Analytical Instrument Documents

The phthalates used as plasticizers in polymer resins are endocrine-disrupting substances that are a risk to human health. Therefore, the use of phthalates is limited by various government agencies. In the field of electrical equipment manufacturing, diisobutyl phthalate (DIBP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), and di-2-ethylhexyl phthalate (DEHP) are regulated by the European Union’s Restriction of Hazardous Substances (RoHS) Directive. The use of DBP, BBP, DEHP, di-n-octyl phthalate (DNOP), diisononyl phthalate (DINP), and diisodecyl phthalate (DIDP) in toys and baby care products is regulated in Europe, the United States, China, and Japan. Phthalates subject to regulation are being replaced with alternative substances. However, it is known that phthalates tend to contaminate the manufacturing process and storage areas. Some alternative materials (e.g., tris-2-ethylhexyl trimellitate [TOTM]) may contain regulated components (e.g., DEHP) as impurities. In this report, PVC cables for commercial products using alternative substances as plasticizers were analyzed by the pyrolysis/thermal desorption–gas chromatography–mass spectrometry (Py/TD-GC-MS) method described in IEC 62321-8: 2017 [1]. Any phthalates discovered were quantified, and spectral information was collected for other detected compounds.

Electron ionization (EI) is the most commonly used ionization technique in gas chromatography–mass spectrometry (GC-MS). This hard ionization technique (70eV) provides excessive energy to organic compounds that results in highly reproducible fragment ions with relatively high ion intensities. As a result, EI databases have been created that help with identifying the compounds of interest. Despite this ability to do database searches, some compounds (alkanes, alcohols, etc.) do not produce abundant molecular ions, thus making it difficult to differentiate similar compounds from each other. By contrast, photoionization (PI) is a soft ionization technique that uses a vacuum ultraviolet (VUV) light source to provide ionization energies in the range of 8–10eV. This range is optimal for the soft ionization of common organic compounds which have an ionization energy in the range of 8–11eV. This low ionization energy results in stronger molecular ion signals and less fragmentation than for EI. Combining an EI library search with PI molecular ion information can improve the accuracy of the qualitative analysis results. In this work, we report on the qualitative analysis of styrene foam (Styrofoam) before and after photodegradation, using pyrolysis (Py)-GC/MS with an EI/PI combination ion source.

Thermogravimetry (TG) is used to measure weight changes of samples under programmed heat conditions. A system combining thermogravimetry/differential thermal analysis (TG/DTA) with mass spectrometry (MS) is called a TG-MS system, and can be used for both qualitative and quantitative mass spectral analysis of evolved gas from the TG furnace. The TG-MS technique can also be used to analyze the thermal-decomposition process. This application note shows an example of comparative analysis of mechanical-pencil leads of different performances, grades, and manufacturers. These leads are made by baking a mixture of graphite and resin, and then dipping it in oil for hardness and smoothness. Since the resin is carbonized and baked out, the lead is composed of only carbon and oil. In this application note, we show TG-MS analysis results for these mechanical-pencil leads using a “STA2500 Regulus” system (NETZSCH) and a gas chromatography–quadrupole mass spectrometry (GC/QMS) “JMS-Q1500GC” system (JEOL).

The Direct Insertion Probe (DIP) option permits rapid analysis of solid or liquid samples without gas chromatography. Samples contained in a disposable glass capillary are introduced with the DIP directly into the Q1500 ion source through a vacuum lock. The DIP temperature can be programmed for fast or slow heating to desorb or pyrolyze samples for analysis. In this example, we use the DIP to detect additives in a low-density polyethylene storage bag.

Fermenters used for home beer brewing are fitted with an airlock consisting of a liquid barrier that permits the fermentation gases to escape while preventing contamination from atmospheric microbes. Large volumes of carbon dioxide are produced during the most vigorous stages of fermentation, which can occur as early as the first 24 hour period after an ale yeast is added (pitched) to the sweet liquid (wort) produced from barley during the initial mashing step. The gases emitted from the airlock can have a pleasant aroma that can be quite distinctive during the initial stages of fermentation. Solid-phase microextraction (SPME) combined with gas chromatography/mass spectrometry (GC/MS) was used to determine the volatile components contained in the fermentation gas.

Electron ionization (EI), a hard-ionization technique that generates many fragment ions, is the most widely used ionization technique in gas chromatography–mass spectrometry (GC-MS). Since EI mass spectra have good reproducibility, qualitative analysis is possible by comparing an EI mass spectrum of a sample with that of the known compound recorded in the database. However, sometimes EI mass spectra lack molecular ions, which are of key importance to molecular-weight (MW) determination and correct compound assignment. Soft ionization is a useful way to determine MW. The JEOL JMS-Q1500GC offers two soft-ionization techniques: chemical ionization (CI) and photoionization (PI). In this application note, the MW information of diethyl phthalate and n-tetradecane were estimated from measurement results using both of these soft-ionization techniques.

The AccuTOF makes it very easy to obtain exact mass measurements and determine elemental compositions. The mass spectra shown below were acquired with the electrospray ion source operated in negative-ion mode. The mass calibration was acquired the previous day in positive-ion mode. After changing the mass spectrometer polarity and retuning, a stearic acid impurity (present in the methanol) was used as a single-point drift correction “lock mass” to determine the elemental composition of the analyte peak at m/z 256.06242 and the palmitic acid impurity at m/z 256.23104. The error was less than 0.002 u.

JEOL recently introduced a new-generation LC/TOFMS system (the “AccuTOF™”)with a wider dynamic range than conventional LC-TOF MS systems. The increased dynamic range of the AccuTOF provides qualitative and quantitative analysis with the increased accuracy and resolution of an LC/TOFMS system. While the AccuTOF preserves the benefits of TOF MS, such as high sensitivity, high resolution and high mass accuracy, it also features a durable orthogonal API source with long-term stability and easy maintenance. Here, we describe the features of the orthogonal API source. We also demonstrate the ability to operate the AccuTOF for an extended period in the presence of a nonvolatile phosphate buffer often used for LC Analysis.

Sudan dyes are red dyes that are used for coloring solvents, oils, waxes, petrol, and shoe and floor polishes. They are considered to be carcinogens and teratogens. Due to this fact, the US and the EU do not permit the use of these colors as food additives. However, in some countries, these dyes are still occasionally used in order to intensify the color of bell pepper and chili powders. Here, we describe a simple LC/TOF-MS method for sudan dyes I, II, III, and IV analysis.

It has been a decade since Dodonov and his colleagues [1] first announced the electrospray ionization time-of-flight mass spectrometer (ESI-TOF MS). Their initial findings have been enhanced by Standing and others [2,][ 3], and it has been recently reported that a large TOF MS system achieved a mass resolution exceeding 10,000 [4]. Encouraged by the results acquired by Dodonov and Standing, some of the MS manufactures have produced bench top ESI-TOF MS systems. However, most of these commercial models have a narrow dynamic range and are unfit to quantitative analysis because they use a TDC (Time-to-Digital Converter) as a data acquisition system. Their applications were mainly in qualitative analysis with exact mass measurement, and are limited in such fields as environmental studies and chemical dynamics that require only qualitative analysis. Because of detector saturation, these systems only show good mass acuracy when operated within a limited analyte concentration range.

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