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A novel microsystem device in poly(dimethylsiloxane) (PDMS) for MS detection is presented. The microchip integrates sample injection, capillary electrophoretic separation, and electrospray emitter in a single substrate, and all modules are fabricated in the PDMS bulk material. The injection and separation flow is driven electrokinetically and the total amount of external equipment needed consists of a three-channel high-voltage power supply. The instant switching between sample injection and separation is performed through a series of low-cost relays, limiting the separation field strength to a maximum of 270 V/cm. We show that this set-up is sufficient to accomplish electrospray MS analysis and, to a moderate extent, microchip separation of standard peptides. A new method of instant in-channel oxidation makes it possible to overcome the problem of irreversibly bonded PDMS channels that have recovered their hydrophobic properties over time. The fast method turns the channel surfaces hydrophilic and less prone to nonspecific analyte adsorption, yielding better separation efficiencies and higher apparent peptide mobilities.

In this work, we studied the behavior of electrophoretic columns, having an inner diameter (ID) of 2-10 microm, filled with a cross-linked polyacrylamide gel matrix. The usefulness of these columns for DNA sequencing is discussed. Evaluation of column performance included tests of gel stability and migration time reproducibility. Confocal laser-induced fluorescence (LIF)-detection was employed utilizing a 488 nm argon ion laser for separations of C- and T-terminated DNA Sanger fragments. Reducing the inner diameter of the column from 50 microm to 10 microm resulted in an approximately eightfold increase in lifetime, under conditions in which the columns were subjected to a field strength of 1000 V/cm. The 10 microm ID columns were utilized for separation of Sanger fragments, and adequate detection sensitivity was obtained by stacking of the fragments from a deionized sample solution. A linear algorithm for retention data synchronization between individual electropherograms was employed to provide a route towards a reliable automated base calling protocol.

The performance of poly(N-acryloylaminopropanol) (poly AAP) gel columns, proved to be stable during electrophoresis at elevated temperature, was investigated. The column manufacturing procedure included the preparation of a coating of the inner wall of the fused silica capillary column with linear poly(AAP). Then, a mixture of the AAP monomer, the cross-linker dihydroxyethylenebisacrylamide (DHEBA) and linear poly(AAP) was introduced into the column and in situ polymerized (for preparation of linear gel columns, the addition of DHEBA was omitted). The poly(AAP) columns were first evaluated by electrophoresis of oligonucleotides at room temperature and at 50 degrees C, utilizing 260 nm UV-absorbance detection. In a further evaluation of column performance, samples of T-terminated DNA Sanger fragments from the bacteria Moraxella were separated at 200 V/cm electrical field strength, utilizing a 488 nm argon ion laser and a confocal optical setup for laser-induced fluorescence (LIF) detection. A temperature increase from 25 degrees C to 50 degrees C effectively released a compression of DNA bands. However, for cross-linked poly(AAP) gel columns, the elevated temperature resulted in a considerable reduction of the DNA sequence reading length. When a linear poly(AAP) column was utilized, no detrimental effect of elevated temperature on the separation could be observed.

Previous analyses of 52 peregrine falcon (Falco peregrinus) eggs collected from two wild and one captive population in Sweden 1987 through 1999 were complemented by including additional polybrominated diphenyl ether (PBDE) congeners (BDE-35, -183, -184, -185, -196, -197, -203, and -207). In addition, 31 eggs not previously analyzed for hexabromocyclododecane (HBCD) and BDE-209 were analyzed for these. Geometric mean concentrations of BPBDEs, HBCD, and the hexabrominated biphenyl (BB-153) were 3,100, 140, and 81 ng/g of lipid weight for the southern population; 2,500, 110, and 84 ng/g of lipid weight for the northern population; and 47, not detected, and 8 ng/g of lipid weight for the captive population. The BDE congener pattern was dominated by BDE-153, -99, and -100. The results were used to investigate whether a difference in PBDE congener pattern could be distinguished between the two wild populations of peregrine falcons due to different diets, as the southern population preys mainly on birds belonging to the terrestrial food chain while the northern population preys more on aquatic birds. A multivariate t-test showed a subtle but significant (p < 0.001) difference in PBDE congener pattern between the two populations. However, our hypothesis that higher-brominated congeners of PBDEs would be present to a greater extent in the terrestrial food chain was not supported by principal component analysis. The average brood size for individual females from the southern population decreased with increasing concentrations of IPBDE in the eggs (log-linear regression p < 0.01).