App Notes

Comparison of silica-based versus polymer-based Amino columns

Endocrine-disrupting compounds (EDCs) encompass a variety of chemical classes, including drugs, pesticides, polymer additives, coatings materials, personal consumer products, industrial by-products, and pollutants. There is worldwide concern over long-term environmental exposure to EDCs leading to serious health effects, including a range of reproductive problems such as reduced fertility, male and female reproductive abnormalities, skewed male/female sex ratios, brain and behavior problems, impaired immune functions, and various cancers.

The 875 KF Gas Analyzer is a tiamoTM-controlled system for determining the water content in gases and liquefied gases. The analyzer module consists of a pipe system including four software-controlled magnetic valves, which allow the control of the sample gas and the rinsing gas flow. Additionally, an oven, a mass flow controller, the titration vessel with indicator and generator electrode (with diaphragm), and a coulometer are included in the module.

Chiral amino acids represent a vast array of diverse structural components that are essential for development of peptide-derived drugs. Our recently introduced zwitterionic stationary phases, CHIRALPAK® ZWIX(+) and ZWIX(-), can serve as important tools to help accelerate drug discovery and development of target peptides. As potential therapeutics, peptides offer higher specificity and lower toxicity profiles than small molecules. However, peptides are susceptible to degradation by natural proteases. This can be easily overcome by synthesising peptides that contain D-amino acids, which are not recognised by proteases, thereby making the peptides resistant to the degradation. Analyses of underivatised D/L-amino acids, as building blocks of peptide- derived drug targets, are therefore necessary to ensure enantiomeric purity of the final products. Examples of separations of di- and tri-peptides, utilising CHIRALPAK ZWIX stationary phases, are shown in Figure 1 and Figure 2.

The "Statistical Compare" option available in ChromaTOF software allows the user to view statistical comparisons as a data processing step for groups of samples. The groups of samples are divided into different subsets or classes. ChromaTOF software aligns the data for the specified group of samples from the data processed peak tables. Upon completion of peak alignment, statistical information (such as minimum, maximum, average, relative standard deviation, etc.) on various peak properties (such as peak height, peak area, retention time, etc.) can be viewed in the Compound Table generated by Statistical Compare. The software will also compare statistical information from each class and between classes. Additionally, "Fisher Ratios" can be calculated from the Compound Table for each analyte. The Fisher ratio is a statistical calculation that can be used to discover the unknown chemical differences among known classes of complex samples. Statistical Compare results can also be exported as a .csv file and applied to third party software programs for supplemental data reduction such asmultivariate analysis.

Citrus oils are widely used in consumer products. Contamination with pesticides is of particular concern because the citrus oils are derived from the outer portion of the fruit. GCxGC-TOFMS provides for analysis for many pesticides in citrus oils with minimal sample preparation. This work shows the ability of this technique to sufficiently separate these pesticides from the citrus oil components, to provide confirmation of identity, and to quantify these residues over several orders of magnitude concentration, reaching as low as part-per-billion levels.

Fragrances are complex mixtures that are part of everyday life. From cosmetics to household products, chemicals that produce scent are present at various levels, but little is known about their composition since fragrance formulas are considered trade secrets. New health concerns about allergic reactions caused by chemicals present in fragrances of synthetic or natural origin (it is estimated that 1 to 2% of the population has allergies to fragrance) have led to an increased interest in the analysis of perfumes. The 7th Amendment of the EuropeanCosmetics Directive requires the declaration of the listed 26 "fragrance allergens" (24 defined volatile substances and 2 botanicals) if they exceed specified levels. As a result, a project was initiated at the end of 2001 within the International Fragrance Association (IFRA) to develop a method for the analysis of "fragrance allergens", with the purpose of defining a way to determine and regulate their presence.

Endocrine-disrupting compounds (EDCs) encompass a variety of chemical classes, including drugs, pesticides, polymer additives, coatings materials, personal consumer products, industrial by-products, and pollutants. There is worldwide concern over long-term environmental exposure to EDCs leading to serious health effects, including a range of reproductive problems such as reduced fertility, male and female reproductive abnormalities, skewed male/female sex ratios, brain and behavior problems, impaired immune functions, and various cancers.

The complex nature of crude oil demands analytical solutions and instrumental methods that will separate and identify the complex chemical profile as well as characterize key chemical functional group class differences between complex samples. Comprehensive two-dimensional gas chromatography (GCxGC) expands the peak capacity of the chromatographic separation thereby increasing resolution and analyte characterization for complicated samples. Time-of-Flight mass spectrometry (TOFMS) offers continuous full range non-skewed mass spectral information and fast acquisition rates ideal for analyte identification of complex mixtures.

The "COMPARE" feature, available in the Data Processing Method of ChromaTOF , is a single point calibration curve generated from a "Reference" sample, used to compare the Reference sample against a target sample. In this application note, the COMPARE feature will be used to compare two different samples of beer analyzed by SBSEGCxGC- TOFMS. The objective is to identify variations in twenty targeted compounds between the two samples. The Reference sample is of beer stored cold. The other sample is of the same beer that had been stored at an elevated temperature. For the remainder of this work, the sample from which the reference standard is made will be referred to as the "Reference" and the sample being compared to the reference standard will be called the "Sample".