Standard Column Research Articles

Effects of counterion type on selective arsenic removal process combining standard anion exchange resin with electrocoagulation for polluted groundwater

This study achieved the highly selective removal of trace arsenic (As) from groundwater (110 μg L−1 As) by the standard anion exchange resin (AER) column process during long-term exhaustion–regeneration cyclic operation by optimizing the sulfate equivalent fraction (0.97 or 0.875) in sulfate-chloride or sulfate-bicarbonate binary brine (chloride or bicarbonate as counterion). No significant (<5%) or low (maximum: 25%) sulfate removal from the feedwater were stably observed during the 20 or 21 exhaustion–regeneration cycles without brine treatment or replacement, when <10 μg L−1 As was consistently observed in the product water. Furthermore, this study demonstrated the selective As removal from As-rich sulfate-chloride or sulfate-bicarbonate spent brine by aluminum (Al)- or iron (Fe)-based chemical coagulation or electrocoagulation process. Fe-based electrocoagulation (9-cm interelectrode distance, 0.50 mA cm−2, 15 min) and sulfate-chloride binary brine are finally recommended after metal dosage, sludge production and residual metal concentration among them were compared. No electrocoagulation took place in the sulfate-bicarbonate spent brine even at a current density of 3 mA cm−2 because of high bicarbonate concentration that formed passivation film on the anode surface. Finally, a combined process including a standard AER column and spent brine electrocoagulation was developed to achieve the stability and high As-selectivity of 114 exhaustion–regeneration cycles.

Seismic Performance of H-Shaped Steel Column with Replaceable Slip Friction Joints

Based on the concept of structural damage control, a beam-through steel frame system with continuous columns was constructed. Replaceable connectors were set at both ends of an H-shaped steel column to connect the beam with high-strength bolts. In this study, three specimens were designed and fabricated, that is, a standard H-shaped column, an H-shaped column with replaceable connectors at the bottom of the column, and an H-shaped column with replaceable connectors at both ends. Low-circumferential reciprocal loading tests were carried out to analyse the influence of the location of replaceable slip friction joints on the seismic performance of steel columns. Results showed that the H-shaped steel column with replaceable slip friction joints at both ends slipped during the loading process, as expected. The test hysteresis curve was full, and the skeleton curve did not drop significantly; thus, the column demonstrated satisfactory seismic performance. The steel column was not significantly damaged or deformed, and connectors could be reset and replaced after an earthquake to achieve post-earthquake repair. The effect of the thickness of the horizontal limbs of the connectors on the seismic performance of the H-shaped column with replaceable connectors at both ends was analysed using finite element simulation. The results revealed that the reasonable setting of the thickness of the horizontal limbs of the connectors can ensure the frictional energy dissipation capacity of the connectors and achieve the expected damage control.

Microflow size exclusion chromatography to preserve micromolar affinity complexes and achieve subunit separations for native state mass spectrometry

For high throughput native mass spectrometry (MS) protein characterization, it is advantageous to desalt and separate proteins by size exclusion chromatography (SEC). Sensitivity, resolution, and speed in these methods remain limited by standard SEC columns. Moreover, the efficient packing of small bore columns is notoriously difficult. SEC sensitivity is inherently limited because solutes are not focused into concentrated bands and low affinity native complexes may dissociate on column. Recent work evaluated the suitability of crosslinked gel media in small bore formats for online desalting. Here, small bore format online SEC for native MS studies is again investigated but with alternative materials. We systematically studied the utility of diol and hydroxy terminated polyethylene oxide (PEO) bonded 1.7 µm organosilica particles as packed into 1 mm ID stainless steel (SS) hardware and hardware treated with hydrophilic hybrid surface technology (h-HST). For the equivalent diol-bonded particle and hardware, UV limits of detection (LODs) were reduced 32 to 89% with a microflow separation (15 µL/min) on a 1 × 50 mm column as compared to a 4.6 × 150 mm high-flow separation (300 µL/min) at the same linear velocity. Run times were also shortened by 45%. A switch from SS to h-HST hardware led to a significant reduction in secondary interactions and a corresponding improvement in detection limits for trastuzumab, myoglobin, IgG and albumin for both UV and MS. Coupling of the small bore columns to multichannel microflow emitters resulted in 10 to 100-fold gains in MS sensitivity, depending on the analyte. MS LOD values were significantly reduced into the low attomole ranges. Columns were then evaluated for their effects on the preservation of complexes, including concanavalin A, in its apo and ligand-bound states, and three therapeutically relevant noncovalent systems previously undetected on large column formats. The results suggest that the detection of large complexes by SEC is not just a function of sensitivity but is directly affected by chemical secondary interactions. The ability to detect 0.1 to 1 MDa complexes, with between 1 and 40 micromolar dissociation constants, represents a critical advancement for high-throughput native MS workflows as applied to the analysis of therapeutics.

Effect of donor blood storage on gel column crossmatch in dogs.

Compared with fresh blood, stored equine donor blood results in spurious tube crossmatch incompatibilities. Interpretation of blood crossmatch results is considered subjective. We aimed to determine if the duration of canine donor blood storage impacts compatibility testing using a standard gel column crossmatch and evaluate interobserver variation in the interpretation of crossmatch results. Observational study. Whole blood segments were obtained from 23 canine packed red blood cell (RBC) units for use in crossmatches after storage for 0, 7, 14, 21, 28, and 35 days. Major and minor crossmatches were performed using serum and RBCs, respectively, from two to three healthy "recipient" dogs per unit. All crossmatch results were interpreted by four observers, of whom three were blinded. All major crossmatches (n=61) were compatible on day 0 and remained compatible through day 35 of storage. All minor crossmatches (n=69) were compatible at all time points, except for five donor pairs with 1 to 3+ agglutination. Repeat testing of these five donor pairs confirmed crossmatch incompatibilities on days 0 through 35, with no change in the degree of incompatibility over time. There was substantial agreement among four observers in determining compatibility (κ=0.94) and scoring incompatibility (κ=0.76). The current practice of performing canine crossmatches with whole blood segments stored for up to 35 days is acceptable, with no spurious changes in compatibility expected over time. The substantial interobserver agreement suggests that the gel column is suitable for performing canine crossmatches in a laboratory setting with multiple personnel.

Unusually Chemoselective Photocyclization of 2-(Hydroxyimino)aldehydes to Cyclobutanol Oximes: Synthetic, Stereochemical, and Mechanistic Aspects.

Photocyclization of carbonyl compounds (known as the Norrish-Yang reaction) to yield cyclobutanols is, in general, accompanied by fragmentation reactions. The latter are predominant in the case of aldehydes so that secondary cyclobutanols are not considered accessible via the straightforward Norrish-Yang reaction. A noteworthy exception has been reported in our laboratory, where cyclobutanols bearing a secondary alcohol function were observed upon UV light irradiation of 2-(hydroxyimino)aldehydes (HIAs). This reaction is here investigated in detail by combining synthesis, spectroscopic data, molecular dynamics, and DFT calculations. The synthetic methodology is generally applicable to a series of HIAs, affording the corresponding cyclobutanol oximes (CBOs) chemoselectively (i.e., without sizable fragmentation side-reactions), diastereoselectively (up to >99:1), and in good to excellent yields (up to 95%). CBO oxime ether derivatives can be purified and diastereomers isolated by standard column chromatography. The mechanistic and stereochemical picture of this photocyclization reaction, as well as of the postcyclization E/Z isomerization of the oxime double bond is completed.

Post-earthquake serviceability assessment of standard RC bridge columns using computer vision and seismic analyses

Modern design codes ensure a large displacement capacity and prevent total collapse for bridges under earthquakes. However, this performance objective is usually attained at the cost of damage to target ductile members. For conventional reinforced concrete (RC) bridges, columns are usually the main source of ductility during an earthquake in which concrete cover, core, and reinforcement may damage, and the column may experience a large permanent lateral deformation. Visual inspection is currently the preferred method of bridge assessment after an event. Nevertheless, sending inspectors to all affected bridges is time consuming and logistically challenging. An alternative method may save time, costs, and lives. The main goal of the present study was to accelerate post-earthquake assessment of standard RC bridge columns using computer vision and seismic analyses. Standard columns are those that are designed following seismic requirements. To achieve the project goal, a new quantitative definition was proposed for RC bridge column damage states suited for computer programming, the most comprehensive experimental database of standard RC bridge columns consisting of 290 specimens was compiled, then the database was statistically analyzed to relate the proposed column damage states to displacement demands. Furthermore, an artificial intelligence enabled software was developed to quickly detect RC bridge column damages, to comment on the column damage state, and to tag the column. A framework was proposed to assess the serviceability of standard RC bridge columns after earthquakes.

Purification of Recombinant Eukaryotic MAO A and MAO B Utilizing the Pichia pastoris Expression System.

Procedures are described for the heterologous expression and purification of the mitochondrial-bound enzymes human and rat monoamine oxidases A and B and zebrafish MAO in the yeast Pichia pastoris. Enzyme expression is under control of a methanol oxidase promoter and similar procedures have been developed for the preparation of membrane particles and detergent solubilization of the functional enzymes. Similarities and differences are described in the procedures for purification of the respective enzymes using standard column chromatographic techniques to provide enzyme yields in the range of 100-300mg from 1L of cell culture.

Molecular biology analysis of ABO blood group variants caused by natural chimaerism.

The chimaerism phenomenon constitutes a significant mechanism underlying ABO phenotype discrepancies; however, its detection has technical challenges. In the current study, we explored different techniques to establish the chimaeric status of ABO blood types. Fifteen individuals with possible chimaeric ABO blood type, as suggested by standard tube or column agglutination method and RBC adsorption-elution test, were enrolled in the study. The red blood cells from 11 investigated subjects showed mix-field agglutination with anti-A or anti-B in blood typing; weak A or B antigens on the other four individuals' RBCs were detected by adsorption-elution tests. The genetic study was conducted with PCR-SSP genotype, DNA sequencing of the ABO gene, STR analysis and ddPCR. The genetic chimaeric status was confirmed in four (27%) individuals by SSP test alone. The ABO gene sequencing identified an additional ABO allele and enabled chimaerism detection in 10 (67%) subjects. The STR analyses established the chimaerism status in 13 (87%) individuals. In the two cases where neither of the tests mentioned above had positive findings, the ddPCR was adopted, and microchimaerism, with an extremely low degree of chimaerism (0.77% and 0.12%), was revealed. The ddPCR revealed the unequal haplotypes (29.5% B vs. 70.5% O) in one subject and distinguished this B/O-O/O chimaera from certain B subgroups (B/O genotype without any mutation) like B3 . The ABO blood type chimaerism can be genetically established by comprehensive molecular methods, including PCR-SSP/DNA sequencing, STR and ddPCR, which is particularly sensitive for the detection of microchimaerism.

A cleavable self-aggregating tag scheme for the expression and purification of disulfide bonded proteins and peptides

The production of correctly folded, disulfide bonded proteins in high yields remains a technological challenge, especially for the commonly used expression system Escherichia coli. This work provides a standardizable method based on cleavable self-aggregating tag (cSAT) scheme that enables the facile production of a series of traditionally challenging disulfide bonded proteins and peptides. The yields of the six targets were in the range of 3 to 89 mg/L at the shake flask scale. Further scale up of human growth hormone resulted in a yield of 2.6 g/L in a 30-L fermenter. This cSAT scheme allows the correct folding of proteins and peptides in an aggregated form during expression, and can be combined to a standard two-step column purification to achieve high purity and high activity products. This promises a generally applicable platform for the production and purification of proteins and peptides with markedly reduced development time and cost.

Detection of Preclinical Orthostatic Disorders in Young African and European Adults Using the Head-Up Tilt Test with a Standardized Hydrostatic Column Height: A Pilot Study

Arterial hypertension (AH) remains the most common disease. One possible way to improve the effectiveness of the primary prevention of AH is to identify and control the preclinical orthostatic disturbances that precede the development of AH. The aim of the study was to determine the feasibility of a new protocol for the head-up tilt test (HUTT) with a standardized hydrostatic column height for the detection of asymptomatic orthostatic circulatory disorders and their racial differences in young African and European adults. Methods. In total, 80 young healthy adults (40 African and 40 European) aged 20–23 years performed the HUTT with a standardized hydrostatic column height of 133 cm. The hemodynamic parameters were recorded using a Task Force Monitor (3040i). The cardio-ankle vascular index (CAVI) was measured using a VaSera VS-2000 volumetric sphygmograph. Results. The baseline and orthostatic hemodynamic changes in both racial groups were within normal limits. Orthostatic circulatory disturbances were not detected in 70% of the European participants and 65% of the African participants; however, preclinical orthostatic hypertension, which precedes AH, was detected using the new HUTT protocol in 32.5% of the African participants and 20% of the European participants. The baseline CAVI was higher in the European group compared to the African group. Conclusion. The results of this study showed the feasibility of the detection of preclinical orthostatic disturbances in young adults and the detection of their racial differences using the HUTT protocol, providing the use of a standard gravity load. Further study on the evolution of preclinical orthostatic disturbances and their relation to increased vascular stiffness is necessary among large samples.

How Journalists and Civil Society View Gender Portrayal in Editorial Cartoons in Kenya’s Daily Nation and Standard Newspapers

Diverse views by scholars, policy makers as well as readers of newspapers and magazines, point to one critical issue that the media have of late become conduits for gender stereotyping not only in Kenya but the world over. This fact has been affirmed by public uproar against specific media houses in recent years after publishing cartoons that appeared offensive to sections of society. In some cases, such protests and reactions were very violent and claimed lives besides causing the destruction of property. Hinged on the Agenda setting theory, this paper refers to Kenya’s Daily Nation and Standard newspapers cartoon column in seeking to highlight what journalists and civil society consider to be the position of gender portrayed in editorial cartoons and whether by extension these cartoons subtly or unconsciously promote gender bias and stereotypical overtones. The qualitative case study was guided by the interpretivist philosophical paradigm. Besides the secondary data drawn from the two dailies, semi-structured interviews that targeted cartoonists, human rights, and gender activists from six purposely selected organizations were applied and analysed. The study finds bias and increased stereotypical overtones occasioned by a lack of resolve by the two media houses to adequately embrace gender sensitivity focus in the manner editorial cartoonists portray both men and women in the news. To cure the gender portrayal bias in the selected cartoons, there is need for specific in-housed editorial guidelines that will guide its creators.

Practical and concise synthesis of nucleoside analogs.

Nucleoside analogs are valuable commodities in the development of antisense oligonucleotides or as stand-alone antiviral and anticancer therapies. Syntheses of nucleoside analogs are typically challenged by a reliance on chiral pool starting materials and inefficient synthetic routes that are not readily amenable to diversification. The novel methodology described in this protocol addresses several longstanding challenges in nucleoside analog synthesis by enabling flexible and selective access to nucleoside analogs possessing variable nucleobase substitution, D- or L-configuration, selective protection of C3'/C5' alcohols and C2' or C4' derivatizations. This protocol provides direct access to C3'/C5' protected nucleoside analogs in three steps from simple, achiral starting materials and is described on both research (2.8 g) and process (30 g) scales for the synthesis of C3'/C5'-acetonide protected uridine. Using this protocol, proline catalyzes the fluorination of simple heteroaryl-substituted aldehyde starting materials, which are then directly engaged in a one-pot enantioselective aldol reaction with a dioxanone. Reduction, followed by intramolecular annulative fluoride displacement, forges the nucleoside analog. The three-step parent protocol can be completed in ~5 d by using simple mix-and-stir reaction procedures and standard column chromatographic purification techniques.

Preparation of a zeolite imidazole skeleton-silica hybrid monolithic column for amino acid analysis via capillary electrochromatography.

We developed a novel, convenient and low-cost one-pot strategy for preparing a zeolitic imidazolate framework-8 (ZIF-8)-silica hybrid monolithic column by adding ZIF-8 directly to a polymer solution of the silica matrix. The simulated stationary phase and monolithic column prepared under optimal conditions were characterized using X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis nitrogen physisorption and zeta potential. The results obtained confirmed the successful introduction of ZIF-8 into the silica monolithic column, and the prepared monolithic column exhibited good permeability and physicochemical stability. A capillary electrochromatography method was developed based on a ZIF-8-silica hybrid monolithic column through which 15 mixed amino acids, 4 neutral compounds, 4 nipagin esters and 2 chlorinated fungicides were separated in 14, 5, 7 and 6min, respectively, under optimal conditions. The relative standard deviations retention times and column efficiencies in run-to-run, day-to-day and column-to-column varied in the ranges of 1.90%-2.21%, 2.13%-2.51% and 3.08%-6.65%, respectively, which demonstrated that ZIF-8-silica hybrid monolithic column exhibited satisfactory reproducibility and stability. The incorporation of ZIF-8 into a silica monolithic column is a promising method for preparing novel monolithic columns composed of a metal-organic framework.

Toward Super Temporal Resolution by Suppression of Mixing Effects of Electrons

The theoretical temporal resolution limit of silicon (Si) image sensors is 11.1 ps. The super temporal resolution (STR) is defined as a frame interval less than this limit. The temporal resolution of burst image sensors is significantly affected by “mixing” of signal electrons traveling from different starting positions. For example, the penetration depths of photons incident to a surface of a photodiode (PD) disperse exponentially, resulting in mixing of the photoelectrons from different depths at the other end, which causes a distribution of the arrival times. The temporal resolution is proportional to the standard deviation of the arrival time. Toward STR imaging, this article proposes measures to suppress various mixing phenomena during the travel of the signal electrons: 1) a germanium (Ge) PD for visible light to practically eliminate the effect of vertical mixing caused by the distribution of the penetration depth; 2) an inverted pyramid PD to efficiently suppress the horizontal mixing, keeping a 100% fill factor; 3) a standard column PD with negative potential on the vertical walls to squeeze the trajectory bundle of electrons falling on the guide gate on the front side; and 4) a resistive guide gate to linearize the potential profile to maximize the horizontal drift velocity to minimize the mixing together with the squeezed electron bundle.

HBIM LIBRARY DEVELOPMENT FOR A DORIC TEMPLE COLUMN

Abstract. The growing interest within the construction industry in the preservation, rehabilitation, and conservation of heritage-value buildings has led to the implementation of Historic Building Information Modelling (HBIM). Especially in Greece, where the number of historical buildings is considerably large, having efficient and standardized processes of Cultural Heritage management and conservation becomes a prerequisite. The rigorously accurate representation of old constructions requires specific geometric modelling processes in order to generate the necessary relevant libraries of parametric objects. This paper describes the development of a parametrized library for the main parts of a Doric Temple to be used for introducing such parts in an HBIM system. Moreover, to verify the correctness of the parametrized column an application is performed in which the dimensions of a real column are compared with the dimensions of the standard one. The study improves the potential of the BIM process for its application to buildings with distinctive architecture in the context of the preservation or conversion of heritage buildings. In first section the term HBIM is explained and its usefulness to cultural heritage (CH) is justified. Section 2 describes previous attempts to create HBIM libraries for historic structures. After that, the construction of parametric model, which was created with visual programming Dynamo, is presented. Finally, the efficiency of the adjustment of a standard column to a given point cloud is described and in the end the results of the application are compared and discussed.

Front Cover: Comparison of the separation of proteins of wide‐ranging molecular weight via trilobal polypropylene capillary‐channeled polymer fiber, commercial superficiously porous, and commercial size exclusion columns

DOI: 10.1002/jssc.202100891 The reversed-phase (RP) separation of proteins, without size-exclusion contributions, is affected on capillary-channeled polymer (C-CP) fiber stationary phases. Polyester C-CP fibers are demonstrated to perform the rapid RP separation of peptides and proteins ranging in molecule weight of 1.44-to-660 kDa. Comparisons with commercial RP superficially porous and size exclusion columns designed for protein separations show that the across-the-board separation quality realized by the fibers is superior to the other column formats, with column material costs being far less than the standard columns.

Studies on copper (II) removal from aqueous solutions by poly (3,4-ethylene dioxythiophene) polystyrene/sulphonate Sn (IV)tungstatophosphate (PEDOT: PSS/STP) nanocomposite

ABSTRACT To address the pollution of heavy metal ions in water resources, a new adsorbent poly (3,4-ethylene dioxythiophene) polystyrene/sulphonate Sn (IV)tungstatophosphate (PEDOT: PSS/STP), made of organic and inorganic materials, was effectively produced using a sol-gel bottom-up approach. The surface morphology, elemental composition and, structural features of the synthesised nanocomposite were investigated by various spectroscopic techniques such as XRD, TEM, FESEM, EDAX, and FTIR, whereas the surface charge measurement (Zeta potential) and ion exchange capacity (IEC) were determined by dynamic light scattering (DLS) analysis and standard column method, respectively. The batch experiment technique was utilised to determine the parameters for analysing the adsorption behaviour for the elimination of Cu (II) ions from aqueous solution. The kinetics of the adsorption process were investigated using pseudo-first-order and pseudo-second-order kinetic models, while the thermodynamics were assessed using Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin thermodynamic models. The Langmuir isotherm was best fit to experimental data for adsorption of Cu (II) ions from an aqueous solution with a maximum adsorption capacity of 85.05 mg g−1 at pH 7.0 at different temperatures, whereas kinetic adsorption characteristics were best suited to the pseudo-second-order model. The thermodynamic parameters ΔHo, ΔGo, and ΔSo were determined and represent Cu (II) adsorption onto PEDOT: PSS/STP is an endothermic, spontaneous, and chemisorption reaction. Furthermore, even after five adsorption-desorption cycles, the adsorption capacity of PEDOT: PSS/STP nanocomposite adsorbent was around 70%, demonstrating that the regeneration capability of PEDOT: PSS/STP nanocomposite adsorbent was excellent, which is the fundamental characteristic to select the proper adsorbent.

Preparation and application of porous organic cage capillary electrochromatographic chiral column

多孔有机笼(POCs)是一种新型的具有稳定有序三维空腔结构的多孔材料。通过2-羟基-1,3,5-均苯三甲醛与1R,2R-1,2-二苯基乙二胺发生席夫碱的缩合反应,合成了一种具有羟基功能基团的单一手性POCs材料;将其均匀涂敷在毛细管壁上制成色谱柱,利用电色谱柱成功拆分了二氢黄酮、吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺4种手性化合物。探究了分离电压、缓冲溶液浓度及其pH值等因素对手性拆分的影响,获得了4种手性物质在POCs色谱柱上的最佳拆分条件。实验研究表明,二氢黄酮、吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺获得优化分离效果所需的工作电压分别为13、14、14和12 kV;二氢黄酮适宜Tris-H3PO4缓冲溶液浓度为0.075 mol/L,吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺适宜Tris-H3PO4缓冲溶液浓度为0.100 mol/L; 4种手性物质得到最佳分离效果时的pH值均为3.51。二氢黄酮、吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺均达到基线分离,分离度分别为2.99、2.10、2.58和3.59。该POCs色谱柱还成功拆分了o,m,p-碘苯胺、o,m,p-硝基苯胺两种位置异构体。该研究表明POCs手性电色谱柱具有良好的手性识别能力,是一种优秀的手性分离材料,具有很大的电色谱手性分离应用前景。

Leaching of Titanium Dioxide Nanomaterials from Agricultural Soil Amended with Sewage Sludge Incineration Ash: Comparison of a Pilot Scale Simulation with Standard Laboratory Column Elution Experiments.

Nanoscale titanium dioxide (nTiO2 (Hombikat UV 100 WP)) was applied to sewage sludge that was incinerated in a large-scale waste treatment plant. The incineration ash produced was applied to soil as fertilizer at a realistic rate of 5% and investigated in pilot plant simulations regarding its leaching behavior for nTiO2. In parallel, the applied soil material was subject to standard column leaching (DIN 19528) in order to test the suitability of the standard to predict the leaching of nanoscale contaminants from treated soil material. Relative to the reference material (similar composition but without nTiO2 application before incineration) the test material had a total TiO2 concentration, increased by a factor of two or 3.8 g/kg, respectively. In contrast, the TiO2 concentration in the respective leachates of the simulation experiment differed by a factor of around 25 (maximum 91.24 mg), indicating that the added nTiO2 might be significantly mobilisable. Nanoparticle specific analysis of the leachates (spICP-MS) confirmed this finding. In the standard column elution experiment the released amount of TiO2 in the percolates between test and reference material differed by a factor of 4 to 6. This was also confirmed for the nTiO2 concentrations in the percolates. Results demonstrate that the standard column leaching, developed and validated for leaching prediction of dissolved contaminants, might be also capable to indicate increased mobility of nTiO2 in soil materials. However, experiments with further soils are needed to verify those findings.

Retention indices for naturally-occurring chiral and achiral compounds on common gas chromatography chiral stationary phases

Chiral gas chromatography columns were initially developed for enantiomeric separations, however, they are increasingly being used for routine analyses of natural samples which also include many achiral compounds. Retention index (RI) data have been essential in the identification of natural compounds using standard columns when authentic standards are not available, but scarce RI information exists for chiral columns. In this work, we present linear RI data for 81 compounds (chiral and achiral) commonly found in biological samples for the two most common chiral stationary phases, Cyclodex-B and CycloSil-B, calculated with an alkane hydrocarbon series. In addition, we compared the resolution of various isomer pairs between the two chiral stationary phases and found better overall performance with CycloSil-B. Finally, we tested the applicability of our data set by calculating RI values for numerous compounds in leaf extracts of two Monarda fistulosa chemotypes on both columns and found good agreement. We discuss the relevance of chiral chromatographic retention data in a chemical ecology framework and call for the development of a comprehensive chiral RI database.