German coast of the North Sea aboard the 60-m research vessel Heinckk in search ho phosphine.

"Even if we do not know yet how phosphine is formed biologically," Gass-mann explains, "we are able to account for the final product phosphine without any doubts in places where methanogenic con­ditions prevail."

Gassmann is one of only two marine chemists at Biological Institute Helgoland, the oldest marine research institute in Ger­many. Founded in 1892 on the rocky island of Helgoland, it was a federal institute until last year. Since January it has been orga­nized under the umbrella of the Founda­tion Alfred-Wegener-Institute for Polar and Marine Research in Bremerhaven, a mem­ber of the Helmholz Association of German Research Centers. The change in organiza­tion means that Gassmann and his col­leagues in Hamburg leave for Bremer­haven this month. An easy task thanks to his mobile lab equipment.

The Biological Institute Helgoland runs two island stations—the Marine Station on Helgoland and the Waddensea Station on the island of Sylt, which is located at the seabound border of the mudflats off the northern coast of Germany.

As a marine chemist Gassmann originally was interested in phosphate cycles of marine

ecosystems. Ten years ago phosphine caught his attention. "Phosphine has two faces," Gassmann explains. "Technically fabricated, it has broad application in corn storage as an insecticide and fungicide as well as in chip fabrication as a doping gas to incorporate foreign atoms into semiconduc­tor materials. On the other hand, it is a highly dangerous substance." Concentra­tions as low as 20 ng/kg are considered toxic. Moreover, it is carcinogenic and leads to leukemia. Even subtoxic concentrations can accumulate in the body.

In 1993, Gassmann began collaborating with Dieter Glindemann of the University of Leipzig, who succeeded in modifying Gas-smann's apparatus so that phosphine could be analyzed in the air above the sea surface at the attogram level. This was imporrant because of the compound's high toxicity.

Aboard the Heincke aii ramples of 50-500 mL are pressed through an adsorption cartridge, removing hydrogen sulfide, carbon dioxide, and water. After passing through the cartridge the eluent is cryo-focused for adsorption of phosphine and high-molecular-weight hydrocarbons. The trapped sample is then focused again by thermodesorption into another trapping device cooled to liquid nitrogen tempera­tures. Sudden thermodesorption is used to push phosphine and very volatile hydrocar­

bons into a capillary where the phosphine is separated from the light hydrocarbons. Quantitative analysis is performed with a thermionic detector.

During their cruises off the German coast, Gassmann and Glindemann found daily mean phosphine concentrations of 50 pg/m2 and peaks of 800 pg/m2 at night. In summer, when air temperatures reach 20 °C, and at low tide, when vast areas of the Waddensea are laying dry, 15 ug of phosphine are gassing out from one square meter of the mud flats during this tide cy­cle—750 times more than the toxic level.

"Since the middle of the last century, sci­entists [have] pointed out that the occur­rence of cancer and cancer lethality is in cor­relation with certain geophysical factors," Gassmann remarks. "In the vicinity of humid grounds and in areas often flooded by rivers, the risk for cancer is increased."

What the findings of Gassmann and Glindemann may mean to people living at the coasts has yet to be investigated. In Germany the findings of the marine chem­ists have added a new view to environmen­tal discussions. Nuclear power plants have been blamed for increased occurrences of childhood leukemia, but most of the Ger­man plants are located in humid areas near river banks.

Hanns-J. Neubert

NEWS FROM ANALYTICA ’98

Celia Henry and Veronika Meyer report from Munich, Germany

"Quick-and-dirty" pesticide analysis Udo Brinkman of the Free University of Am­sterdam (The Netherlands) now uses very short HPLC columns for pesticide analysis of river water. Until recently, sample prepara­tion involved solid-phase extraction directly coupled to a 25-cm column. However, 95% oo more of the samples from the Rhine River and its tributaries are pesticide-free. "For these samples, it is not necessary to use such a sophisticated analytical system, so we tried [to see] if we could do it in a simpler way," Brinkman explained.

The new approach works. A 15-mL wa­ter sample is pumped through a 2-cm reversed-phase column that can separate 16 pesticides with a 13-min gradient. Detec­tion is done by MS/MS. Although the col­umn lasts for only 30-40 injections before it must be replaced, this approach is very attractive, says Brinkman.

Now even 1-cm columns have been suc­cessfully used. The sample volume in this case is 4 mL, and a run takes only 4 min plus 1 min for regeneration. Linearity and limit of detection (10-100 ng/L) are compa­rable to more conventional trace analytical methods for pesticides in water.

On-site analysis of contaminated soils Bringing the analytical equipment to the field can be more advantageous than bring­ing the samples to the laboratory. Gerhard Zwickof Ansyco (Germany) described how it is possible to obtain high-quality data of contaminated soils in the field.

He used a battery-powered, hand-held photoionization detector (PID) for the non­selective determination of volatile organic compounds; an isothermal gas chromato-graph with a 30-m wide-bore column for the selective analysis of the same com­

pounds; and a portable IR spectrometer for the determination of nonvolatile hydrocar­bons after their extraction from the soil samples with R113 (a halogenated solvent allowed for analytical purposes by the Mon­treal Protocol). PID and GC analyses corre­lated well at the site of investigation, but the PID is fast and much simpler to handle. The IR analyses did not correlate with those of the other techniques, which is not surprising because the techniques are usu­ally used for other classes of compounds.

On-site analysis has the advantage that the whole analytical process from sampling to data evaluation and interpretation is done by the same person The sampling strategy (both on the surface and at a depth down to several meters) can be adapted immediately as indicated by the results The instruments are easy to handle and rugged; Zwick and his colleagues regret that the on-site at> proach is not yet widelv accented by the analytical communitv

Analytical Chemistry News & Features, July 1, 1998 445 A