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A parallel nanoliter microfluidic analysis system based on capillary action, centrifugal force, and hydrophobic barriers is described. The precision of 112 parallel volume definition operations is determined to 0.75% CV at 200 nL using the individual sample introduction structure. For 20 nL, the actual measurement error is the dominating factor, with a combined error of 1.9% CV. Individual dispensing as well as dispensing through a common distribution channel is described. The volume definition precision for the common distribution channel is 1.6% CV for 200 nL. Unlike the dominating forces in microlitersized channel systems, we describe hysteresis effects as exerting a major influence, which needs to be considered in order to control the operation and design of discrete nanoliter fluidics. Hydrophobic patches at the corners of the rectangular channel control corner-enhanced wicking. Excellent flow control of 1 and 2 nL/s is achieved using a predefined spin program.In comparison with conventional analysis systems, µ-TAS (micro total analysis system) have the potential to achieve faster analysis times, improve automation, consume less reagents, gain more information from less sample, and significantly increase throughput by running parallel analyses. 1 The development of µ-TAS-based parallel analysis systems has shown to be demanding. In 2001, Cheng et al. showed six parallel analyses 2 using electroosmotic (EO) flow; however, despite more than a decade of research on electroosmotic (EO) pumping, parallel separation systems have been challenging to develop. Some of the challenges using EO-pumping-based systems have been described earlier. 3,4 With suppressed EO flow, conventional multicapillary DNA electrophoresis was transferred to a chip performing parallel separations on 384 samples. 5 At present, most of the µ-TAS systems use a continuously pumped approach, i.e., liquid is pumped from an inlet reservoir to an outlet reservoir, and in most cases the volumes of sample and reagents needed to interface with the chip are several orders of magnitude higher than the volumes used in the analysis. This is also true of the parallel multilayer elastomeric system proposed by Unger et al.,4 where an additional issue of sample and reagent compatibility with the elastomeric material has to be resolved. Moreover, using a continuous flow system requires reliable liquid connections to the chip; a chip with 100 or more channels requires at least 200 electrodes for the simplest EO case, 6 or hundreds of low dead volume pressure connections for pressure-driven systems. It is difficult to eliminate error in such a system, particularly if a disposable chip format is used. Centrifugal analyzers enable the development of parallel analysis systems without external connections. Miniaturized centrifugal analyzers for microliter volumes were reported in 1973; these used a plastic disc with the same diameter (12 cm) as used in today's compact discs (CD). 7 In another microliter-range centrifugal system, a microfabricated burst valve was i...

Textiles play an important role in our daily life, and textile production is one of the oldest industries. In the manufacturing chain from natural and/or synthetic fibers to the final clothing products, the use of many different chemicals is ubiquitous. A lot of research has focused on chemicals in textile wastewater, but the knowledge of the actual content of harmful chemicals in clothes sold on the retail market is limited. In this paper, we have focused on eight benzothiazole and benzotriazole derivatives, compounds rated as high production volume chemicals. Twenty-six clothing samples of various textile materials and colors manufactured in 14 different countries were analyzed in textile clothing using liquid chromatography tandem mass spectrometry. Among the investigated textile products, 11 clothes were for babies, toddlers, and children. Eight of the 11 compounds included in the investigation were detected in the textiles. Benzothiazole was present in 23 of 26 investigated garments in concentrations ranging from 0.45 to 51 μg/g textile. The garment with the highest concentration of benzothiazole contained a total amount of 8.3 mg of the chemical. The third highest concentration of benzothiazole (22 μg/g) was detected in a baby body made from "organic cotton" equipped with the "Nordic Ecolabel" ("Svanenmärkt"). It was also found that concentrations of benzothiazoles in general were much higher than those for benzotriazoles. This study implicates that clothing textiles can be a possible route for human exposure to harmful chemicals by skin contact, as well as being a potential source of environmental pollutants via laundering and release to household wastewater.

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