagic acid present in Strawberry, Grapes, Blackberry, Raspberry, Cranberry; Syzygium cumini seed extract, Woodfordia fruticosa plant extract, Potentilla species extracts etc. It also focuses on analytical methods for quantification of ellagic acid in herbal and traditional formulations such as Ashwagandharishta, Triphala churna, Dhatrinisha churna, Arjunarishta, Manjisthadi churna.

Capillary electrophoresis (CE) coupled with mass spectrometry (MS) through electrospray ionization (ESI) is a promising alternative technique to liquid chromatography-ESI-MS (LC-ESI-MS) due to its high separation efficiency and high detection sensitivity. A sensitive and robust interface is essential in CE-ESI-MS. Continued development of CE-ESI-MS interfaces in the last decade, including junction-at-the-tip interfaces and sheathless interfaces, has improved the sensitivity and robustness of CE-ESI-MS significantly. The limited loading capacity of CE, one of major reasons that limits the utility of CE as a routine separation method, has also been addressed effectively by the use of in-capillary sample preconcentration techniques, such as transient CITP/CZE and dynamic pH junction. CE-ESI-MS could yield higher sensitivity as compared with the conventional LC-ESI-MS, and, therefore, is capable of identifying more proteins and peptides when the sample amount is very limited, such as single cell analysis. To improve the protein sequence coverage, CE-ESI-MS can also be used as a complementary technique to LC-ESI-MS, or combined with reversed phase LC to form a two dimensional separation technique. CE-ESI-MS is also effective in quantifying targeted peptides/proteins in complex bio-matrix.

A simple, rapid, sensitive, cheap and accurate oxidative method for two beta-blockers in pharmaceutical dosage forms was developed and evaluated. The method involved the oxidimetric treatment of atenolol and propanolol with 2 x 10-3 mol L-1 KMnO4 in alkaline medium (pH ≥ 9). Scanned spectra of oxidized complex showed distinctive absorptions at 460, 520, 540 and 570 nm. Arrays of colour changes were observed - from violet to blue; blue to bluish-green and yellow. Exhibited colours were due to ligand-metal charge transfer. An indirect spectrophotometric determination of atenolol and propranolol was done after 12-15 minutes at 520 nm. The optimum assay conditions showed linearity ranged from 0 – 15.0 μg mL-1 for both beta-blockers (R= 0.9997 – 0.9999). Molar absorptivity values were 4.79 x 103 and 4.88 x 103 L mol-1 cm-1 for atenolol and propanolol respectively, with corresponding Sandell’s sensitivity values of 0.056 and 0.053 μg cm-2. Limits of detection and quantification were 0.50 and 1.65 μg mL-1 for atenolol respectively and 0.58 and 1.91 μg mL-1 for propanolol, while relative standard deviation for intra-and inter-day precision were < 2.0%. The applicability, accuracy and reliability of the method were demonstrated by the determination of atenolol and propanolol in tablet formulations. The recovery studies ranged from 93.33 - 103.00% for both beta-blockers and the amounts in brands were from 97.53 ± 2.68 to 100.84 ± 1.82%.

Attention deficit hyperactivity disorder (ADHD) is a common neuro-developmental disorder. The symptoms of ADHD include difficulty in attention, memory and impulse control. Many pharmaceutical formulations (stimulants and non-stimulants) are available on the market to treat ADHD symptoms. The most commonly used drugs for treatment are amphetamine, methylphenidate, atomoxetine, bupropion, guanfacine and clonidine. In the field of pharmaceuticals, bioanalysis is an important tool used for the quantification of drugs and their metabolites present in biological samples using various analytical methods. Although a number of analytical methods were reported for the quantification of these drugs in biological samples of experimental animals, due to species differences, it is important to develop analytical methods to quantify these drugs in human biological samples to aid forensic and pharmacokinetic studies. In this review, we compile the bio-analytical methods such as spectrophotometry, spectrofluorimetry, mass spectrometry, electrophoresis, liquid chromatography and gas chromatography used for the quantification of ADHD drugs in human biological samples such as blood, plasma, serum, oral fluids, sweat, hair and urine based on earlier published articles from various journals.

Benzene, toluene, ethylbenzene, and xylene (BTEX) are a group of volatile organic compounds that human exposure to them may result in the development of some diseases, including cancer. Biological monitoring plays an important role in exposure assessment of workers occupationally exposed to chemicals. Several metabolites have been proposed for biological monitoring of individuals who are exposed to BTEX. There are a variety of extraction methods and analytical techniques for the determination of unmetabolized BTEX in exhaled air and their urinary metabolites. The present study aimed to summarize and review the toxicokinetics of BTEX and sample preparation and analytical methods for their measurement. Metabolites of BTEX are discussed to find out reliable ones for biological monitoring of workers exposed to these chemicals. In addition, analytical methods for unmetabolized BTEX in exhaled air and their metabolites were reviewed in order to obtain a comparison between them in term of selectivity, sensitivity, simplicity, time, environmental-friendly and cost. Given the recent trends in sample preparation, including miniaturization, automation, high-throughput performance, and on-line coupling with analytical instrument, it seems that microextraction techniques, especially microextraction by packed sorbents are the methods of choice for the determination of the BTEX metabolites.

Neurochemical recording techniques have expanded our understanding of the pathophysiology of neurological disorders, as well as the mechanisms of action of treatment modalities like deep brain stimulation (DBS). DBS is used to treat diseases such as Parkinson’s disease, Tourette syndrome, and obsessive-compulsive disorder, among others. Although DBS is effective at alleviating symptoms related to these diseases and improving the quality of life of these patients, the mechanism of action of DBS is currently not fully understood. A leading hypothesis is that DBS modulates the electrical field potential by modifying neuronal firing frequencies to non-pathological rates thus providing therapeutic relief. To address this gap in knowledge, recent advances in electrochemical sensing techniques have given insight into the importance of neurotransmitters, such as dopamine, serotonin, glutamate, and adenosine, in disease pathophysiology. These studies have also highlighted their potential use in tandem with electrophysiology to serve as biomarkers in disease diagnosis and progression monitoring, as well as characterize response to treatment. Here, we provide an overview of disease-relevant neurotransmitters and their roles and implications as biomarkers, as well as innovations to the biosensors used to record these biomarkers. Furthermore, we discuss currently available neurochemical and electrophysiological recording devices, and discuss their viability to be implemented into the development of a closed-loop DBS system.

Gas chromatography (GC) is an important and widely used technique for separation and analysis in the field of analytical chemistry. Micro gas chromatography has been developed in response to the requirement for on-line analysis and on-site analysis. At the core of micro gas chromatography, microelectromechanical systems (MEMs) have the advantages of small size and low power consumption. This article introduces the stationary phases of micro columns in recent years, including polymer, carbon materials, silica, gold nanoparticles, inorganic adsorbents and ionic liquids. Preparation techniques ranging from classical coating to unusual sputtering of stationary phases are reviewed. The advantages and disadvantages of different preparation methods are analyzed. The paper introduces the separation characteristics and application progress of MEMs columns and discusses possible developments.

In this work, a resonance Rayleigh scattering technique and a spectrofluorimetric technique were applied to the quantification of cyclobenzaprine through two validated methods. The suggested methods are based on a facile association complex formation between cyclobenzaprine and eosin Y reagent in the acidic medium. The resonance Rayleigh scattering method relied on the enhancement in the resonance Rayleigh scattering spectrum of eosin Y at 370 nm after the addition of cyclobenzaprine. On the other hand, the spectrofluorimetric quantification relied on the quenching effect of cyclobenzaprine on the fluorescence strength of the eosin Y reagent at 545 nm (excitation wavelength at 300 nm). The suggested methods were linear over the ranges of 0.07–1.75 μg/mL and 0.15–2.0 μg/mL with detection limit values of 0.023 μg/mL and 0.048 μg/mL for the resonance Rayleigh scattering method and the spectrofluorimetric method, respectively. All reaction conditions for cyclobenzaprine–eosin Y formation were experimentally evaluated and optimized. In addition, both methods were validated based on ICH rules. Furthermore, the developed methods were practically applied to the analysis of cyclobenzaprine in its commercial tablet dosage form with acceptable recoveries. Moreover, the content uniformity test of the commercial cyclobenzaprine tablets was successfully applied using the proposed spectroscopic methods based on USP rules.

Fast pyrolysis of lignocellulosic biomass is one of the most promising methods of the production of renewable fuels. However, an optimization of the conditions of bio-oil production is not possible without comprehensive analysis of the composition of formed products. There are several methods for the determination of distribution of products formed during thermal decomposition of biomass with chromatography being the most versatile among them. Although, due to the complex structure of bio-oil (presence of hundreds chemical compounds with different chemical character), an interpretation of the obtained chromatograms is not an easy task. Therefore, the aim of this work is to present an application of different chromatographic methods to the analysis of the composition of the mixture of products formed in high temperature decomposition of lignocellulosic feedstock. It includes pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), two dimensional gas (GC x GC) or liquid chromatography (LC x LC) and initial fractionation of bio-oil components. Moreover, the problems connected with the analysis of bio-oils formed with the use of various fast pyrolysis reactors and capabilities of multivariate analysis are discussed.

In this study, the levels of concentration of carboxylic acids (benzoic acid, p -hydroxybenzoic acid, p -hydroxyphenylacetic acid, and hippuric acid) in the urine of autistic children were investigated and compared. The increased excretion of carboxylic acids is related to excessive bacterial activity in the gut, called bacterial overgrowth, which has been related to autism spectrum disorder (ASD) as an impairment in the gut-brain axis. The investigation was based on the analysis of urine samples obtained from 120 ASD children. To identify and quantify urinary carboxylic acids (UCAs), we applied gas chromatography coupled with mass spectrometry (GC-MS). Additionally, we checked the influence of probiotic supplementation, gender, body mass index (BMI) value and age of children on the level of different selected compounds. Most of the obtained results were found within reference ranges. In some cases, the levels of benzoic acid, p -hydroxybenzoic acid, and p -hydroxyphenylacetic acid were particularly elevated. Statistically significant differences were observed in supplementation with probiotics and the level of p -hydroxyphenylacetic acid (p=0.036). The obtained results may indicate disturbances in the intestinal flora in some autistic patients and suggest that supplements may have an influence on the levels of carboxylic acids in urine. Due to the small population of children taking the supplement, further study are needed.

Lignocellulosic biomass is considered an attractive and most abundant renewable carbon feedstock. Hydroxymethylfurfural (HMF) is one of the platform molecules obtained from biomass. HMF transformation in the reductive atmosphere allows to obtain numerous value-added molecules with applications in several recently emerged sectors, e.g. biofuels and biopolymers. This process is still intensively investigated, and more efficient, stable and sustainable solutions are envisaged. Therefore, the choice of efficient analytical methods is of great importance. This review covers the methodologies used for the analysis of HMF hydrodeoxygenation, including chromatographic and spectrometric methods. Techniques such as gas chromatography, high-performance liquid chromatography, Fourier transform infrared spectroscopy, nuclear magnetic resonance, and mass spectrometry are mentioned as well in this review.

Given the strong associations between diet and cancer risk, there is considerable scientific interest in determining whether dietary factors associated with prostate cancer cell implantation may influence epigenetic alternations. The aim of the research was to assess impact of selected trace elements (selenium, zinc and copper) on the kinetics of changes (10-13-14-21 week of life cycle of rats) in the level of 7-methylguanine, 3-methyladenine, 1-methylguanine and 8-oxo-guanine in the urine of rats with implanted prostate cancer cells (LNCaP). Modified nucleobases were determined by validated high performance liquid chromatography coupled to mass spectrometry (LC-MS/MS) method using multiple reaction monitoring (MRM) mode. In the presented model the implantation of rats with cancer cells did not affect the level of the examined biomarkers in the rats’ urine. The level of methyl derivatives was statistically significantly reduced with the age of the examined rats. The implantation of rats with cancer cells results in the appearance of tumors in 71% of the rats obtaining the standard diet and respectively in 25% of those supplemented with selenium. Supplementation with selenium affects both the effectiveness of tumor induction and the concentration of 7-MeG, 3-MeA, 1-MeG and 8-oxoG in urine of the examined rats. These findings show that modified nucleosides can play an important role in cancer prevention.

Zearalenone (ZEN) is a mycotoxin that occurs in all stages of plant growth and development and exerts harmful effects on humans and animals. Zearalenone is easily absorbed in the digestive tract, and it is metabolized in the intestinal wall and the liver. Zearalenone has several derivatives: zearalenone, zearalanone (ZAN), α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), α-zearalanol (α-ZAL) and β-zearalanol (β-ZAL). These substances have a high affinity for estrogen receptors, and they can gradually affect the endocrine system. Excess ZEN and its metabolites are excreted with urine and bile. This paper analyzes ZEN metabolism and investigates the presence of ZEN and its metabolites in urine. Since the isolation of ZEN and its metabolites from different matrices still poses a significant problem, the paper also presents various sample preparation methods (including liquid-solid extraction, liquid-liquid extraction and other techniques) as well as sensitive and specific chromatographic techniques, including liquid chromatography (LC) with fluorescence and mass spectrometry detection, gas chromatography (GC) and thin-layer chromatography (TLC).

The aim of the research was to compare the impact of nano- and micro-sized-zinc on the kinetics of changes in the level of 3-methyladenine, 7-methylguanine, 7-methylguanosine, O-methylguanosine, 1-methyladenosine, N6-methyl-2’-deoxyguanosine in urine of rats with breast cancer. Female Sprague-Dawley rats divided into 3 groups were used in the study. Animals were fed only a control diet or diets supplemented with the nano and micro-sized zinc particles. To induce the mammary cancer ( adenocarcinoma ), rats were treated with 7,12-dimethylbenz[a]anthracene (DMBA). Modified nucleosides were determined by a validated high performance liquid chromatography coupled to mass spectrometry method. In the first stage of investigations a synergistic activity of nanosized Zn with DMBA on the growth of the neoplastic process was found. During that time a statistically significant increase in the levels of all six examined markers in the rats’ urine was observed. However, as the experiment continued, the supplementation with nanosized zinc caused inhibition of tumour growth, being followed by regression and remission of tumours, as well as, a statistically significant systematic reduction of the levels of methyl derivatives in the urine. Biopsy images indicated grade 1 tumours with multiple inflammatory infiltrates in the group treated with zinc nanoparticles, whereas, in the other groups, moderately-differentiated grade 2 adenocarcinoma was identified. It was found that the biological activity of zinc depends on the size of applied particles, as the treatment with zinc microparticles has not had much effect on cancer progression.

The quantification of the interactions between biomolecules and materials interfaces is crucial for design and synthesis functional hybrid bionanomaterials for materials science, nanotechnology, biosensor, biomedicine, tissue engineering, and other applications. Atomic force spectroscopy (AFM)-based single-molecule force spectroscopy (SMFS) provides a direct way for measuring the binding and unbinding forces between various biomolecules (such as DNA, protein, peptide, antibody, antigen, and others) and different materials interfaces. Therefore, in this review, we summarize the advance of SMFS technique for studying the interactions between biomolecules and materials interfaces. To achieve this aim, firstly we introduce the methods for the functionalization of AFM tip and the preparation of functional materials interfaces, as well as typical operation modes of SMFS including dynamic force spectroscopy, force mapping, and force clamping. Then, typical cases of SMFS for studying the interactions of various biomolecules with materials interfaces are presented in detail. In addition, potential applications of the SMFS-based determination of the biomolecule-materials interactions for biosensors, DNA based mis-match, and calculation of binding free energies are also demonstrated and discussed. We believe this work will provide preliminary but important information for readers to understand the principles of SMFS experiments, and at the same time, inspire the utilization of SMFS technique for studying the intermolecular, intramolecular, and molecule-material interactions, which will be valuable to promote the reasonable design of biomolecule-based hybrid nanomaterials.

In recent years, nanomaterials have attracted lots of attention from researchers due to their unique properties. Nanometer fluorescent materials, such as organic dyes, semiconductor quantum dots (QDs), metal nano-clusters (MNCs), carbon dots (CDs), etc., are widely used in biological imaging due to their high sensitivity, short response time, and excellent accuracy. Nanometer fluorescent probes can not only perform in vitro imaging of organisms but also achieve in vivo imaging. This provides medical staff with great convenience in cancer treatment. Combined with contemporary medical methods, faster and more effective treatment of cancer is achievable. This article explains the response mechanism of three-nanometer fluorescent probes: the principle of induced electron transfer (PET), the principle of fluorescence resonance energy transfer (FRET), and the principle of intramolecular charge transfer (ICT), showing the semiconductor QDs, precious MNCs, and CDs. The excellent performance of the three kinds of nano fluorescent materials in biological imaging is highlighted, and the application of these three kinds of nano fluorescent probes in targeted biological imaging is also introduced. Nanometer fluorescent materials will show their significance in the field of biomedicine.

Metal ions are widely present in biological systems and participate in many critical biochemical processes such as material transportation, energy conversion, information transmission and metabolic regulation, making them indispensable substance in our body. They can cause health problems when deficiency or excess occurs. To understand various metabolic processes and facilitate diseases diagnosis, it is very important to measure the content and monitor the distribution of metal ions in individual cells, tissues and whole organisms. Among the various methods for metal ion detection, fluorescent sensors with organic dyes have attracted tremendous attention due to many advantages such as high fluorescence quantum yield, facile modification approaches and biocompatibility in addition to operation ease, high sensitivity, fast detection speed, and real-time detection. This review summarizes the recent progress on the detection and imaging of the metal ions in biological systems including Na + , K + , Ca 2+ , Mg 2+ , Fe 2+ /Fe 3+ , Zn 2+ , and Cu 2+ provides an opinion on remaining challenges to be addressed in this field.

Gelatin, a natural functional material obtained from animal connective tissues, has been broadly applied in health-related products such as food, pharmacy, and cosmetic. But unclear labelling and false information of animal origin of gelatin in those products would violate religious rules and increase public health risks. Recently, animal origin identification of gelatin-based products has drawn more and more concerns. Among various identification methods, liquid chromatography-mass spectrometry (LC-MS) has specifically become a research hotspot for animal origin identification and quantitative analysis of gelatin-based products due to its superior reliability, selectivity, and sensitivity. The main desideratum of the current treatise is to review the recent progress on this subject with respect to: (1) the identification of animal in halal gelatin-based products, (2) the determination of the authenticity of gelatinous medicines from animal, especially from the highly homologous family species, and (3) the quantification of gelatin in gelatin-based products, using LC-MS method. We hope that this review could provide theoretical guidance and advanced strategies for developing animal origin identification technologies for gelatin-based products.