Storage stability studies for tributyltin determination in human urine samples using headspace solid‐phase microextraction and gas chromatography mass spectrometry

Abstract

A headspace solid-phase micro-extraction (HS-SPME) method was employed in order to study the effect of storage conditions of human urine samples spiked with tributyltin (TBT) using gas chromatography and mass spectrometry. To render the analyte more volatile, the derivatization (ethylation) was made in situ by sodium tetraethylborate (NaBEt(4) ), which was added directly to dilute unpreserved urine samples and in buffers of similar acidity. The stability of TBT in human urine matrix was compared with the stability of TBT in buffer solutions of similar pH value. Critical parameters of storage conditions such as temperature and time, which affect the stability of TBT in this kind of matrix, were examined extensively. The tests showed that the stability of TBT remains practically satisfactory for a maximum of 2 days of storage either at +4 or 20°C. Greater variations were observed in the concentration of TBT in human urine samples at +4°C and lower ones at -20°C over a month's storage. The freeze-thaw cycles have negative effect on the stability and should be kept to a minimum. The results from spiked urine samples are also discussed in comparison to those acquired from buffer solutions of equal TBT concentration.

Atomic spectrometry update: Review of advances in the analysis of clinical and biological materials, foods and beverages

“…Zachariadis et al 21 investigated the stability of TBT in human urine and found that storage at 4 or À20 C was possible for no more than 2 days. Thereaer, greater variation was seen in those maintained at 4 C compared to À20 C. Losses were also noted following freeze-thaw cycles.…”

“…Sunday et al 15 presented a detailed review of the chemical speciation of organotin compounds in environmental and biological matrices. Zachariadis et al 21 investigated the effect of storage conditions on the stability of tributyltin (TBT) species in human urine. Spiked urine and buffer samples were stored at 4 C and À20 C for up to one month.…”

Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages

“…Sunday et al 15 presented a detailed review of the chemical speciation of organotin compounds in environmental and biological matrices. Zachariadis et al 21 investigated the effect of storage conditions on the stability of tributyltin (TBT) species in human urine. Spiked urine and buffer samples were stored at 4 C and À20 C for up to one month.…”