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For a variety of reasons, the water content of chocolate is of crucial importance and has to be accurately determined. This poster compares an automated version of the Karl Fischer titration (KFT) using the sequential addition of various solvents with the widespread manual titration at elevated temperatures using a chloroform/methanol mixture. The water contents determined by the two procedures show excellent agreement. However, manual titration requires laborintensive sample preparation, the side reactions are difficult to quantify and hazardous halogenated solvents have to be used. In contrast, automated KFT is straightforward, uses non-hazardous solvents, allows to quantify the side reactions and is easily applicable to water determinations in sugar- and fat-containing matrices.

In modern days, a new breed of energetic (explosive) materials is emerging. Traditional aromatic nitrates are still in use, but there is dire need of analytical techniques for energetic materials in the chemical class of peroxides, azo etc. This presentation will demonstrate the use of a modern HPLC system with traditional detector (DAD) and also coupled with mass spectrometry for the analysis of abovementioned various classes of energetic materials.

This poster presents a highly reproducible procedure for the determination of the sodium contribution of acid-extractable organic species in Bayer process liquor. The precision of the method is estimated to be 0.2% RSD.

Metrohm's iColumns are the first IC columns that are equipped with a data chip that stores freely definable data, fixed column data as well as data entered by the MagIC NetTM software. Any relevant information such as column type, standard parameters, maximum pressure, etc. can be called up at any time. Analysis data continuously entered by the MagIC NetTM software guarantees a complete column and GLP-compliant surveillance irrespective of the IC system in which the column is operated. The MagIC NetTM software surveys the critical column data and indicates any infringement of limits.

By using the 800 Dosino and the 849 Level Control as the only additional devices, Metrohm`s intelligent ion chromatography (IC) systems - the 850 Professional IC and the Compact IC family - can be easily extended to perform any unattended inline eluent preparation. Fully controlled by MagIC NetTM, the 849 Level Control monitors the eluent level while the Dosino performs all dosing and liquid handling tasks. Consecutive injections of a 250-µg/L standard over approximately 20 days revealed an excellent retention-time stability. After more than 800 consecutive injections, relative standard deviations for anions (F-, Cl-, NO2-, Br-, NO3-, PO43-, SO42-) and cations (Li+ , Na+, NH4+, K+, Ca2+, Mg2+) were smaller than 0.55 and 0.41%, respectively. In the case of a 24-hour sequence, retention-time precision for anions and cations was better than 0.09 and 0.08%, respectively. The presented inline eluent preparation system increases the retention-time reproducibility and allows the determination of anions and cations over a one-month period without manual eluent preparation.

By means of IC-ICP/MS, different valence states of arsenic and mercury in the form of inorganic and organic species can be sensitively and unambiguously identified in one single run. Determination of common arsenic species in biological matrices is straightforward and can be performed down to the sub-ppb level.Species transformations of mercury that occur during several sample preparation techniques, however, require the use of specific isotope dilution mass spectrometry (SIDMS). This work illustrates the decisive advantage that Environmental Protection Agency (EPA) Method 6800 (SIDMS) offers for studying the transformations of mercury species during sample preparation of fish tissue samples. Because of the unique features and benefits of EPA Method 6800, it is expected that utilization of SIDMS will increase and that this valuable tool for optimizing and validating trace-metals-speciated sample preparation will gain much wider acceptance by analytical chemists.

Comparative measurements show that the new Metrosep C 4 cation column has even better separation characteristics than the previous Metrosep C 2 and Metrosep Cation 1-2 column types. The Metrosep C 4 column has a clearly improved peak shape which leads to a better separation of the individual peaks. Using Metrosep C 4 the number of theoretical plates per meter was noticeably higher than that obtained on the Metrosep C 2 or C 1-2 column. Additionally for standard cations transition metals and amines, the Metrosep C 4 column shows better results with respect to peak shape, peak height, resolution and asymmetry factor. The clearly improved resolution of the C 4 column with its narrow and high peaks achieves baseline separation for six standard and six transition metal cations. Analysis times and peak areas obtained with the C 4 column are in the same range as those obtained with its predecessors.As a result of the latest production methods and materials, the promising Metrosep C 4 column excels by an outstanding separation performance for complex mixtures comprising standard cations, transition metal cations and amines.

This poster presents a straightforward ion chromatographic determination of HF, HNO3, short-chain organic acids and H2SiF6 in etching bath samples. Standard ions such as fluoride, nitrate, acetate and sulfate are determined via suppressed conductivity detection while dissolved silicate is spectrophotometrically detected in the same run after downstream post-column reaction (PCR) as molybdosilicic acid. Analytical results of several commercial HF-HNO3-H2SiF6 mixtures obtained by ion chromatography (IC) and titration showed good agreement, which confirms the applicability of the presented «dual» detection IC method for controlling the composition of acidic texturing baths.

The combination of 850 Professional IC, 858 Professional Sample Processor, Dosino and MagIC NetTM software offers a variety of automated ion chromatographic sample preparation and calibration techniques available as an anion, cation or dual channel system. Calibration is straightforward and requires only one multi-ion standard.Inline calibration allows the calibration of any standard concentration in the ppt range by using one single stable standard solution at the ppb level. By using a preconcentration column and switching the valves one, two or more times different calibration concentrations at the ultra-trace level can be created with unprecedented reproducibility. The inline preconcentration technique uses a pre-concentration column and is ideally suited for trace analysis in complex matrices, especially when combined with matrix elimination. Besides facilitating the preparation of g/L to ng/L calibration graphs Metrohm`s intelligent techniques are capable of logical decision making. While Metrohm`s intelligent Partial Loop technique (MiPT) allows samples with a wide concentration range to be injected without previous manual dilution, the intelligent inline dilution technique, after the first sample injection, compares peak areas, calculates, if necessary, the dilution factor, dilutes and automatically re-injects the sample. The presented inline techniques allow the rationalization of the time-consuming, error-prone and cost-intensive manual preparation of standard solutions. They guarantee that the determined sample concentrations always lie within the calibration range. Higher sample throughputs as well as lower analysis costs and improved data reliability are achieved.

The analytical challenge treated in the present work consists in the determination of chloride, phosphate and sulfate in the presence of difficult sample matrices that interact with the stationary column phase or even render it unusable. Metrohm`s patented stopped-flow dialysis coupled to the new 881 Compact IC pro ion chromatograph overcomes these drawbacks. Two standard solutions covering the concentration ranges 1.0…3.6 mg/L and 10…36 mg/L as well as two samples, an ultra-high temperature (UHT) processed milk and a baby milk powder, were characterized in terms of analyte concentration, relative standard deviation, calibration quality, carryover and recovery rates. While the five-point calibration curves yielded correlation coefficients (R) better than 0.9999, carryover (between two subsequent injections of a concentrated sample and a blank) was less than 0.49%. Recoveries for the low (10…36 mg/L) and high standard concentrations (1.0…3.6 mg/L) were within 91…99% and 94…100%, respectively. Automated compact stopped-flow dialysis is a leading-edge sample preparation technique that ensures optimum separation performance by effectively protecting the column from detrimental matrix compounds.