Analytical Letters

Sharma, Sweta; Jaiswal, Aarti; Uttam, K. N.

doi: 10.1080/00032719.2020.1743715pmid: N/A

AbstractFor maintaining water quality, planning remediation strategies and ecosystem restoration, the detection of metal ions in aquatic water bodies is very important. Colorimetry as well as plasmon-enhanced spectroscopy using plasmonic particles tailored and decorated by organic molecules provides promising simple, portable, robust and economically viable sensing systems for metal ions in field or in point of care settings. For this purpose, silver nanoparticles functionalized with pectin (P-AgNPs) have been synthesized by a microwave assisted method for the detection of metal ions [Cr(III), Cr(VI), Se(IV), Mn(II), Fe(II), As(V), and Hg(I)] in aqueous solution using colorimetry and SERS. The addition of P-AgNPs imparts a black and brown color to the water samples containing Fe(II) and Mn(II) ions while a reddish brown color is observed in water samples containing Cr(III) and As(V) ions. The Raman measurements of different concentrations of Cr(III), Cr(VI), Se(IV), Mn(II), As(V), and Hg(I) ions mixed with synthesized colloidal P-AgNPs solution have also been recorded. The addition of metal ions to the P-AgNPs solution induces alteration in the spectral features of the peaks of P-AgNPs. In addition, they also lead to formation of new characteristic bands. Significant enhancement in the intensity has been observed for these bands in the form of SERS signals. These peculiar characteristic peaks may be used for the detection of the metal ions in aqueous solution. This study demonstrates applicability of P-AgNPs as a colorimetric and plasmon enhancing spectroscopic agent for the simple, prompt, easily accessible and portable tool for the detection of metal ion pollution in aqueous medium.

Benlaribi, Rabia; Schramm, Sébastien; Vincent, Bryan; Djebbar, Safia; Aubriet, Frédéric

doi: 10.1080/00032719.2020.1743997pmid: N/A

AbstractThe concentrations of twelve dioxin-like polychlorobiphenyls (DL-PCB) were determined in fifty-seven soils by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). The investigated soils were collected in a 72 km2 area close to Algiers, the Algerian capital. The highest cumulated DL-PCB concentration was close to 82 µg kg−1. The use of principal component analysis (PCA) ensured the tentative identification of the contamination sources, which were found to be associated with the release into the environment of PCB commercial mixtures from electrical transformers or from open burning of household wastes. The associated toxic equivalent quantity (TEQ) relative to the 12 DL-PCBs did not exceeded 2.8 ng.kg−1. The use of the United States Environmental Protection Agency guidelines ensured to define that neither the cancer potential human health risk nor the non-carcinogenic risk were significantly increased by the DL-PCB concentrations in the investigated soils.

Na, Situ; Hai, Reti; Wang, Xiaohui; Li, Nankun; Chen, Daying

doi: 10.1080/00032719.2020.1744161pmid: N/A

AbstractAn analytical method based on liquid chromatography with triple quadrupole mass spectrometry has been developed to monitor 16 perfluorinated compounds in sludge samples. The sludge samples were collected from three wastewater treatment plants that were located in a perfluorinated compound production region (Yingcheng City), electroplating industrial region (Cixi City), and a background area (Haikou City). The average annual concentrations of total perfluorinated compounds in sludge samples were from 4.95 to 980 ng·g−1 dry weight. Perfluoro-octane sulfonic acid and perfluoro-octanoic acid were the predominant chemicals in these three wastewater treatment plants. The levels of total perfluorinated compounds were higher in summer than in winter. This phenomenon may be due to input from rainfall in the summer, which may contain more perfluorinated compounds from the surface soil or atmosphere in those regions. Similar sources were found in Yingcheng City and Cixi City based on principal component analysis.

Islam, Md Atikul; Ryu, Keun Young; Khan, Naeem; Song, Ok Yeon; Jeong, Ji Young; Son, Ji Hyeon; Jamila, Nargis; Kim, Kyong Su

doi: 10.1080/00032719.2020.1744160pmid: N/A

AbstractFive varieties of Piper betle L. var. leaves including Bangla, Sanchi, Misti, Khasia, and BARI Paan 3 from Bangladesh were subjected to the analysis of their volatile compounds. Simultaneous distillation extraction (SDE) with 1:1 (v/v) n-pentane:diethylether was used for the isolation of the volatile compounds while the analysis was done by gas chromatography/mass spectrometry (GC/MS). From the results, the Misti betel leaf variety showed the highest concentration of volatile compounds (13959 mg/kg) followed by BARI Paan 3 (11684 mg/kg), Khasia (11110 mg/kg), Sanchi (6959 mg/kg) and Bangla (4347 mg/kg). A total of 101 compounds were identified in which 42 were present in all of the varieties but at varying concentrations. The present study reports 50 volatile compounds in betel leaves for the first time in the literature. Eugenol was found in all of the varieties at the highest concentration value followed by β-caryphyllene, γ-muurolene, valencene, eucalyptol, chavicol and caryphellene oxide. Based on the volatile compounds, the five varieties of betel leaf were differentiated into three clusters by the use of principal component analysis (PCA). Hierarchical cluster analysis (HCA) also divided the leaf varieties into three clusters composed of Misti and BARI Paan 3, Bangla and Sanchi, and Khasia.

Turan, Nouha Bakaraki; Erkan, Hanife Sari; Chormey, Dotse Selali; Cağlak, Abdulkadir; Bakirdere, Sezgin; Engin, Guleda Onkal

doi: 10.1080/00032719.2020.1745222pmid: N/A

AbstractQuorum quenching using different kinds of inhibitors is a new subject of research that is used for biofilm prevention in wastewater treatment membrane systems. In this study, three natural compounds, namely tea, coffee and vanillin, were tested in order to evaluate their possible effects on wastewater sludge characteristics in a batch type aerobic reactor. The parameters evaluated included the soluble microbial products (total soluble microbial products, protein and carbohydrate fraction of soluble microbial products), extracellular polymeric substance concentrations (total extrapolymeric substances, protein and carbohydrate fraction of the extrapolymeric substances), floc size, zeta potential, sludge volume index and capillary suction time. The effects of these plant based compounds upon the quorum sensing N-butyryl-L-homoserine lactone signal were also investigated using gas chromatography – mass spectrometry (GC-MS) under optimized conditions. The results indicated different effects for each natural compound upon the sludge characteristics. The role of these natural compounds as quorum quenchers in the batch-type aerobic reactor was inconclusive due to their effects on extraction outputs. Understanding the effect of quorum quenchers on sludge characteristics is important and recent studies have been aimed at preventing biofilm formation in membrane bioreactors.

Ross, Natasha; Civilized Nqakala, Noniko

doi: 10.1080/00032719.2020.1745223pmid: N/A

AbstractThe synergism of phosphomolybdic acid hydrate (POM) decorated with silver-iron (III) oxide (Ag-Fe2O3) nanoparticles and anchored on reduced graphene oxide (RGO) have been demonstrated to be effective as a nonenzymatic H2O2 sensor platform. The assembly of the sensor components and their interactions were probed morphologically, spectroscopically and electrochemically. The Ag-Fe2O3/POM/RGO nanocomposite sensor provided an enhanced electroactive surface area, electrical conductivity and sensitivity for hydrogen peroxide compared to an unmodified glassy carbon electrode (GCE) at –0.55 V versus a saturated calomel electrode. The developed sensor amperometric response was linear across the concentration range from 0.3 mM to 3.3 mM (R2 = 0.992) with a detection limit and sensitivity of 0.2 μM and 271 μA·mM‒1·cm−2 respectively. Concomitantly, a short response time of T90 < 5 sec at a signal-to-noise ratio of 4 was achieved. The sensor was shown to determine hydrogen in the presence of interfering species, and exhibited high selectivity with relative standard deviation values less than 4.2%. The results indicate that the use of RGO to anchor and photochemically reduce POM also improved the reduction properties due to the irregular size distribution and catalytic activity of Ag-Fe2O3 stimulated by its adhesion to the distinctive POM/RGO matrix.

Whitford, Evan; Nzobigeza, Winnifrida; Kradtap Hartwell, Supaporn

doi: 10.1080/00032719.2020.1745224pmid: N/A

AbstractA green analytical paper based assay of Cu (II) has been developed using egg white protein as a natural reagent. Either crayon and pencil graphite, or laser engraver may be used to effectively create hydrophobic barriers and hydrophilic reaction zones on the filter paper substrate. The reaction is observed via the Biuret test’s principle of Cu (II) ions reacting with nitrogen in the peptide bonds of the egg white under alkaline conditions to form a purple complex. Graphics editing software was used to determine the RGB values or grayscales of the reaction for the construction of a calibration graph. The volumes of reagents and samples were as low as 3 to 5 µL each. The limits of detection and limit of quantitation were determined to be 0.0002 M (0.04 µg Cu) and 0.0007 M (0.13 µg Cu), respectively. The main benefits of the proposed paper based assay compared to the use of a spectrophotometer are its ability to work with turbid reagents and samples and its portability. In addition, the color of egg white-Cu (II) complex is stable for a long period (at least two weeks) which allows flexible time for data analysis. This method has been shown to tolerate the presence of other ions, i.e., Al (III), Ca (II), Mg (II), and Zn (II) at concentrations at least 50 times of those of the analyte, and can tolerate the presence of Fe (II) up to the same concentration of Cu (II). The proposed paper based assay was demonstrated to successfully determine various Cu (II) salts in supplement samples.

Shuang, Yazhou; Cao, Zhigang; Zhang, Tianci; Li, Laisheng

doi: 10.1080/00032719.2020.1745821pmid: N/A

AbstractA mono-6-(4-nitrophenyl)-ureido-β-cyclodextrin-bonded chiral stationary phase (NCDSP), containing π-electron withdrawing groups, was prepared by immobilizing a self-prepared mono-6-(4-nitrophenyl)-ureido-β-cyclodextrin ligand onto ordered mesoporous silica gel SBA-15, on which the ligand was synthesized by the reaction of mono-6-amino-β-cyclodextrin with 4-nitrophenylisocyanate. The structure of NCDSP was characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis and solid nuclear magnetic resonance. The introduction of electron-withdrawing (π-acidic) groups facilitated the separation of the π-electron-rich (π-basic) triazole chiral pesticides. In addition, the ureido group linkage allowed NCDSP to be a hydrogen bond-accepting and -donating chiral station phase and prevented the hydrolysis associated with nitrobenzoate and nitrophenylcarbamate linkages. As a result, the enantioseparations of nine triazole pesticides were achieved using NCDSP. Meanwhile, the chromatographic conditions, such as the pH and the composition of mobile phases, were investigated in detail. Moreover, in a comparative study with a cyclodextrin stationary phase (CDSP), the NCDSP provided higher enantioselectivity. Baseline separations for most of these triazoles on NDCSP were observed in relatively short times from 10 to 20 min. The highest resolution achieved was 2.87. Otherwise, incomplete enantiomeric separation was observed on the CDSP with a maximum resolution of less than 1.18. For the NCDSP, in addition to the inclusion effect, the π-π interaction between the electron-deficient stationary phase and the electron-donating triazoles significantly contributed to the chiral separation. This work reports a simple and convenient method for the preparation of the NCDSP with the rapid separation of chiral triazole pesticides.

Tian, Zhizhang; Xing, Lixia; Li, Dengke; Ma, Lichao; Wu, Ruoxin; Tian, Nan; Zhang, Chuntao

doi: 10.1080/00032719.2020.1746325pmid: N/A

AbstractA novel analytical method for the simultaneous determination of inorganic tin and organotin in tobacco was established for the first time. The extraction efficiencies of methanol, n-hexane, dichloromethane, ethyl acetate and the mobile phase were investigated. The mobile phase was selected to promote the extraction of tin from tobacco. Eight species of tin including inorganic tin (IT), trimethyltin (TMT), monophenyltin (MPhT), monobutyltin (MBT), diphenyltin (DPhT), dibutyltin (DBT), triphenyltin (TPhT) and tributyltin (TBT) were effectively separated and determined within 25 min using high-performance liquid chromatography – inductively coupled plasma – mass spectrometry (HPLC-ICP-MS). The detection limits were from 0.18 to 0.43 ng mL−1, and the recoveries were between 73.9% and 98.4%. The developed method was successfully employed to analyze tobacco samples. The results showed that inorganic tin was the major component of Sn in the tobacco samples with trace quantities of organotins also detected.

Zhou, Jingtao; Zheng, Yuhong; Zhang, Ji; Karimi-Maleh, Hassan; Xu, Yuting; Zhou, Qinwei; Fu, Li; Wu, Weihong

doi: 10.1080/00032719.2020.1746327pmid: N/A

AbstractElectrochemical profiles of Lycors radiata, L. aurea, L. sprengeri, L. longituba and L. chinensis were recorded from the embryo tissue of seeds. Differential pulse voltammetry (DPV) measurements recorded after water/ethanol extraction using phosphate buffer/acetic buffer may be used to develop patterns for species identification. The voltammetric measurements of the embryo tissue contain the electrochemical active compound profile belong to the species. As the distribution of chemical compounds in plants is controlled by genes, these profiles may reflect differences at the genetic level between the species. The dendrogram deduced from the electrochemical profile has been used as evidence for infrageneric relationship investigation.