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Inductively coupled plasma/optical emission spectrometry (ICP/OES) is a powerful tool for the determination of metals in a variety of different sample matrices. With this technique, liquid samples are injected into a radiofrequency (RF)‐induced argon plasma using one of a variety of nebulizers or sample introduction techniques. The sample mist reaching the plasma is quickly dried, vaporized, and energized through collisional excitation at high temperature. The atomic emission emanating from the plasma is viewed in either a radial or axial configuration, collected with a lens or mirror, and imaged onto the entrance slit of a wavelength selection device. Single element measurements can be performed cost‐effectively with a simple monochromator/photomultiplier tube (PMT) combination, and simultaneous multielement determinations are performed for up to 70 elements with the combination of a polychromator and an array detector. The analytical performance of such systems is competitive with most other inorganic analysis techniques, especially with regards to sample throughput and sensitivity.

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Standard dilution analysis (SDA) is a novel calibration method that may be applied to most instrumental techniques that will accept liquid samples and are capable of monitoring two wavelengths simultaneously. It combines the traditional methods of standard additions and internal standards. Therefore, it simultaneously corrects for matrix effects and for fluctuations due to changes in sample size, orientation, or instrumental parameters. SDA requires only 200 s per sample with inductively coupled plasma optical emission spectrometry (ICP OES). Neither the preparation of a series of standard solutions nor the construction of a universal calibration graph is required. The analysis is performed by combining two solutions in a single container: the first containing 50% sample and 50% standard mixture; the second containing 50% sample and 50% solvent. Data are collected in real time as the first solution is diluted by the second one. The results are used to prepare a plot of the analyte-to-internal standard signal ratio on the y-axis versus the inverse of the internal standard concentration on the x-axis. The analyte concentration in the sample is determined from the ratio of the slope and intercept of that plot. The method has been applied to the determination of FD&C dye Blue No. 1 in mouthwash by molecular absorption spectrometry and to the determination of eight metals in mouthwash, wine, cola, nitric acid, and water by ICP OES. Both the accuracy and precision for SDA are better than those observed for the external calibration, standard additions, and internal standard methods using ICP OES.

The fourteen Lanthanides are determined by tungsten coil atomic emission spectrometry. Twentyfive microlitre sample aliquots are placed directly on the coil. A simple constant current power source carefully dries the sample prior to analysis. During this dry step, the voltage is monitored to prevent over heating. This allows for shorter atomization programs, while improving sensitivity and coil lifetime. During the 5 s high temperature atomization step, the emission signals for as many as seven Lanthanides are determined simultaneously in the same 55 nm spectral window. The analytical figures of merit for all 14 natural Lanthanides are reported and compared with nitrous oxide flame atomic emission spectrometry. Tungsten coil atomic emission concentration detection limits are in the range 0.8 (Yb) to 600 (Pr) mg l À1 , and are lower than those for the flame in most cases. The absolute detection limits are near or below the ng level: significantly lower than the flame detection limits due to the smaller sample volume required. A three-fold improvement in detection limit may be realized by combining the signals for multiple emission lines for a single element. The method is applied to the determination of seven Lanthanides in a soil sample acquired from the National Institute of Standards and Technology. After a simple acid extraction, the measured values agree with the reported values with 95% confidence in all cases but one, Yb. Finally, a conditioning program for new tungsten coils enhances reproducibility and maximizes the emission signal.

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Carbon nanotubes are unique materials that absorb infrared (IR) radiation, especially between 700 and 1100 nm, where body tissues are most transparent. Absorbed IR promotes molecular oscillation leading to efficient heating of the surrounding environment. A method to enhance drug localization for peritoneal malignancies is perfusion of warm (40-42 degrees C) chemotherapeutic agents in the abdomen. However, all tissues in the peritoneal cavity are subjected to enhanced drug delivery due to increased cell membrane permeability at hyperthermic temperatures. Here we show that rapid heating (within ten seconds) of colorectal cancer cells to 42 degrees C, using infrared stimulation of nanotubes as a heat source, in the presence of the drugs oxaliplatin or mitomycin C, is as effective as two hours of radiative heating at 42 degrees C for the treatment of peritoneal dissemination of colorectal cancer. We demonstrate increased cell membrane permeability due to hyperthermia from multiwalled carbon nanotubes in close proximity to cell membranes and that the amount of drug internalized by colorectal cancer cells heated quickly using carbon nanotubes equals levels achieved during routine application of hyperthermia at 42 degrees C. This approach has the potential to be used as a rapid bench to bedside clinical therapeutic agent with significant impact for localizing chemotherapy agents during the surgical management of peritoneal dissemination of colorectal cancer.

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