Recent evidence suggests that fluoride (F) Febrero (F 9.4±0.9mg/L; As 194±1.3µg/L). The final study sample consisted of 132 children from 6 to 10 years old. After controlling for confounders, an inverse association was observed between F in urine and Performance, Verbal, respectively). Similar results were observed for F in drinking water (β values = -6.7, -11.2, -10.2, respectively) and As in drinking water (β values= -4.30, -6.40, -6.15, respectively). The p-values for all cases were < 0.001. A significant association was observed between p = 0.003). These data suggest that children exposed to either F or As have increased risks of reduced IQ scores.

The low concentrated volatiles of the seed oil of Hibiscus sabdariffa (Malvaceae, Engl. Roselle), eluting ahead of the fatty acids (main constituents of this oil; ca. 90% ) in gas chromatographic measurements, were analyzed by combined GC-MS and GC-FTIR. More than 25 volatiles, mainly unsaturated (one or two double bonds) hydrocarbons, alcohols, and aldehydes predominating from CS to Cn, were identified.The calyx and leaves of Hibiscus sabdariffa are very important for curries, sauces, jellies, and pickles (Mohiuddin and Zaidi, 1975). The high contents of proteins (Al-Wandawi et al., 19841, amino acids (Singh, 1988), and fatty acids (Ahmed and Hudson, 1982;Cornelius et al., 1970; Ahmed et al., 1979;Sarojini et al., 1984) are characteristic for the seed oil of Roselle. Most of these less volatile compounds were analyzed by TLC and GLC with various detection methods. The volatiles of H. sabdariffa oil with low retention index, eluting ahead of the bulk of fatty acids, are unknown until today. The aim of this work was the identification of these low concentrated volatiles (total amount ca. 7%) by the use of efficient gas chromatographic-spectroscopic systems. MATERIALS AND METHODSH. sabdariffa plants (Malvaceae, Engl. Roselle) from Divisa (Herrera, Panama) were dried in the air (27-37 "C; humidity of the atmosphere 80%) for 4 days and the sperm-nucleus separated afterward. The seed oil was extracted by using the Soxhlet method (4 h) after the seeds were partially crushed in a domestic electric grinder and the solvent (n-hexane) was removed under reduced pressure. Total yield of seed oil was 23 5%.The investigations were performed in two steps: First, the genuine seed oil was analyzed by the mentioned gas chromatographic-spectroscopic systems (sample 1). In the second step, the oil was treated with diazomethane for the preparation of the corresponding methyl esters of the free acids (FAMES) and investigated in the same way (sample 2). Injected volume for gas chromatographic measurements was 1.0 pL of a 0.1% solution (dichloromethane).GC-FID. A HRGC Mega Series GC with integrator system (Carlo Erba) was used. The column was a 30-m bonded RSL-200-FSOT (PDDS) fused silica column with 0.32 mm i.d. and 0.17-pm film thickness (Bio-Rad). The carrier gas was hydrogen (35 kPa). The temperature was programmed from 60 to 300 "C with a heating rate of 10 OC/min. The injector temperature was 250 OC, and the detector (FID) temperature was 350 OC. The split ratio was 1:20. Table I. Volatile Constituents of E 88bdarjff8 Seed o i l compound %" IDb 2,2-dimethyl-3-propyloxirane 2-methyl-5-methoxypentan-2-01 5-methyltetrahydro-2-furanmethanol 2-octen-1-01 octanoic acid 2,4-dimethylheptan-l-ol 1,4-nonadiene 2-nonen-1-01 nonanal nonanoic acid camphor linalool decanol 2,4-decadienal 2,4-dimethyloctanol undecane 2,4-undecadienal 2,5-dimethylnonane dodecane dodecanol 2-ethyl-1-decanol lJ3-tetradecadiene 2-(l-methylheptyl)cyclohexanone 7-hexadecene heptadecane 1-heptadecene Concentrations by GC-FID analysis (sample 2). Identification by 1, ma...

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The purpose of the study was the development of new air-sampling and analytical procedures for benzidine, 3,3'-dichlorobenzidine and their salts. Air is drawn through a glass-fiber filter followed by a bed of silica gel to collect these substances as either particles or vapors. The compounds are extracted from the sampler and analyzed by HPLC with sensitivities in the range of 3 micrograms/m3 for 48-L air samples. The methods were evaluated in the laboratory with test aerosol atomospheres and found to be unaffected by temperature or humidity of the sampled environment. Tests of precision, sample stability and separation from interferants indicate that the method should provide reliable results for personal monitoring procedures.