Pulse-lavage washing is an effective method for defatting of morselized allograft bone in the operating theater.

BACKGROUND AND PURPOSE: Incorporation of fresh-frozen allograft bone and safety aspects associated with this procedure can be improved by removing blood and lipids from the bone. We investigated in a quantitative manner how efficient pulse lavage might be for removal of adipose tissue from morselized allograft bone. METHODS: Depending on the study, the washing was performed with an average of 0.8 L or 1.6 L of sterile saline at room temperature. Fat content of the morselized bone samples was determined using hexane elution. The efficiency of pulse lavage alone was compared with that after an additional wash in 12 L of warm water (55 degrees C). Unprocessed controls were also included for comparison. RESULTS: Pulse lavage with 0.8 L saline alone removed 80% of the fat from the bone, whereas 95% of the fat was removed when washing was performed with 1.6 L of saline. The cleansing efficacy was improved further when an additional wash with warm water was used. INTERPRETATION: Our results indicate that pulse-lavage washing alone at room temperature is an effective method for defatting of morselized allograft bone, but an additional wash with warm water improves the cleansing efficiency. Pulse lavage is easily available and simple to use in the operating theater.

Development of supercritical fluid extraction with a solid-phase trapping for fast estimation of toxic load of polychlorinated dibenzo-p-dioxins-dibenzofurans in sawmill soil.

A method consisting of automated supercritical fluid extraction (SFE) with simultaneous cleanup by a solid-phase trap was developed for fast analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in soil. SFE was optimised to replace conventional liquid-based methods in routine analyses of PCDD/PCDFs in sawmill soil contaminated by a chlorophenol formulation. PCDD/PCDFs were quantitatively extracted in 60 min using CO2 at 400 atm and 100 degrees C without a modifier. A trap containing a small amount of activated carbon mixed with Celite efficiently collected PCDD/PCDFs after SFE. After SFE co-extracted impurities were eluted out from the trap with 4 ml of hexane and PCDD/PCDFs were eluted with 10 ml of toluene. The concentrations and TCDD-equivalent of PCDD/PCDFs corresponded to the results of traditional solvent extraction method (Soxhlet) in six sawmill soils tested. The performance of the trap was maintained over a long period of time (nearly 100 extractions).

Comparison of SFE with Soxhlet in the analyses of PCDD/PCDFs and PCBs in sediment.

The efficiency of supercritical fluid extraction (SFE) for the isolation of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) from sediments was investigated by comparing SFE with Soxhlet. Five sediments obtained from an international interlaboratory study were used as a test material. SFE was performed with an automatic system where extracted analytes were collected by solid-phase trapping using carbon mixed with Celite as an adsorbent. For the first time, SFE of the most toxic PCBs, coplanar PCBs, was studied with real sediment samples. The majority of PCBs investigated, a total of 38 congeners from tri- to decachlorinated, were quantitatively extracted from sediment by SFE with pure CO2 at pressure 400 atm and temperature 100 degrees C. Under these conditions a successful extraction was obtained also for PCDD/PCDFs except for hepta- and octachlorinated congeners. Copper powder added to the sediment efficiently prevented the transfer of sulfur from the sample during SFE. The TEQs of both PCDD/PCDFs and PCBs obtained by SFE corresponded well with those obtained by the Soxhlet-based method. The reproducibility of SFE was high for both groups.