Dichlorobenzene detection limits

In another study in which male and female Fisher 344 rats were administered a single dose of 900 mg/kg/day 1,4-dichlorobenzene by gavage in com oil and sacrificed at 72 hours, the percentage of the dose found in tissues and excreta from males was tissues (all organs pooled), 0.05% fat, 0.1% blood, 0.04% feces, 3.6% and urine, 41.3%. Thus, more than half (55%) of the dose was probably exhaled 60% was not accounted for. In females recovery of radioactivity was tissue, 0.04% fat, 0.1% blood, 0.03% feces, 2.5% and urine, 37.8%. In the tissues examined, the radioactivity bound to protein was below the detection limit (Klos and Dekant 1994). Charbonneau et al. (1987) reported that 49.8% of... 

The excretion of 1,4-dichlorobenzene and metabolites was examined in male rats administered a single dose of 200 mg/kg 1,4-dichlorobenzene given by gavage in com oil and monitored up to 120 hours after dosing (Kimura et al. 1979). Within 12 hours after dosing, 2 sulfur-containing metabolites, 2,5-dichloro-phenyl methyl sulfoxide, and 2,5-dichlorophenyl methyl sulfone (M2), were found in the blood, urine, fat, liver, and kidneys. These metabolites remained in the blood after most of the 1,4-dichlorobenzene had fallen below the detection limits of the assay. The maximum concentration of 2,5-dichlorophenyl methyl sulfoxide in blood was reached 15 hours after dosing and declined rapidly thereafter. For... 

The purpose of this chapter is to describe the analytical methods that are available for detecting, and/or measuring, and/or monitoring 1,4-dichlorobenzene, its metabolites, and other biomarkers of exposure and effect to 1,4-dichlorobenzene. The intent is not to provide an exhaustive list of analytical methods. Rather, the intention is to identify well established methods that are used as the standard methods of analysis. Many of the analytical methods used for environmental samples are the methods approved by federal agencies and organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other methods presented in this chapter are those that are approved by groups such as the Association of Official Analytical Chemists (AOAC) and the American Public Health Association (APHA). Additionally, analytical methods are included that modify previously used methods to obtain lower detection limits, and/or to improve accuracy and precision. 

Although a variety of methods are available for determination of 1,4-dichlorobenzene in blood, few are well characterized and validated. A method has been developed which utilizes headspace purge followed by thermal desorption of the trapped, purged analytes. 1,4-Dichlorobenzene is then determined by capillary GC/MS (Michael et al. 1980 Pellizzari et al. 1985). Recovery is very good (>85%) and detection limits are in the low-ppb range for model compounds (Michael et al. 1980 Pellizzari et al. 1985). Performance data are not available for 1,4-dichlorobenzene. A sensitive and reliable method for identification and quantitation of 1,4-dichlorobenzene in samples of whole blood has been developed by Ashley and coworkers at the Centers for Disease Control and Prevention (CDC) (Ashley et al. 1992). 

Methods are available for monitoring 1,4-dichlorobenzene in urine and tissues, particularly adipose tissue and mother s milk. Solvent extraction, silica gel column clean-up, and GC/ECD or GC/PID analysis has been used for urine (Langhorst and Nestrick 1979), mother s milk (Jan 1983), and adipose tissue (Jan 1983). Recovery is good (>80% recovery) and detection limits are in the low-ppb range (Jan 1983 Langhorst and Nestrick 1979). Headspace purge, followed by capillarity GC/MS analysis has been utilized for urine (Michael et al. 1980), mother s milk (Erickson et al. 1980), and tissue (Pellizzari et al. 1985). Recovery, where reported, is adequate (>60%) (Erickson et al. 1980), and detection limits are in the low-ppb range (Erickson et al. 1980). 

The detection limit for dichloropropane is only 60pg L, and the dichlorobenzenes cannot be detected below 500pg L. This analysis is not, therefore, suitable for detecting trace levels of some of the dichlorinated hydrocarbons in water. 

The results of this study show that chlorobenzenes can be expected to occur at trace levels in UK sewage sludge. Concentrations will vary widely, with dichlorobenzenes likely to occur in the range up to 50 ppm, trichlorobenzenes up to 3 ppm, tetrachlorobenzenes up to 0.3 ppm and hexachlorobenzene up to 0.5 ppm. Pentachlorobenzene never occurred at concentrations above the detection limit (0.01 ppm) in the samples examined and therefore is unlikely to be a significant contaminant in sewage sludge. 

After an extensive comparison of different cationic dyes and extraction solvents for the FI liquid-liquid extraction spectrophotometric determination of anionic surfactants, Motomitzu et al.[27] recommended the use of Methylene Blue and 1,2-dichlorobenzene. A detection limit of 5 pg 1 was achieved with a sampling frequency of 20 h , and a precision of 0.9% r.s.d. in the analysis of river waters (for details cf. Sec. 8.8.2). 

NOTE N/A, not applicable N/R, not reported and N/D, not detected. Explosives detection limits at Porton Down 50 mg/L for HMX, RDX, TNT, tetryl 65 mg/L for nitrocellulose 30 mg/L for nitroglycerin. Semivolatile organics (SVOCs) analyzed at Poiton Down 1,4-dichlorobenzene, 2,4- and 2,6-dinitrotoluene, hexachlorobutadiene, nitrobenzene, o-cresol, pentachlorophenol, pyridine, 1,2,4-trichlorobenzene, 2,4,5- and 2,4,6-trichlorophenol. Detection limit on all SVOCs except pyridine was 0.6 mg/L that for pyridine was 0.7 mg/L. Volatile organics (VOCs) analyzed at Potion Down benzene, carbon tetrachloride, chlorobenzene, chloroform, 1,4-dichlorobenzene, 1,2-dichloroethane, 1,1-dichloroethylene, 1,1,1,2- and 1,1,2,2-tetrachloroethane, trichloroethylene, 2-butanone (methyl ethyl ketone (MEK)), and vinyl chloride. Detection limit was 1 mg/L on all VOCs. 

Crisp et al. [212] has described a method for the determination of non-ionic detergent concentrations between 0.05 and 2 mg/1 in fresh, estuarine, and seawater based on solvent extraction of the detergent-potassium tetrathiocyana-tozincate (II) complex followed by determination of extracted zinc by atomic AAS. A method is described for the determination of non-ionic surfactants in the concentration range 0.05-2 mg/1. Surfactant molecules are extracted into 1,2-dichlorobenzene as a neutral adduct with potassium tetrathiocyanatozin-cate (II), and the determination is completed by AAS. With a 150 ml water sample the limit of detection is 0.03 mg/1 (as Triton X-100). The method is relatively free from interference by anionic surfactants the presence of up to 5 mg/1 of anionic surfactant introduces an error of no more than 0.07 mg/1 (as Triton X-100) in the apparent non-ionic surfactant concentration. The performance of this method in the presence of anionic surfactants is of special importance, since most natural samples which contain non-ionic surfactants also contain anionic surfactants. Soaps, such as sodium stearate, do not interfere with the recovery of Triton X-100 (1 mg/1) when present at the same concentration (i.e., mg/1). Cationic surfactants, however, form extractable nonassociation compounds with the tetrathiocyanatozincate ion and interfere with the method. 

The solvents used in analytical TREF are limited to chlorinated solvents, mainly ort/io-dichlorobenzene and 1,2,4 tri-chlorobenzene (perchloroethylene and a-chloronaphtalene have also been used), which can dissolve the polyolefins at high temperature and are transparent enough in the IR region of measurement. These solvents are the same as used in GPC/SEC analysis of polyolefins and are also appropriate for detection by refractive index, although this detector has not... 

With this method, data acquisition in the full-scan mode allows mass spectra to be acquired for subsequent identification through library searching even at the required limit of detection of 0.1 ppbv. Figures 4.5 and 4.6 show examples of comparability of the spectra and the identification of dichlorobenzene at 20.0 and 0.1 ppbv. With the procedure described, both the compounds required according to TO-14 and other unexpected components in the critical concentration range can be identified. 

---