Collecting urine samples from young children using cotton gauze for pesticide studies

Abstract

To estimate pesticide exposure, urine samples are often needed to analyze pesticide metabolites. However, this is difficult for children wearing diapers because simple and feasible techniques suitable for field collection are not available. The objectives of this study were to test the validity of using cotton gauze pad as a medium for collecting urine samples from young children and to examine the stability of the recoveries for creatinine and pesticide metabolites over 24 h. Urine spiked with a pesticide and four metabolites, 2,4 -dichlorophenoxyacetic acid ( which is mainly eliminated from urine unchanged ) , 3 -phenoxybenzoic acid ( metabolite for synthetic pyrethroids ) , atrazine mercapturate ( metabolite for atrazine ) , malathion dicarboxylic acid ( metabolite for malathion ) , and 2 -isopropyl -4 -methyl -6 -hydroxypyrimidine ( metabolite for diazinon ) was added to the gauze pads and kept in jars at 378C in a water bath. Urine was expressed from the gauze pads immediately and after 1, 2, 4, 8, and 24 h, then analyzed. The recoveries, calculated as the percentage of concentration in expressed urine divided by that of the control urine sample, were within a range of 70 ± 130%. The metabolite and creatinine concentrations did not change with time in either expressed urine samples or controls. The results suggest that cotton gauze pad is a promising candidate for collecting urine samples from young children wearing diapers for studies in which these five urinary pesticide metabolites are to be analyzed. Journal of Exposure Analysis and Environmental Epidemiology ( 2000 ) 10, 703 ± 709.

Nondietary ingestion of pesticides by children in an agricultural community on the US/Mexico border: Preliminary results

“…Because of difficulties in extracting the urine from the gel formed in commercially available disposable diapers, these are generally not considered useful for urine collection. Some investigators have utilized cotton gauze for this purpose (Hu et al, 2000 ). A similar methodology was employed; however, in place of cotton gauze, cotton terry cloth diaper inserts ( Organic Diaper Doublers; Ecobaby Organics, El Cajon, CA ) were employed.…”

Urine-sampling methods for environmental chemicals in infants and young children

“…Furthermore, the percentage recoveries of creatinine and metabolites have been shown to be acceptable, ranging from 70-130% in the laboratory, although recoveries depend on the analyte of interest (Hu et al, 2000). Additional advantages of a cotton ball or gauze insert include cost effectiveness of supplies and a substantial decrease in the time spent by a health care professional to apply the material, as compared with the use of a urine collection bag (Burke, 1995).…”

“…The cotton insert may be frozen and shipped to the laboratory, where it is centrifuged to extract urine, although the volume recovered is often small (Calafat et al, 2004). Urine may also be extracted from the cotton pad through use of a disposable syringe on-site (Hu et al, 2000;Shalat et al, 2003;Zohouri et al, 2006) by placing the gauze into an empty syringe, replacing the plunger and squeezing urine into vials (Weuve et al, 2006). Alternatively, the urine can be aspirated from the pad using a syringe (Shalat et al, 2003;Dorey and Zimmermann, 2008).…”

“…The pad should be checked frequently (every 10 min) until the pad is wet with urine but not soiled by feces (Dorey and Zimmermann, 2008). Use of a cotton insert is relatively simple as the urine may be expressed on-site and the pad may be removed fairly easily from the diaper for analysis (Hu et al, 2000). In addition, cotton will maintain the stability of the urine sample for at least 24 h at 371C (Hu et al, 2000), and will not interfere/react with urinary creatinine concentration nor the concentrations of most chemicals used for clinical diagnoses (Roberts and Lucas, 1985;Hu et al, 2000).…”

“…Dorey and Zimmermann (2008) were able to extract approximately 2 ml of urine from cotton pads. To some extent the insufficient sample obtained can be corrected with the addition of water to the cotton pad and successive extractants, with back-calculations of creatinine concentration used to ensure unbiased normalization (Hu et al, 2000).…”