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The paper presents new data on the activity coefficient at infinite dilution ( γ 13 ∞ ) for 29 various organic solutes: alkanes, alkenes, al-kynes, cycloalkanes, alcohols, ethers, ketones and aromatic hydrocarbons in two quaternary-ammonium based ionic liquids (quat-based ILs): didecyldimethylammonium perchlorate [DDA][ClO4] and didecyldimethylammonium tetrafluoroborate [DDA][BF4]. The activity coefficient at infinite dilution and physicochemical properties of two mentioned ionic liquids, were determined by inverse gas chromatography at four different temperatures: 308K, 323K, 338K and 353K. Additionally, on the basis of the specific retention volume ( V g 0 ) the Flory – Huggins interaction parameters ( χ ∞ ) were determined. In order to identify the fundamental interaction between solute and solvent inside the column, the partial molar excess enthalpies at infinite dilution (ΔH1E,∞) were calculated on the basis of experimental γ 13 ∞ values. The selectivity ( S i j ∞ ) and capacity ( k j ∞ ) at infinite dilution for a few different separation problems: hexane/benzene, cyclohexane/benzene and hexane/tetrahydrofuran were calculated from the experimental γ 13 ∞ values to evaluate the possible use of the ionic liquids studied as a new class of solvents in liquid-liquid extraction and in other extraction or microextraction methods. The values of the above-mentioned parameters were compared and discussed taking into regard the chemical structures of both quaternary ammonium-based ionic liquids, including the same cation and their interactions with the organic solute.

A needle trap device (NTD) was developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) from liquid samples followed by determination by gas chromatography–mass spectrometry ...

Chemical constituents of cryptic species detected within the liverwort Aneura pinguis were identified using headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). Fibre coating with divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) was used. A total of 48 samples of A. pinguis were analysed. The studied plants were identified genetically based on barcode DNA sequences and represented three cryptic species (A, B and F) of A. pinguis. Cryptic species A and B are genetically diverse; both represent three evolutionary lineages: A1, A2, A3 and B1, B2, B3, respectively. The cryptic species F that was recently detected is not diverse. The most characteristic compounds in analysed samples were sesquiterpene hydrocarbons (up to 17.7% for A1; 15.7% for A2; 20.6% for A3; 7.7% for B1; 2.0% for B2; 3.7% for B3; 10.2% for F), oxygenated sesquiterpenoids (up to 68.0% for A1; 54.7% for A2; 52.6% for A3; 63.5% for B1; 88.7% for B2; 82.7% for B3; 78.8% for F), and linear aliphatic hydrocarbons (up to 14.8% for A1; 1.1% for A2; 12.1% for A3; 6.9 for B1; 5.2% for B2; 1.1% for B3; 7.0% for F). The dominant compound in the studied samples was pinguisone. The second dominant compound present in the tested plant material was deoxopinguisone, except for lineage B2, where only a small relative concentration of this compound was found. A high content of deoxopinguisone in cryptic species A (lineages A1, A2 and A3) was accompanied by the presence of isopinguisone and methyl norpinguisonate, whereas these two compounds were not detected in cryptic species B (lineages B1 and B3) and F. The chemical compounds detected in the studied samples of A. pinguis were subjected to multivariate statistical analysis. The results showed that the chemical composition depends mainly on the genotype of the plant and slightly on the habitat. However, there was no clear correlation between the volatile compounds and the date of collection of the studied plants.

Microextraction techniques are widely applied for sample preparation to gas chromatographic analysis of target compounds in samples with a complex matrix. Recently, needle-based microextraction techniques have been developed in order to improve performance of the extraction. The main advantages of these techniques are miniaturization, automation, high performance, environmentally friendliness and on-line coupling with analytical instruments. This review focuses on the three needle-based microextraction techniques including solid-phase dynamic extraction (SPDE), in-tube extraction (ITEX) and needle trap device extraction (NTD). The core of the aforementioned techniques is an extraction phase protected in the stainless steel needle. The application of the sorbent-protected needle extraction techniques for the gas chromatographic analysis of environmental, biological and food samples is discussed. The fundamental aspects and development over the years are also summarized.

Analysis of trace compounds in complex matrices requires a preliminary step of sample preparation. From among widely used methodologies, microextraction techniques have become increasingly important as they tend towards being environmentally friendly. The needle trap (NT) extraction is a relatively new and promising technique which combines sampling, sample preparation and sample introduction. The core of the needle trap device is a suitable sorbent material packed inside the needle, that determines selectivity and efficiency of the method. In recent years, the effort towards improvement of needle trap extraction performance has led to development of new extraction media with higher selectivity and better adsorption properties, which may facilitate preconcentration of the target analytes. In this work, we present a review on the trends in development of sorbent materials used in the needle trap device including fibrous media, commercially available materials as well as sorbents prepared for special applications. This review also describes recent developments in the needle trap devices such as needle geometries, sorbent packing procedure and sampling methodologies. Comparison of needle trap extraction and solid phase microextraction (SPME) is presented to demonstrate the robustness of the former.

The main goal of the study was to determine the compounds released from titanium into the overlying oral mucosa and the other metals found in two-stage dental intra-osseous implants. The determined concentration of the metals was as follows: titanium from 1.7 to 13.1 μg g−1, nickel 10.0–0.8 μg g−1, aluminum 5.3–100.5 μg g−1, zinc 16.1–118.8 μg g−1, and copper 0.3–13.6 μg g−1, respectively. Additionally, we also present the results of experiments carried out to determine the release of metal ions from two implant systems (Astra and Dentium) into a solution of lactic acid (1%). The quantitative analysis of the metal ions was performed by means of an emission spectroscope by inductively coupled plasma ICP-OES. Studies were also carried out on the surfaces of different implant systems, including: Osteoplant, Astra, Dentium, SKY, Neoss as well as Biomet. The research involved the use of scanning electron microscopy to determine the chemical composition and quality of these systems.

This paper describes our research on the synthesis of the sorbent with chemically bonded ketoimine groups, and, furthermore, using this sorbent in the SPE technique to extract and preconcentrate trace amounts of metal ions in water samples. Surface characteristics of the sorbent were determined by elemental analysis, NMR spectra for the solid phases (29Si CP MAS NMR), and analysis of pore size distribution of the sorbent and nitrogen adsorption-desorption. The newly proposed sorbent with ketoimine groups was applied for the extraction and preconcentration of trace amounts of Cu (II), Cr (III) and Zn (II) ions from the water from a lake, post-industrial water and purified water unburdened back to the lake. The determination of the transition-metal ions was performed on an emission spectroscope with inductively coupled plasma ICP-OES. For the batch method, the optimum pH range for Cu (II) and Cr (III) extraction was equal to 5, and Zn(II)–to 8. All the metal ions can be desorbed from SPE columns with 10 mL ...

New macrocyclic stationary chemically bonded phases were synthesized and tested in gas chromatography conditions. The complexes of 1,4,8,11-tetraazacyclotetradecane with Cu(II) and Co(II) were bonded to the silica support through the (3-chloropropyl)triethoxysilane reactant. The packings obtained were analyzed by diffuse-reflectance ultraviolet–visible spectroscopy (DRUV–Vis), differential thermal gravimetry (DTG), porosimetry, and elementary analysis. Preliminary study of the novel silica gas chromatography (GC) stationary phases containing cyclam complexes was carried out using packed 1/8 in. i.d. columns. The study was conducted on: cyclic, linear and branched olefins, aromatic hydrocarbons and ethers. Characterization of interactions between the compounds mentioned and new stationary phases was based upon analysis of Kovats retention indices (I), difference between retention indices for two phases (ΔI), and molecular retention indices (ΔMe). Results have shown that the new stationary phases interact sufficiently strongly with molecules of high electron density and can be applied in capillary gas chromatography for the analysis of light hydrocarbons.

This review is devoted to the application of metal complexes as column packings and liquid stationary phases in gas chromatography. Particular attention is paid to the stationary phases with nitrogen-containing functional groups (e.g., amine and ketoimine) and beta-diketonates on the modified silica surface. The review also concerns the results of the research on metallomesogenes and chiral stationary phases. The factors influencing the retention mechanism in complexation gas chromatography are discussed. Practical application of the metal chelate-containing chromatographic packings for analytical separation of organic substances is considered.

This work describes some results of identification and determination of bisphenol A (BPA) in powdered milk by applying the gas chromatography. To determine BPA contents in the milk and to reduce the matrix interference associated with the constituents of the powdered milk, we performed the following activities. First, we ultra-centrifuged the dissolved milk solutions. Next, we preconcentrated the analyte in the supernatant using a C(18) and new sorbent with chemically bonded ketoimine group solid phase extraction column. Finally, we used gas chromatography for the determination of BPA in the samples under study. A recovery of bisphenol A from spiked milk samples was also performed, with recovery result located at 91% +/- 3%/94% +/- 2%.

Sediment samples were analysed for mercury and methylmercury content in different parts of the bottom sediment of Swarz edzkie Lake, which were influenced by different external pollution sources. The results of determination with two methods of mineralization using two separate media (HNO3/H2O2 and HF) were compared. The accuracy of the studied methods was analysed using certified reference material IAEA 405 of river sediment. The recovery of mercury was satisfactory and ranged from 97.5 to 98.8%. Methylmercury compounds in the studied sediments were found in limited concentrations. Their concentrations ranged from 0.26 to 58.1 μg kg−1, i.e. 1.0–7.4% of the total mercury content. The depth profile displayed high values of both total and methylmercury content at a depth of 10–20 cm, related to the heavy pollution of the lake in the 1980s. Canonical analysis displayed the relationship of both total mercury and methylmercury concentrations with organic matter and phosphorus content in bottom sediments.

New adsorbents for capillary complexation GC have been proposed. The adsorbents contain free ketoimine groups which enable binding copper(II) and chromium(III) chlorides. The adsorbents obtained have been characterised by elemental analysis, differential scanning calorimetry and electron spin resonance. The specific interactions between the adsorbent and adsorbate molecules have been characterised by retention parameters (retention index - I, specific retention volume - Vg, molecular retention index - deltaMe). Attempts were also made at separating mixtures of olefins.

The preparation of adsorbents for capillary CGC has been described. The adsorbents have a free ketoimine group which enables to bound copper(II) and nickel(II) chlorides. The prepared adsorbents have been characterised by such physico-chemical techniques as elemental analysis, differential scanning calorimetry (DSC) and electron spin resonance (ESR), in addition to the characterisation performed by using chromatographic methods. The nature of adsorbate-adsorbent interactions was interpreted for the group of compounds studied. An attempt has been also made at solving the structure of surface complex formed.

A new method for immobilisation of an adsorbent on the wall of a capillary column ensures high thermal and mechanical stability of the resulting coating. The method can be applied to a variety of adsorbents of natural or synthetic origin. Its effectiveness is illustrated by results obtained for coating with modified silica or molecular sieve 13X.

Structural study of the azo compound obtained as a result of diazotization and coupling of 8-amino-naphthalene-2-sulfonic acid (Cleve's acid), has been performed by the spectroscopic methods 1 H NMR and FTIR. UV–vis spectra of 8-amino-5,8′-azo-bis-naphthalene-2-sulphonic acid (CA-CA) were measured in water environment at different pH values and at a constant ionic strength. On the basis of the NMR, FTIR as well as on the grounds of a comparison of the experimental UV–vis spectra with those obtained by the MM/ PM5 in water followed by ZINDO method calculation, geometry of the CA-CA molecule in water solution has been proposed. Moreover, the value of the first dissociation constant of the dye has been determined (2.75×10 −2 ).

In the presented work, copper(II) and chromium(III) complexes chemically bonded to silica surface were prepared and used in gas chromatography. Chlorides of these metals were bonded to the silica surface by the use of the ketoimine group originally from 2-(3-triethoxysililpropylimino)-3-(n-butyl)-pentanone-4. Packings obtained in such way were investigated to evaluate their usefulness in the analysis of aliphatic and aromatic halogenated hydrocarbons as well as ethers, thioethers and ketones. Moreover, packings were subjected to elemental analysis and differential scanning calorimetry (DSC), thus some retention parameters were determined to characterize specific interactions between bonded metal and adsorbate molecules. Attempts were also made to separate some mixtures of the nucleophilic compounds.

Results of studies on stationary phases containing copper(II), nickel(II) and cobalt(II) chloride chemically bonded via cyano—or thiol groups are presented. The retention parameters—i.e. retention factor (k), retention index (I) and molecular retention index (ΔMe) and specific retention volume (Vg)-enabled the characteristics of specific interaction between aromatic and cyclic hydrocarbons and metal complexes chemically bonded to stationary phases to be determined.

The study reported in this work concerns the use of copper and chromium complexes, chemically bonded to silica, in gas chromatography. Chlorides of these metals were bonded to the support through amino groups from [3-(trimethoxysilyl)propyl]diethylenetriamine. The packings were tested in order to verify their usefulness in the analysis of aliphatic and aromatic nucleophilic compounds. The retention parameters characterising specific interactions of the bonded metal with adsorbate molecules, such as: retention factor (k), retention index (I), specific retention volume (Vg), and molecular retention index (ΔMe), were determined. For comparison, similar measurements were conditioned on a packing with no bonded metal.

The use of polysiloxanes with cyano or thiol groups as stationary phases for complexation gas chromatography is discussed. The polymers were obtained via polycondensation followed by polymerisation of the corresponding dichloro- or dimethoxy-silanes. Both the phases were modified by bonding transition metal chlorides with were modified by bonding transition metal chlorides with cyano (CuCl2 or CoCl2) and thiol groups (NiCl2 or CoCl2). The phases were examined in order to determine their application to the analysis of ethers, thioethers and ketones. Due to the presence of lone electron pairs on oxygen or sulphur atoms, the compounds should be capable of specific interacting with the electron-withdrawing centre of the liquid stationary phases. A number of retention parameters (retention indices, molecular retention indices and specific retention volume) were determined, which allowed characterisation of specific interactions between the bonded metal and the compound analysed. The results also enabled assessment of the influence of the structure of the compounds on their retention. The measurements were also carried out for the phases with free SH and CN groups as reference phases. The work demonstrates that the phases obtained may be useful for effective separations.

Investigations were carried out on capillary columns coated with liquid stationary phases possessing cyano (3-cyanopropylmethylpolysiloxane) and thiol (3-mercaptopropylmethylpolysiloxane) groups. These phases were modified by bonding CuCl2 and CoCl2 to cyano groups or NiCl2 and CoCl2 to thiol groups. The modified phases were examined in order to assess their usefulness for the analysis of aliphatic and aromatic halohydrocarbons. A number of retention parameters (I, ΔMe, Vg), which allow characterisation of the specific interactions between the bonded metal and the halohydrocarbon molecule, were determined for the columns both with and without the metal. The separations performed show that the columns with bonded metals are applicable for the practical analysis of the halohydrocarbons.

Complexes of Cu(II) chemically bonded to silica surface are studied and used in gas chromatography. Copper(II) chloride in a tetrahydrofuran solution was bonded to the support via iminoketonate groups. The packing obtained in such a way was investigated to evaluate its usefulness in the analysis of aliphatic and aromatic halogenated hydrocarbons as well as ethers and thioethers. A number of retention parameters was determined (retention factor – k , specific retention volume – V g , molecular retention index – Δ M e ) which enabled to characterize specific interactions between bonded metal and adsorbate molecules. A packing containing no bonded metal was also investigated and served as a reference. Attempts were also made to separate some mixtures of the nucleophilic compounds.

The synthesis of liquid stationary phases with mercaptopropylmethyl polysiloxane containing cations of Ni 2+ or Co 2+ , bonded to the polymer via thiol groups, is described. Columns of 30 m×0.53 mm were coated with these stationary phases (film thickness of 0.5 μm). The columns are thermally stable up to 250°C. The average molecular masses of the prepolymer (805) and the polymer (10 612) were calculated. The Grob test was also performed. Retention factors ( k ), retention indices ( I ) and specific retention volumes ( V g ) were found for the compounds of McReynolds series. The obtained polysiloxanes were characterised by means of spectroscopic techniques (UV–Vis, IR). The former technique has enabled to confirm the formation of a metal-phase bond, while the other provided information on polysiloxane chain length increase. Concentrations of metals in the phases containing metal complexes (Ni 2+ /SH – 7.34×10 −3 ; Co 2+ /SH – 4.52×10 −2 ) were determined by a voltammetric method. The stationary phases prepared were capable of interacting specifically with nucleophilic compounds.

The synthesis of liquid stationary phases with cyanoproppylmethyl polysiloxane containing cations of Cu2+ or Co2+ which were bonded to the resulting polymer via cyano groups is described. Columns of 30m×0.53 mm were coated with these stationary phases (film thickness of 0.5 μm.). The characteristics of the polysiloxanes obtained were determined by the use of spectroscopic techniques (UV-vis, IR). The thermal stability of the columns was established and the average molecular mass of the polymer was calculated. The Grob test mixture was also used to evaluate the columns.

Results are presented of studies of new types of packings for gas chromatography which contain nickel(II) and cobalt(II) chlorides and nickel(II) acetylacetonate chemically bonded via β-diketonate groups to a silica surface. Taking into account the ability of the metals in the chlorides and acetylacetonate to interact with compounds showing electron-donor properties, the study was performed using such adsorbates as aliphatic linear and branched hydrocarbons. The study allowed the determination of the influence of structure and configuration of adsorbate molecules on their retention and the definition of the usefulness of thus prepared packings in chromatographic analysis. The obtained results point to selectivity of the packings to the compounds which contain π electrons. Moreover, to determine the influence of the type of functional group bonded with hydrocarbon chain of a given silane on charge-transfer interactions, the obtained results were compared with those for the packings in which nickel(II), cobalt(II) chlorides and nickel(II) acetylacetonate were bonded with silica via diphenylphosphine groups.

The determination of thallium in human hair samples by differential pulse anodic stripping voltammetry after microwave digestion has been presented. Hair samples were collected from the vertex of the scalps of donors who were employed in factories manufacturing lead-acid batteries. The results show that permanent contact with an environment polluted by lead makes it possible to absorb very large amounts of thallium, which is present in this environment only as an impurity of lead. The study also shows that absorption of thallium by workers is a few times ‘better’ than that of lead.

Prior to determination of Pb, Cd, Zn and Cu by differential pulse anodic stripping voltammetry microwave digestion has been evaluated for the decomposition of human hair samples using a HNO3H2O2 mixture. The efficiency of the decomposition, and the accuracy and precision of the proposed procedure was studied using a human hair standard. Hair samples were collected from the vertex of the scalps of donors who were employed in factories manufacturing lead-acid batteries, nickel-cadmium batteries and gas (petroleum) vending station workers. The results show that, in all cases, permanent contact with the polluted environment makes it possible to absorb very large amounts of lead or cadmium, simultaneously depressing zinc absorption. Results of a study on the content of the above elements in human hair of persons who had had no work place contact with these elements are also presented.

The synthesis of some new packings for complexation gas chromatography (CGC) is proposed in this article. These packings contain acetylacetonates and hexafluoroacetylacetonates of nickel(II) and cobalt(II), which are chemically bonded to a silica gel via β-diketonate groups. The effect of the structure and the configuration of some adsorbates (olefins, cyclic and aromatic hydrocarbons) on the retention of these compounds is determined. Moreover, the usefulness of the packings in the analysis of hydrocarbons is described. The results show the good applicability of the tested packings as well as their high selectivity towards compounds which contain π-electrons.

The solubility parameter δ2 and dispersive force parameters were estimated for a group of chemically bonded stationary phases. Selected physico-chemical parameters were determined by means of inverse gas chromatography. The influence of the structure of the liquid phases examined on their properties was evaluated and discussed.

The paper reports a new group of adsorbents obtained by modification of silica surface with silane containing 3-benzylketoimine groups with bonded Cu(II) and Ni(II) chlorides. The adsorbents obtained were subjected to a chromatographic study to establish the type of adsorbate-adsorbent interactions for aliphatic and aromatic halogenated hydrocarbons used as adsorbates. The following retention parameters were determined: retention factor (k), Kovats retention index (I), specific retention volume (V g), and molecular retention index (ΔM e). Values of the molecular retention index were subjected to complex statistical analysis providing qualitative relations between the adsorbates’ properties and spatial structure and their retention. It was observed that bonding of chlorides of Cu(II) and Ni(II) with the ketoimine groups resulted in an increase of the retention index and the molecular retention index indicating an increase of the adsorbate-adsorbent interaction in comparison with the reference column coated with silane including a 3-benzylketoimine group without transition metal chlorides. Along with the observed increase of the adsorbate-adsorbent interaction, larger difference between the retention indices was observed for both halogenated compounds. This indicates a positive influence of the introduced transition metals on the selectivity of the adsorbate-adsorbent interactions of the examined columns.

The quantitative structure-retention relationship (QSRR) was used to predict Kováts retention indices of forty-three volatile olefins on the chemically bonded stationary phase, containing 1,4,8,11-tetraazacycloteradecane (cyclam) complexes of copper(II) chloride. Retention indices were correlated with eleven descriptors derived from structures of olefins optimised using the molecular mechanics force field calculations (MM2). Descriptors were generated with the use of quantitative structure-activity relationships (QSAR), semi-empirical Austin Model 1 methods (AM1), and obtained from physicochemical databases. Five well-correlated models were built, with predictive coefficients of determination (R 2) values of 0.993 and 0.995. The dielectric energy (DE) descriptor was identified as being as important as the polarizability (P) descriptor in the process of separation of unsaturated olefins on stationary phases containing metal complexes. The DE index proved to be decisive in distinguishing between the geometric cis and trans isomers of the tested compounds.

A piece of fused-silica fibre coated with silica modified with ketamine-groups was used as a solidphase microextraction (SPME) fibre and its efficiency in the qualitative and quantitative analysis of volatile organic compounds released from coloured overprinting on DVDs was evaluated. The effect of the parameters that can affect the SPME procedure, such as extraction time, extraction temperature, desorption temperature, was investigated to determine the analytical performance of this novel fibre in the qualitative and quantitative analyses of organic compounds. The optimised procedure was applied to the qualitative and quantitative analyses of organic compounds released from coloured overprinting on DVDs. The limit of detection of 4-methoxyphenol (mequinol) was 88 × 10−3 μg mL−1, while the limit of quantification (LOQ) was calculated as ten times the baseline noise, i.e. 3.1 × 10−1 μg mL−1. The proposed fibre was used successfully for preconcentration of the volatile organic compounds from the gaseous phase of DVD samples.

Column packings containing β-diketonate chelates of copper(II) and nickel(II) chemically bonded with silica surfaces can be used to separate nucleophilic species by metal complex formation. The investigated sorbents are capable of selectively retaining unsaturated linear and cyclic hydrocarbons. The packing properties depend on both the metal and the ligand. The influence of electronic effects on the retention of donors is discussed.

The applicability of silica gels for the application in solid-phase extraction was tested. Silica was modified with ketoimine groups. Surface characteristics of the modified silica were determined by elemental analysis, NMR spectra of solid phases (29Si CP MAS NMR), analysis of pore size distribution of the silica support, and nitrogen adsorption-desorption. Newly proposed sorbents with ketoimine groups were applied in the preconcentration of trace amounts of the Cu (II) ions from lake water, post-industrial water, and demineralized water unburdened back to the lake.

In many EU countries and outside the EU, besides the addition of pure methyl ester B-100 to diesel oil, mixtures of methyl esters are also added to fuel. To be used as fuel, methyl esters must meet certain requirements, one of which is a certain level of acylglycerols. The paper presents results of determination of acylglycerols in diesel oil dotted with fatty acid methyl esters. The compounds were determined by gas chromatography using a high-temperature capillary column DB-5HT, made by J&W, and 1,2,3-tricaproylglycerol as internal standard. The analytical method proposed permits not only determination of acylglycerols, but also differentiation if the FAME added originated from pure vegetation oil or used cooking oil.

The new stir-bar coating based on silica gel modified with ketoimine groups was applied to the preconcentration of phenolic endocrine disruptors and heavy metal ions such as Cuii, Criii and Niii in water samples followed by determination using LD-GC/MS and ICP-OES, respectively.

The presented work is devoted to Porasil C silica, with organic compounds bonded to its surface and capable of electron-donor-acceptor (EDA) interactions. These packings are a good base for studying interactions among stationary phases and the adsorbate molecules showing electron-donor properties. The presented work concentrates on the phases containing ketoimino groups at their surface. Copper and chromium chlorides were bonded through these to the surface. Physicochemical characteristics of the obtained packings were determined by the use of elemental analysis, differential scanning calorimetry (DSC) and inverse gas chromatography. We examined the influence of the surface modification on the retention parameters of the nucleophilic compounds.

The separation properties of poly[copper(II) di-n-hexylphosphinate] as a column packing were studied and homologous series, isomers and compounds with close boiling points were separated. The separation of impurities in α-methylstyrene is demonstrated as an example of contamination analysis.

The separation properties of alkaline-earth metal di- n -hexylphosphinates in relation to hydrocarbons have been described. The possibilities of specific interactions of unsaturated hydrocarbons with alkaline-earth metals are noted. A number of chromatographic separations on magnesium di- n -hexylphosphinate are reported.

This part of this review discusses the applications of adsorbents containing transition metals in gas chromatography, and the methods permitting the calculation of the stability constants of weak complexes between transition metals and organic compounds from gas chromatographic data.