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Analytica Chimica Acta (v.691, #1-2)

Editorial Board (pp. iii).

Development of a gas diffusion probe for the rapid measurement of pCO₂ in aquatic samples by Peter A. Faber; Perran L.M. Cook; Ian D. McKelvie; Peter S. Ellis (pp. 1-5).

A probe for the direct measurement of the partial pressure of carbon dioxide (pCO₂) in aqueous samples is described. It consists of a gas permeable membrane tube containing a flowing acceptor stream of bromothymol blue indicator solution. Carbon dioxide diffuses across the membrane causing a pH change in the acceptor. This pH change decreases the absorbance of the acid–base indicator which is detected photometrically, with high sensitivity using a multi-reflection photometric detector with an LED light source. Unlike many other common methods used to measure pCO₂, this probe has the advantage of not requiring sampling to perform measurements, and avoids potential losses and contamination. This probe has the potential to perform experiments requiring in situ measurements of pCO₂, allowing regular measurements of closed system experiments, without removing any of the water column. Compared to indirect methods used to measure pCO₂, this probe has the potential to provide more portable and faster measurements. The sensitivity, sampling rate and linear range of the probe can be tuned depending on the required sensitivity and range of measurements, and a measurement rate of at least 36h⁻¹ can be achieved. An application of this probe in real-time analysis of pCO₂ flux in a sediment core during a large deposition of organic matter has been described. As a comparison, the measurements of the probe have been plotted against pCO₂ calculated from alkalinity using a Gran titration. It is envisaged that the probe could be used for experiments in the laboratory requiring real time in situ measurements, or incorporated into a portable instrument so that field measurements can be easily performed. Although the linear range and sensitivity of this probe can be tuned, the configuration described gave a linear response over the calibration range of 0–5800μatm pCO₂, with a detection limit of 144μatm. The precision was 1.2% RSD ( n=13) at 430μatm.

Keywords: Key words; pCO; ₂; Real-time measurement; Sensor; Flow analysis

Recent applications of carbon-based nanomaterials in analytical chemistry: Critical review by Karen Scida; Patricia W. Stege; Gabrielle Haby; Germán A. Messina; Carlos D. García (pp. 6-17).

The objective of this review is to provide a broad overview of the advantages and limitations of carbon-based nanomaterials with respect to analytical chemistry. Aiming to illustrate the impact of nanomaterials on the development of novel analytical applications, developments reported in the 2005–2010 period have been included and divided into sample preparation, separation, and detection. Within each section, fullerenes, carbon nanotubes, graphene, and composite materials will be addressed specifically. Although only briefly discussed, included is a section highlighting nanomaterials with interesting catalytic properties that can be used in the design of future devices for analytical chemistry.

Keywords: Carbon-based nanomaterials; Separations; Detection; Sample preparation

Atomic spectrometry methods for wine analysis: A critical evaluation and discussion of recent applications by Guillermo Grindlay; Juan Mora; Luis Gras; Margaretha T.C. de Loos-Vollebregt (pp. 18-32).

The analysis of wine is of great importance since wine components strongly determine its stability, organoleptic or nutrition characteristics. In addition, wine analysis is also important to prevent fraud and to assess toxicological issues. Among the different analytical techniques described in the literature, atomic spectrometry has been traditionally employed for elemental wine analysis due to its simplicity and good analytical figures of merit. The scope of this review is to summarize the main advantages and drawbacks of various atomic spectrometry techniques for elemental wine analysis. Special attention is paid to interferences (i.e. matrix effects) affecting the analysis as well as the strategies available to mitigate them. Finally, latest studies about wine speciation are briefly discussed.

Keywords: Atomic spectrometry; Wine; Elemental analysis; Matrix effects

Application of new methodologies based on design of experiments, independent component analysis and design space for robust optimization in liquid chromatography by Benjamin Debrus; Pierre Lebrun; Attilio Ceccato; Gabriel Caliaro; Eric Rozet; Iolanda Nistor; Radu Oprean; Francisco J. Rupérez; Coral Barbas; Bruno Boulanger; Philippe Hubert (pp. 33-42).

HPLC separations of an unknown sample mixture and a pharmaceutical formulation have been optimized using a recently developed chemometric methodology proposed by W. Dewé et al. in 2004 and improved by P. Lebrun et al. in 2008. This methodology is based on experimental designs which are used to model retention times of compounds of interest. Then, the prediction accuracy and the optimal separation robustness, including the uncertainty study, were evaluated. Finally, the design space (ICH Q8(R1) guideline) was computed as the probability for a criterion to lie in a selected range of acceptance. Furthermore, the chromatograms were automatically read. Peak detection and peak matching were carried out with a previously developed methodology using independent component analysis published by B. Debrus et al. in 2009. The present successful applications strengthen the high potential of these methodologies for the automated development of chromatographic methods.

Keywords: High-performance liquid chromatography; Method development; Separation optimization; Experimental design; Design space; Independent component analysis

Hierarchical CuO nanochains: Synthesis and their electrocatalytic determination of nitrite by Cao Xia; Cai Xiaolan; Wang Ning; Guo Lin (pp. 43-47).

Microspheres with multilevel structure are widely used as removable catalysts, adsorbents, drug carriers and imaging contrast agents due to their hierarchical porosity. In this paper a facile wet chemical method for the synthesis of hierarchically nanostructured CuO chains assembled with small nanorods is reported. The as prepared nanomaterial is characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HRTEM). The autocatalytic response to nitrite ions is also carried out, which exhibits a wide linear range (0.004–3.7mM), sound sensitivity (177.9μAmg⁻¹dL⁻¹cm⁻²), highly reproducible response (R.S.D. of 2.0%), and an excellent long-term stability. The good analytical performance, low cost and straightforward preparation method make this novel electrode material promising for the development of effective nitrite sensors.

Keywords: CuO; Hierarchical nanostructure; Electrocatalysis; Nitrite

Microwave-assisted nonionic surfactant extraction of aliphatic hydrocarbons from petroleum source rock by A. Akinlua; M.A. Jochmann; J. Laaks; A. Ewert; T.C. Schmidt (pp. 48-55).

The extraction of aliphatic hydrocarbons from petroleum source rock using nonionic surfactants with the assistance of microwave was investigated and the conditions for maximum yield were determined. The results showed that the extraction temperatures and kinetic rates have significant effects on extraction yields of aliphatic hydrocarbons. The optimum temperature for microwave-assisted nonionic surfactant extraction of aliphatic hydrocarbons from petroleum source rock was 105°C. The optimum extraction time for the aliphatic hydrocarbons was at 50min. Concentration of the nonionic surfactant solution and irradiation power had significant effect on the yields of aliphatic hydrocarbons. The yields of the analytes were much higher using microwave assisted nonionic surfactant extraction than with Soxhlet extraction. The recoveries of the n-alkanes and acyclic isoprenoid hydrocarbons for GC–MS analysis from the extractant nonionic surfactant solution by in-tube extraction (ITEX 2) with a TENAX TA adsorbent were found to be efficient. The results show that microwave-assisted nonionic surfactant extraction (MANSE) is a good and efficient green analytical preparatory technique for geochemical evaluation of petroleum source rock.

Keywords: Nonionic surfactant; Hydrocarbons; Microwave extraction; In-tube extraction; Source rock

Fast screening of perfluorooctane sulfonate in water using vortex-assisted liquid–liquid microextraction coupled to liquid chromatography–mass spectrometry by Aikaterini Papadopoulou; Iván P. Román; Antonio Canals; Konstantina Tyrovola; Elefteria Psillakis (pp. 56-61).

Fast screening of trace amounts of the perfluorooctane sulfonate anion (PFOS) in water samples was performed following a simple, fast and efficient sample preparation procedure based on vortex-assisted liquid–liquid microextraction (VALLME) prior to liquid chromatography–mass spectrometry. VALLME initially uses vortex agitation, a mild emulsification procedure to disperse microvolumes of octanol, a low density extractant solvent, in the aqueous sample. Microextraction under equilibrium conditions is thus achieved within few minutes. Subsequently, centrifugation separates the two phases and restores the initial microdrop shape of the octanol acceptor phase, which can be collected and used for liquid chromatography–single quadrupole mass spectrometry analysis. Several experimental parameters were controlled and the optimum conditions found were: 50μL of octanol as the extractant phase; 20mL aqueous donor samples (pH=2); a 2min vortex extraction time with the vortex agitator set at a 2500rpm rotational speed; no ionic strength adjustment. Centrifugation for 2min at 3500rpm yielded separation of the two phases throughout this study. Enhanced extraction efficiencies were observed at low pH which was likely due to enhanced electrostatic interaction between the negatively PFOS molecules and the positively charged octanol/water interface. The effect of pH was reduced in the presence of sodium chloride, likely due to electrical double layer compression. The linear response range for PFOS was from 5 to 500ngL⁻¹ (coefficient of determination, r², 0.997) and the relative standard deviation for aqueous solutions containing 10 and 500ngL⁻¹ PFOS were 7.4% and 6.5%, respectively. The limit of detection was 1.6ngL⁻¹ with an enrichment factor of approximately 250. Analysis of spiked tap, river and well water samples revealed that matrix did not affect extraction.

Keywords: Sample preparation; Perfluorooctane sulfonate; Vortex-assisted liquid–liquid microextraction; Liquid chromatography–mass spectrometry; Water analysis; Solution chemistry

Systematic screening of protein modifications in four kinases using affinity enrichment and mass spectrometry analysis with unrestrictive sequence alignment by Kai Zhang; Yixin Zhu; Xiwen He; Yukui Zhang (pp. 62-67).

Protein kinases transfer phosphate groups from ATP to substrate proteins, they are known to be involved in diverse cellular processes. They are also important therapeutic targets in pharmaceutical design. Previous studies indicated that multiple post-translational modifications (PTMs) exist in kinases in addition to phosphorylation, and these PTMs play an important role in regulating kinases activities. Nevertheless, a comprehensive analysis for PTMs of kinases is insufficient due to technical limitations, which prevent us from better understanding their functional regulation. Here, we have developed a novel strategy that combines glutathione S-transferase tag affinity enrichment with nano-liquid chromatography coupled with tandem mass spectrometry analysis and non-restrictive protein sequence alignment for identification of diverse PTMs in four yeast kinases. The method allows us to enrich and analyze the entire protein isomers and to minimize the loss of all isomers of protein sample during protein purification. In our study, nineteen phosphorylation sites and several other types of PTMs sites were localized in 4 protein kinases. In addition, we found that some interesting mass shifts can not match those of the known PTMs. It suggested the existence of some undescribed PTMs in the proteins. Accordingly, this study showed that the novel strategy holds a great potential for identification of full-spectrum PTMs in proteins. Our data serves as a stepping stone for future functional studies.

Keywords: Mass spectrometry; Post-translational modifications; Phosphorylation; Glutathione S-transferase tag; Affinity enrichment; Kinase

Fecal metabolome profiling of liver cirrhosis and hepatocellular carcinoma patients by ultra performance liquid chromatography–mass spectrometry by Hongcui Cao; Haijun Huang; Wei Xu; Deying Chen; Jiong Yu; Jun Li; Lanjuan Li (pp. 68-75).

Fecal metabolome of healthy humans and patients suffering from liver cirrhosis and hepatocellular carcinoma (HCC) were studied using ultra performance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF MS). Metabolic features detected by the method were then statistically treated using partial least squares to latent structure-discriminant analysis (PLS-DA) models to discriminate between healthy and diseased states. PLS-DA was also used to discriminate between cirrhosis and HCC stressed fecal metabolomes and to identify potential biomarkers for cirrhosis and HCC that are expressed at significantly different amounts in fecal metabolomes.Score plots of pattern recognition analysis distinguished liver cirrhosis and HCC patients from healthy humans. Based on the variable of importance in the project (VIP) values and S-plots, six metabolites were considered as potential biomarkers with a strong increase in lysophosphatidylcholines and a dramatic decrease in bile acids and bile pigments in patients with liver cirrhosis and HCC in comparison with healthy humans. Results demonstrate the potential of UPLC-MS as an efficient and convenient method that can be applied to screen fecal samples and aid in the early diagnosis of cirrhosis and hepatocellular carcinoma.

Keywords: Abbreviations; UPLC/Q-TOF MS; ultra performance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry; HCC; hepatocellular carcinoma; PLS-DA; partial least squares to latent structure-discriminant analysis; VIP; variable of importance in the project; AFP; alfa-fetoprotein; CT; computed tomography; MRI; magnetic resonance imaging; LC-MS; liquid chromatography–mass spectrometry; ESI; electrospray ionization; OPLS; orthogonal partial least squares; BPI; base peak intensity; LPC; lysophosphatidyl choline; NMR; nuclear magnetic resonance; HPLC; high-performance liquid chromatographyMetabonomics; Fecal water extracts; Hepatocellular carcinoma; Liver cirrhosis

Kinetic–spectrometric three-dimensional chemiluminescence as an effective analytical tool. Application to the determination of benzo(a)pyrene by José Antonio Murillo Pulgarín; Luisa F. García Bermejo; M. Nieves Sánchez García; Ignacio Sánchez-Ferrer Robles (pp. 76-82).

Kinetic and spectroscopic methods were used in combination in this work to develop a new analytical tool for use in chemiluminescence detection processes. Specifically, time-resolved chemiluminescence was used jointly with a stopped-flow assembly in order to monitor the chemiluminescence produced in the oxidation of bis(2,4-dinitrophenyl)oxalate (DNPO) by hydrogen peroxide in the presence of a polycyclic aromatic hydrocarbon. Recording of successive two-dimensional spectra during the emission process and treating the acquired spectral data with dedicated software allows the obtainment of three-dimensional chemiluminescence spectra, a result of the joint use of two analytical techniques. Thus, using a flow cell specifically designed for direct coupling to the charge-coupled device (CCD) detector increases the emission intensity without the need for fibre optics. Also, using dedicated software to process the acquired two-dimensional spectra affords a comprehensive kinetic and spectroscopic characterization of the chemiluminescence signal via the three-dimensional spectrum previously obtained.The analytical potential of this new tool was assessed by application to the chemiluminescent reaction between a peroxyoxalate and an oxidant (hydrogen peroxide); the reaction is induced by benzo( a)pyrene, which was used to determine this polycyclic aromatic hydrocarbon in an organic solvent. A linear calibration graph was obtained between 0.5 and 20mgL⁻¹. The limit of detection found to be 3.97μgL⁻¹ and a relative standard error of 0.64% and a relative standard deviation of 1.87% were obtained. The results reached testify to the usefulness of the proposed analytical tool for simple determinations and its potential for the resolution of complex mixtures or determinations in complex matrices.

Keywords: Chemiluminescence; Three-dimensional; Kinetic; Spectroscopic; Benzo(a)pyrene; Peroxyoxalates

Development of a heterobimetallic Ru(II)–Cu(II) complex for highly selective and sensitive luminescence sensing of sulfide anions by Run Zhang; Xiaojing Yu; Yuejiao Yin; Zhiqiang Ye; Guilan Wang; Jingli Yuan (pp. 83-88).

A heterobimetallic ruthenium(II)–copper(II) complex-based luminescent chemosensor, [Ru(bpy)₂(bpy-DPA)Cu]⁴⁺ (bpy: 2,2′-bipyridine; bpy-DAP: 4-methyl-4′-[ N, N-bis(2-picolyl)amino-methylene]-2,2′-bipydine), has been designed and synthesized for the highly selective and sensitive recognition and detection of sulfide anions in 100% aqueous solutions. Owing to the high affinity of sulfide to Cu(II), the non-luminescent chemosensor can specifically and rapidly react with sulfide to yield the corresponding ruthenium(II) complex, [Ru(bpy)₂(bpy-DPA)]²⁺, accompanied by the remarkable luminescence enhancement. The dose-dependent luminescence enhancement of the sensor shows a good linearity with a detection limit of 20.7nM for sulfide anions. The novel luminescence sensor has a widely available pH range from 4.5 to 10 and an excellent response selectivity to sulfide only even in the presence of various other anions. Based on this chemosensor, a rapid, selective and sensitive luminescence method for the detection of sulfide anions in wastewater samples was established. The coefficient variations (CVs) of the method are less than 3.1%, and the recoveries are in the range of 90.9–108.5%.

Keywords: Heterobimetallic ruthenium(II)–copper(II) complex; Chemosensor; Sulfide anions; Luminescence sensing

Fabrication of a bilayer potentiometric phosphate biosensor by cross-link immobilization with bovine serum albumin and glutaraldehyde by Samuel B. Adeloju; Abdulazeez T. Lawal (pp. 89-94).

Chemical cross-linking of purine nucleoside phosphorylase (PNP) and xanthine oxidase (XOD) with glutaraldehyde (GLA) and bovine serum albumin (BSA) has been used to fabricate a stable and reliable bilayer potentiometric phosphate biosensor. The bilayer arrangement consists of an inner BSA–GLA layer and an outer BSA–GLA–PNP–XOD layer. The inclusion of the inner BSA–GLA layer improves the adhesion of the outer BSA–GLA–PNP–XOD layer and ensures stability of the phosphate biosensor. Established optimum conditions for immobilization of the enzymes in the outer layer and for reliable potentiometric measurement were 4.5% v/v GLA, 6.8% w/v BSA, XOD:PNP mole ratio of 1:8, and a film drying time of 30min. As little as 20μM of phosphate can be detected with the BSA–GLA/BSA–GLA–XOD–PNP bilayer biosensor with a linear concentration range between 40 and 120μM. The biosensor was very stable for 21 days, achieving a good reproducibility with a rsd of only 5.7% and, even after more than a month, the change in the initial potential value was only 10%.

Keywords: Phosphate; Potentiometric biosensor; Immobilization; Bovine serum albumin; Glutaraldehyde; Bienzyme system

Sensitive and selective DNA detection based on the combination of hairpin-type probe with endonuclease/GNP signal amplification using quartz-crystal-microbalance transduction by Yuehua Fei; Xiao-Yong Jin; Zai-Sheng Wu; Song-Bai Zhang; Guoli Shen; Ru-Qin Yu (pp. 95-102).

In order to develop a highly sensitive and selective piezoelectric transducer for the detection of DNA, the bio-recognizing probe is for the first time designed by introducing a hairpin structure and a recognition site for EcoRI into an oligonucleotide sequence and signal amplifiers are prepared by modifying gold nanoparticles (GNPs) with biomolecules, deepening the application and understanding of biomaterials. The piezoelectric transducer is prepared by immobilizing designed hairpin recognition probe onto the quartz-crystal-microbalance (QCM). In the absence of target DNA, the hairpin probe is removed from the QCM surface after exposure to endonuclease, inhibiting the subsequent signaling reaction. In contrast, introduction of target DNA can open the hairpin probe due to the probe/target hybridization, dissociating the cleavable double-stranded portion. In this case, even if being treated with endonuclease, the integrated hairpin probe is maintained. Subsequent introduction of GNPs modified with detection probes that can hybridize to the terminal sequence of hairpin probe results in a many-folds increase of the frequency response. Utilizing the proposed transduction scheme, the reliable target DNA detection can be accomplished. The detection limit of 2pM and dynamic response range for target DNA from 2 to 300pM are obtained. Furthermore, single-base mismatched DNAs can be easily identified. The developed proof-of-principle of a novel piezoelectric transduction scheme is expected to establish a potential platform for the disease-associated mutation analysis and DNA hybridization detection in biotechnology and medical diagnostics.

Keywords: DNA detection; Quartz crystal microbalance; Gold nanoparticle; Hairpin probe; Endonuclease

Determination of sodium benzoate by chiral ligand exchange CE based on its inhibitory activity ind-amino acid oxidase mediated oxidation ofd-serine by Haizhi Zhang; Li Qi; Juan Qiao; Lanqun Mao (pp. 103-109).

A novel quantitative approach for the determination of sodium benzoate (SB) was proposed by the kinetic study about its competitive inhibitory efficiency tod-amino acid oxidase (DAAO) activity with a chiral ligand exchange capillary electrophoresis (CE) method, in which the Zn(II)-l-prolinamide complex was chosen as a novel chiral selector. After the optimization of buffer pH and the chiral selector concentration this chiral ligand exchange CE method was employed to determine labeledd,l-Serine with good linearity ( r²≥0.995), efficient recovery (95.6–100.9%) and remarkable reproducibility (RSD≤1.2%). This chiral separation method was further used to observe DAAO activity through the determination ofd-Serine concentration variation after being incubated with DAAO and obtain the sigmoidal inhibitory curve of SB to DAAO activity. The ascending part of this inhibitory curve was linearly fitted in a limited range for SB from 2.0 to 200μM with an appropriate coefficient of determination ( R²=0.990). The linearity was then validated to be a promising method for the analysis of SB with the standout merits of high selectivity and adjustable detection range. Furthermore, this proposed method was used for the pharmacokinetics study of SB.

Keywords: Abbreviations; AAs; amino acids; CE; capillary electrophoresis; DAAO; d; -amino acid oxidase; Dns-; d; ,; l; -Ser; dansylated; d; ,; l; -Serine; d; -Ser; d; -serine; SB; sodium benzoate; Zn(II)-; l; -Prn; Zn(II)-; l; -prolinamideCapillary electrophoresis; d; -Amino acid oxidase; d; ,; l; -Serine; Inhibitory efficiency; Chiral ligand exchange; Sodium benzoate

Qualitative and quantitative analysis of chemical constituents in traditional Chinese medicinal formula Tong-Xie-Yao-Fang by high-performance liquid chromatography/diode array detection/electrospray ionization tandem mass spectrometry by Zhixiang Yan; Xinghao Yang; Jianbo Wu; Huai Su; Chen Chen; Yin Chen (pp. 110-118).

Tong-Xie-Yao-Fang (TXYF), a famous traditional Chinese medicine formula, has efficient effects on treatment of the diarrhea-predominant irritable bowel syndrome (D-IBS), a disease with high incidence worldwide. However, the active principles for this complex formula have not been fully explored so far. In this paper, high-performance liquid chromatography coupled with diode array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI-MS/MS) was applied for the qualitative and quantitative analysis of major chemical constituents in TXYF. Two monoterpene glycosides, one chromone and five polymethoxylated flavones were tentatively characterized based on the retention times, UV spectra and MS data. Fifteen compounds were unambiguously identified by comparison with reference standards. Constituents such as lactone and steroidal, which could not be found by single HPLC method due to the low content in the formula, were identified in this paper. Seven compounds (gallic acid, prim- O-β-d-glucosylcimifugin, paeoniflorin, cimifugin, naringin, hesperidin and 4′- O-β-d-glucosyl-5- O-methylvisamminol) were quantified by HPLC-DAD using a C18 column and gradient elution with acetonitrile and water–0.1% formic acid. The method exhibited intra- and inter-day precision of less than 2.35% and 3.14%, respectively. The LODs and the LOQs for the analytes were less than 0.47 and 1.82μgml⁻¹, respectively. The overall recoveries ranged from 96.82% to 102.47%, with the R.S.D. ranging from 1.17% to 3.94%. These results demonstrated that our present method was effective and reliable for comprehensive quality evaluation of TXYF. Meanwhile, the study might provide the chemical evidence for revealing the material basis of its therapeutic effects.

Keywords: Tong-Xie-Yao-Fang; Monoterpene glycosides; Polymethoxylated flavones; Quality evaluation; High-performance liquid chromatography coupled with diode array detection; Electrospray ionization tandem mass spectrometry

A diffusive sampling device for simultaneous determination of ozone and carbonyls by Shigehisa Uchiyama; Yohei Inaba; Naoki Kunugita (pp. 119-124).

A new diffusive sampling method for the simultaneous determination of ozone and carbonyls in air has been developed. In this method, silica gel impregnated with a mixture of trans-1,2-bis(2-pyridyl)ethylene (2BPE) and 2,4-dinitrophenylhydrazine (DNPH) is used as the absorbent; further, a porous sintered polyethylene tube (PSP-diffusion filter), which acts as a diffusive membrane, and a small polypropylene syringe (PP-reservoir) for elution of the analytes from the absorbent are used. The carbonyls present in air react with DNPH in the absorbent to form hydrazone derivatives. Concurrently, ozone in the air reacts with 2BPE to form pyridine-2-aldehyde, which immediately reacts with DNPH to form a pyridine-2-aldehyde hydrazone derivative. All the hydrazones derived from airborne carbonyls, including pyridine-2-aldehyde (formed from ozone), are completely separated and analyzed by high-performance liquid chromatography. The sampling rates of ozone (44.6mLmin⁻¹) and formaldehyde (72.0mLmin⁻¹) are determined by comparison with the rates obtained in an active sampling method. The sampling rates of other carbonyl compounds are calculated from the respective molecular weights according to a rule based on Graham's law. The calculated sampling rates agree with the experimental values. The DSD-BPE/DNPH method is advantageous because it is simple and allows for the simultaneous analysis of ozone and carbonyls.

Keywords: Diffusive sampler; Ozone; Carbonyl compounds; trans; -1,2-bis(2-pyridyl)ethylene; 2,4-Dinitrophenylhydrazine

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Analytica Chimica Acta (v.691, #1-2)

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Analytica Chimica Acta (v.691, #1-2)