Application Finder

Portable Raman spectroscopy is an invaluable tool in the study of archaeological sites, allowing for in situ analysis which minimizes the impact of such studies on important cultural sites. The flexibility of the use of a fiber optic probe and tripod-mounted video microscope with a light weight instrument reduces the need for sampling, and increases the ability to make representative measurements over what can be very large sample areas. The information content of Raman spectroscopy aids in the understanding of the materials used in the construction and restoration of important archaeological sites, and in understanding the degradation that is occurring which should aid in preservation and restoration work.

At a crime scene, a police officer collects a fiber sample that may prove to be invaluable evidence in identifying a criminal or exonerating an innocent person. In recent years, Raman spectroscopy has been studied extensively for forensic fiber analysis because of the high selectivity of Raman signatures, non-destruction nature of the test, and the ability to conduct the analysis without any sample preparation. The Raman spectrum can be measured directly on fabrics or fibers mounted on glass slide with very little interference from the mounting resin or the glass.

Two electrometric methods for determining the pH value of papers with homogeneous and heterogeneous pH cross-sections are described.

After the degradation of biological samples (e.g. milk, wool, etc.), it is often important to know the cystine/cysteine ratio. This Application Bulletin describes the simultaneous, polarographic determination of the two amino acids. The determination is performed in perchloric acid solution at the DME. Samples with a high protein content require that the determination is performed in an alkaline solution.

The present Application Bulletin contains NIR applications for the determination of important parameters for pulp and paper quality analysis. Each application describes the instrument that was originally used for the analysis, as well as the system recommended for the analysis and the results that were achieved thereby.

The present Application Bulletin describes applications that use near-infrared spectroscopy. Each application describes the used and alternatively deployable spectrometer as well as analysis conditions and results and, where available, information on feasibility studies.

Determination of chromium in leather waste solutions in the range between 1000 and 30,000 ppm.

Determination of chlorite by direct thermometric titration with standard sodium thiosulfate solution. The procedurewas applied originally to the determination of chlorite in hide treatment solutions.

Determination of sodium, potassium, and silica values in sodium and potassium silicates.

This Application Note describes how NIR spectroscopy can be used to determine residual lignin content in wood pulp. Using the major absorbance peaks of both lignin and cellulose in the second derivative spectra, the residual lignin content in wood pulp can be monitored during paper production.

Near-infrared spectroscopy (NIRS) is ideally suited to monitor the hardwood and softwood content in pulp and paper products.The herein described method bases on the fact that the changes in hardwood and softwood content are reflected in the intensity of the absorption bands of cellulose. A linear least-squares regression on second derivative spectra provide results that correspond very well with those of conventional laboratory determinations. With NIRS, an analytic method is available that provides results in real time.

This Application Note shows how purity, degree of substitution and water content of carboxymethyl celluloses (CMC) can be determined conveniently and rapidly in a single measurement with Vis-NIR spectroscopy.

This Application Note shows the determination of the ratio of cotton linter to pulp in cellulose samples with Vis-NIR spectroscopy. This linter-pulp ratio is an important characteristic in the paper industry which, unlike with elaborate wet-chemistry methods, can be determined quickly and conveniently with Vis-NIR spectroscopy.

This Application Note shows the fast and parallel determination of water content and pH value in crude tall oil samples using near-infrared spectroscopy (NIRS). Crude tall oil is an important byproduct of pulp production in the power process. NIRS is an efficient alternative to conventional laboratory methods: It permits rapid raw material inspection, process monitoring and final product checking.

In this Application Note, Vis-NIR spectroscopy (Vis-NIRS) is used to determine six wood pulp properties in a single measurement: kappa number, applied density, freeness, breaking strength, buckling strength and tensile strength.

This Application Note demonstrates how the OMNIS NIR Analyzer Solid quickly determines the cotton content in various textile products within just 30 seconds.

Determination of glycolic acid, formic acid, glutaric acid, acetic acid, propionic acid, and butyric acid in paper industry process water using ion-exclusion chromatography with suppressed conductivity detection.

The Kraft process is the dominant pulping process in the pulp and paper industry with the highest chemical recovery efficiency. In order to run each part of the papermaking process optimally, constant quality checks and analyses should be performed. This Process Application Note illustrates the straightforward online analysis of alkali (active, effective, total titratable alkali (TTA)), carbonate, hydroxide, sulfide and the causticizing degree (CE%) in pulping liquors using a 2060 Process Analyzer from Metrohm Process Analytics.

To optimize the wet-spinning process in the viscose/rayon production, it is crucial to measure sulfuric acid and zinc. H2SO4 and ZnSO4 are analyzed using a potentiometric titration and colorimetric measurement technique. Results are automatically validated against a known standard solution to guarantee preset control limits.

The size of the indigo molecule makes it difficult to dye synthetic fibers, but the large pores of cellulose (such as in cotton) accept it readily. Indigo is insoluble in water, so it must first be reduced to the water-soluble leuco-indigo form by sodium hydrosulfite in a strong alkaline bath. Good circulation within the bath is imperative for consistent dye coverage, but care must be taken not to introduce any oxygen. Fabrics must be oxidized between dips in the dye bath in order to set the indigo within the pores of the fibers, but multiple dips are necessary for darker, uniform coverage. Many parameters need to be monitored and controlled to ensure high quality of the end product: the pH value for proper NaOH (alkali) dosage, the concentrations of both hydrosulfite and indigo, as well as the temperature of the bath and even the redox potential.

Determination of chloride, sulfite, sulfate, and thiosulfate in a process water using anion chromatography with conductivity detection after chemical suppression and subsequent UV/VIS detection.

Inline Ultrafiltration is a proven sample preparation technique for samples that are slightly or massively contaminated with particles, algae or bacteria. Filtration and injection are coupled and fully automatic. As a rule, 100 or more samples can be filtered through a single membrane. Service life is extended – even with highly contaminated tannery effluent – to more than 300 injections because the filter membrane is rinsed again once more after the analysis with the aid of the Dosino backflush.

Determination of chromium(VI) (chromate) in leather extract using anion chromatography with UV/VIS detection after post-column reaction (PCR) and inline dialysis for sample preparation.

Determination of sulfide and thiosulfate in a process water using anion chromatography with UV/VIS detection after chemical suppression and conductivity detection.

Determination of sulfide in a raw vanadate solution using anion chromatography with UV/VIS detection.