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A method to distinguish the four most common biologically relevant underivatized hexoses, d-glucose, d-galactose, d-mannose, and d-fructose, using only mass spectrometry with no prior separation/derivatization step has been developed. Electrospray of a solution containing hexose and a lithium salt generates [Hexose+Li]+. The lithium-cationized hexoses adduct water in a quadrupole ion trap. The rate of this water adduction reaction can be used to distinguish the four hexoses. Additionally, for each hexose, multiple lithiation sites are possible, allowing for multiple structures of [Hexose+Li]+. Electrospray produces at least one structure that reacts with water and at least one that does not. The ratio of unreactive lithium-cationized hexose to total lithium-cationized hexose is unique for the four hexoses studied, providing a second method for distinguishing the isomers. Use of the water adduction reaction rate or the unreactive ratio provides two separate methods for confidently (p ≤ 0.02) distinguishing...

A method has been developed that is capable of distinguishing an exhaustive list of underivatized D-pentoses with only a mass spectrometer. Electrospray ionization (ESI) of a solution containing a pentose and a lithium salt yields [Pentose + Li]+. These lithiated pentoses adduct water in a quadrupole ion trap. The reaction rate of water adduction is unique for several of the pentose isomers. Additionally, there are multiple potential gas-phase lithiation sites to form [Pentose + Li]+. A mixture of ions with at least one reactive (water adducting) and at least one unreactive (non-adducting) lithiation site is formed for each pentose. The water adduction reaction rate along with the unreactive fraction of lithiated pentose can be used to completely discriminate all D-pentoses.

Background Much of the marked increase in incidence of non-Hodgkin lymphoma (NHL) over the past few decades remains unexplained. Organochlorines, including organochlorine pesticides (OCPs), have been implicated as possible contributors to the increase, but the evidence is inconsistent. Objectives To investigate the relation between pre-diagnostic levels of OCPs and risk of NHL in a case-control study nested within the population-based Janus Serum Bank Cohort in Norway. Methods Prediagnostic concentrations of 11 OCPs or OCP metabolites were measured in baseline blood samples collected between 1972 and 1978 from 190 cases and 190 controls matched on sex, county, age at blood draw, and date of blood draw. We conducted conditional logistic regression to estimate adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for each quartile of lipid-corrected OCP/metabolite relative to the lowest quartile. Results We observed non-significantly elevated ORs across quartiles of β-hexachlorocyclohexane compared to the lowest quartile (OR range: 1.40–1.82) although with no apparent monotonic exposure-response relationship. We also found an inverse association between risk of NHL and o,p'-DDT (OR for Q4 vs. Q1 = 0.44, 95% CI: 0.19, 1.01; p-trend = 0.05). In analyses stratified by age at blood collection and duration of follow-up, several other analytes, primarily chlordane-related compounds, showed inverse associations among younger participants or those with longer follow-up time between blood draw and NHL diagnosis. Conclusions We found only limited evidence of positive association between selected OCPs and development of NHL.

A method was developed to distinguish both the linkage position and the anomericity of all reducing and two nonreducing glucopyransosyl–glucose disaccharides using only electrospray ionization–mass spectrometry/mass spectrometry (ESI–MS/MS). Carbohydrates are well-known to form complexes with metal cations during electrospray ionization. Addition of a lithium salt to a solution containing a disaccharide, M, results in [M + Li]+ after ESI. Collision-induced dissociation of these ions creates product ions at m/z 187 and m/z 169 from cleavage of the glycosidic bond and are present for all disaccharides studied. Both of these product ions were found to adduct water after their formation in a quadrupole ion trap. The kinetics of this water adduction can be measured by isolating either of the product ions and waiting a short time (