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ANALYTICAL CHEMISTRY, VOL 59 NO 6 MADCH 15, 1987
ductiori of the peak height when 4 nig L ' ut Triton 1% added and 2 X 10.' M catechol is used for the ("?V tnwc~iretrient (12).
Experiments showed that seawater stored in polyethylene bottles (250 mL volume) contained surface-active organic material that interfered with the CSV arialysiq of uranium when using catechol: pronounced organic peaks (presumably phthalate esters) were produced when the differential pulse mode was used (recommended for greatest sensitivity for the catechol method (12)) at -0.4 and -0.6 V This interference was not observed in the presence of oxine and when the linear scanning mode was employed. The possible interfering effect of natural orgaiii(, chelators was tested by adding EDTA to the solution i n the presence of 2 X 10-5M oxine. No reduction in the I J W ) peak height was caused by 3 x M EDTA, but the peak height diminished by 25% when I O I\/I EPTA was added 'Ihe bent3cial effect of masking lead and c~adrriiiima t R lower level of EDTA (loe4M) has been mentioned earlier. The use of oxine for the csv analysis ( J f uratiiutn in water was compared with that of catechol ( 2 2 ) iii seawater before and after IW irradiation at the origirinl qaniple pH. The following concentrations were obtained when using oxine (catechol): sample from Menai Straits, after li V irradiation, 1.9 nM (2.2 nM); irradiated channel water, 1.9 nM (2.0 nM); untreated Menai Straits water, 14.1 IIM r t 4 0 nM). The agreement between the procedures was very good. Siinilar comparison in freshwater conditions was not possible because of the poor sensitivity with catechol at low snliriities
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ACKNOWLEDGMENT The authors gratefully acknowledge the typing of the manuscript by Sue Perry and the preparation of the drawings by J. Murphy. Registry No. I, 148-24-3; HzO, 7732-18-5; U, 7440-61-1. LITERATURE CITED Florence, T. M.; Farrar, Y. Anal. Chem. 1963 35, 1613-1616. Pakalns, P. Anal. Chim. Acta 1980, 120,289-296. Chao, H. E.; Suzuki, N. Anal. Chim. Acta 1981, 725,139-147. Oguma, K.; Maruyarna, T.; Kuroda, R. Anal. Chim. Acta 1975, 7 4 , 339-345. Wilson, J. D.; Webster, R. K.; Miiner, G. W. C.; Barnett, G. A,; Smales, A. A. Anal. Chim. Acta 1960, 23,505-514. Holzbecher, J.; Ryan, D. E. Anal. Chim. Acta 1980, 779,405-408. Langmuir, D. Geochim. Cosmochim. Acta 1978, 42 547-569. Milner, G. W. C.; Wilson, J. D.; Barnett, G.A , ; Smales, A. A. J , Electroanal. Chem. 1961, 2 , 25-38. Lubert, K.-H.; Schnurrbusch, M.; Thomas, A. Anal. Chim. Acta 1982, 744,123-136. Izutsu, K.; Nakamura, T.; Ando, T. Anal. Chim. Acta 1983, 752, 205-288. Lam, N. K.; Kalvoda, R.; Kopanica, M. Anal. Chim. Acta 1983, 754, 79-86. van den Berg, C. M. G.; Huang, 2. Q. Anal. Chim. Acta 1984, 164, 209-222. van den Berg, C. M. G.; Huang, 2. Q. Anal. Chem. 1984, 5 6 , 2383-2386. Sipos, L.; Jeftic, L. J.; Branica, M. J , Eiectroanai. Chem. Interfacial Electrochem. 1971, 32 35-47. Smith, R. M.; Martell, A. E. Critical Stability Constants; Plenum: New York, 1975; Vol. 2, p 223. van den Berg, C. M. G. Anal. Chem. 1985, 57, 1532-1536.
RECEIVED for review June 16, 1986. Resubmitted October 27, 1986. Accepted December 2 , 1986.
CORRECTION Nonelectric Gas Chromatograph with Direct Opticalto-Pneumatic and Pneumatic-to-Optical Conversion for Transmission and Control Raymond Aiiiiirio, Charles Caffert, and E. L. Lewis (Anal. Chem. 1986, 58, 2516-2523). On p 2521 under Results, the first paragraph should read: Control System. It was found that a minimum of 0.70 mW of power was required a t the exit end of the fiber for the ciirrent version of the LPA switch to operate reliably. At the commonly ohserved 3 dB/km power loss in multimode fiber transmission, the present fiber output will be 0.5 mW at 1 km. 'I'hus, for transmission distances of greater than 0.5 km, a higher powerrd 191) must be substituted for the one described liereiri.
