Effect Of Sample Pretreatment Research Articles

Effects of sample pre-treatments on the analysis of liquid organic manures by visible and near-infrared spectrometry

Proper application of a fertilizer requires precise knowledge of its nutrient composition. In the case of liquid organic manures (LOM), this information is often lacking due to heterogeneous nature of these fertilizers. Published “book values” of nutrient contents present the average from a wide range of possible nutrient characteristics, but usually differ considerably from the concentration in a particular manure. Thus, chemical analyses are recommended before applying the specific LOM. Unfortunately, this is usually too costly and time-intensive in practical farming. On-farm analysis by optical spectrometry in the visible and near-infrared (Vis-NIR) range is considered as an efficient alternative. However, calibration of Vis-NIR spectrometry for LOM is challenging as shown in many studies. One reason is LOMs’ tendency to rapidly segregate into a fuzzy continuum with liquid and solid properties. By separating LOM into well-defined liquid and solid phases and measuring them separately, calibration of Vis-NIR spectrometry might be improved. In this study, the effects of four sample pre-treatment techniques on the prediction accuracy of macronutrients (N, P, K, Mg, Ca, S), micronutrients (B, Mn, Fe, Cu, Zn), dry matter and pH of LOM using visible and near infrared spectrometry were comprehensively investigated. The concentrations were referred either to wet basis or to dry matter basis. For the study, a total of 163 samples, separated in two similar LOM sets (pig, cattle, digestates), were either dried, filtered, or centrifuged and always compared to non-treated samples. The experiments demonstrate that in comparison to raw samples (Ø r2 = 0.85) neither filtering (Ø r2 = 0.76 for filtrates and Ø r2 = 0.71 for filter residues), centrifugation (Ø r2 = 0.59 for supernatants and Ø r2 = 0.79 for pellets), nor drying (Ø r2 = 0.74) revealed to be a helpful preparation step significantly improving prediction results, independent from referring to wet or dry basis concentrations.

The Effect of Sample Pretreatment on the Anthocyanin Content in Czech Wild Elderberry (Sambucus nigra L.).

This work focusses on the analysis of anthocyanins present in wild Czech elderberries, using spectrophotometric methods and liquid chromatography. Spectrophotometric methods were used to determine antioxidant capacity, total phenolic content, and total anthocyanin content. Further, four major elderberry anthocyanins were determined using reversed-phase high-performance liquid chromatography with isocratic elution of 30% aqueous methanol with 5% of formic acid. All optimised methods were applied to the analysis of extracts prepared from frozen and dried elderberry fruit samples, and the results were evaluated using principal component analysis which clearly divided the samples into individual groups according to the sample pretreatment (frozen and dried samples). The frozen samples reached higher values of antioxidant capacity and total phenolic and anthocyanin contents compared to the dried samples, probably due to the degradation of anthocyanins during the drying process.

Effect of sample pretreatment on pelletization and performance of laser-induced breakdown spectroscopy for predicting key soil properties

Laser-induced breakdown spectroscopy (LIBS) is a promising analytical technique for determining soil properties in a rapid, cost-effective, and environmentally friendly manner. However, an optimal sample pretreatment method that enhances sample homogeneity for improved prediction accuracy is needed. In this study, the effect of different sample pretreatments on pelletization of soil samples, and prediction of texture and soil organic carbon (SOC) content, was assessed. Four pretreatments, namely 2 mm, 200 μm, and 100 μm sieved, and milled pretreatment, were applied to 133 soil samples representing a wide variability in texture and SOC content range. Visual assessment of soil pellet surface quality was done where poor surfaces, deemed unsuitable for LIBS measurement, were separated from the good-surface pellets. Partial least square regression (PLSR) models for the pretreatments across the investigated soil properties were compared, followed by interval partial least square regression (iPLSR), to evaluate potential improvements in the accuracy of the prediction models. The ratio of performance to interquartile distance (RPIQ) was used to rank the PLSR models for each pretreatment across the soil properties. The 100 μm pretreatment had the highest number of good-surface pellets followed by the 2 mm pretreatment, and lastly the 200 μm and milled pretreatments, which were comparable. The milled pretreatment achieved the best model for sand prediction (RPIQ = 7), followed by the 2 mm pretreatment for clay prediction (RPIQ = 2.5), 100 μm pretreatment for silt prediction (RPIQ = 2), and the milled pretreatment for SOC prediction (RPIQ = 1). A reduction in RMSEP of 31%, 23%, and 11% for the prediction of sand, SOC, and silt content, respectively was achieved by the milled pretreatment while the 100 μm pretreatment recorded a 15% reduction in RMSEP for the prediction of silt content. Overall, PLSR performed better than iPLSR for the prediction of texture (apart from clay) and SOC. These results show that sample pretreatment that involves sieving, or milling, influences the pellet surface quality and the prediction accuracy of texture and SOC content.

New insights into SARS-CoV-2 Lumipulse G salivary antigen testing: accuracy, safety and short TAT enhance surveillance.

The rapid, accurate and safe detection of SARS-CoV-2 is the key to improving surveillance and infection containment. The aim of the present study was to ascertain whether, after heat/chemical inactivation, SARS-CoV-2N antigen chemiluminescence (CLEIA) assay insaliva remains a valid alternative to molecular testing. In 2022, 139 COVID-19 inpatients and 467 healthcare workers were enrolled. In 606 self-collected saliva samples (Salivette), SARS-CoV-2 was detected by molecular (TaqPath rRT-PCR) and chemiluminescent Ag assays (Lumipulse G). The effect of sample pre-treatment (extraction solution-ES or heating) on antigen recovery was verified. Salivary SARS-CoV-2 antigen assay was highly accurate (AUC=0.959, 95% CI: 0.943-0.974), with 90% sensitivity and 92% specificity. Of the 254 antigen positive samples, 29 were false positives. We demonstrated that heterophilic antibodies could be a cause of false positive results. A significant antigen concentration decrease was observed after ES treatment (p=0.0026), with misclassification of 43 samples. Heat had a minimal impact, after treatment the correct classification of cases was maintained. CLEIA SARS-CoV-2 salivary antigen provides accurate, timely and high-throughput results that remain accurate also after heat inactivation, thus ensuring a safer work environment. This supports the use of salivary antigen detection by CLEIA in surveillance programs.

Effectiveness of cranberry (Vaccinium macrocarpon, cv. Pilgrim) vacuum impregnation: The effect of sample pretreatment, pressure, and processing time

This study aimed to determine the effects of vacuum impregnation (VI) on the effectiveness of enrichment of cranberry fruit with ascorbic acid. During the research, different strategies of fruit preparation that might improve impregnation in a ternary solution containing ascorbic acid, citric acid, and sucrose were tested. The evaluation of the processes was based on an analysis of impregnation efficiency, selected quality parameters, and alterations of internal structure. The results confirm that VI proceeds efficiently with heat-treated or bisected cranberry. The pressure and length of the individual process stages also affect impregnation efficiency. The lower the pressure and/or the longer the impregnation time, the higher the ascorbic acid content in the fruit. It can be concluded that VI is an effective method for enriching difficult to process berries with valuable compounds.

Impact of common sample pre-treatments on key soil microbial properties

Pre-treatment of soil samples prior to analysis is acknowledged to affect microbial activity and community parameters, but recommendations are diverging and there are no best-practice or standardised laboratory protocols. For the microbial carbon use efficiency (CUE) as a ratio parameter of C allocated to anabolism over total metabolised C, the effects of sample pre-treatment are unpredictable because the underlying parameters of microbial metabolism may be affected differently. In treatment or land use comparisons, it is important to know whether soils are affected in a similar way by pre-treatment. Based on five different paired sites (each with cropland and forest), the effects of six common pre-treatments were evaluated on 18O-CUE and associated parameters, i.e. respiration rate, soil microbial biomass C, total DNA extracted, and estimated abundances of fungi, bacteria and archaea. The six common pre-treatments were: (i) immediate analysis of field-fresh soil samples, and analysis following 14 d pre-incubation of soil samples that were (ii) field-fresh, (iii) air-dried, (iv) oven-dried (40 °C), (v) frozen at −20 °C and (vi) frozen in-situ (dry ice and subsequently liquid N2). The experiment revealed two main findings. The first was that pre-incubation of 14 d had the most pronounced effect and reduced microbial respiration rate, growth rate and microbial biomass C by between 28% and 63% on average compared with field-fresh samples, suggesting an impact of the reduction in readily available substrates on microbial activity. The second finding was that even after 14 days of pre-incubation, drying & rewetting caused an increase in the microbial respiration rate in forest soil samples of 64 ± 53% (air-drying) and 86 ± 65% (oven-drying), known as the Birch effect. However, CUE as a ratio parameter was found to be unaffected by sample pre-treatment, with only minor changes after 14 d of pre-incubation. Pre-treatment (including pre-incubation) affected cropland and forest samples similarly, with one exception: the estimated abundance of fungi increased only with drying & rewetting in forest soils. This suggests that dried cropland soils could potentially yield appropriate community data, while forest soils respond to soil drying in a more complex way. It was concluded that CUE values can be derived from soil samples regardless of whether they were dried & rewetted, frozen & thawed, or stored fresh.

The role of pre-treatment in enhancing yield and antioxidant activity of lemongrass (Cymbopogun citratus) essential oil

Sample preparation before distillation is an important step in producing high yield and good quality of lemongrass (Cymbopogun sitratus) essential oil. In order to improve the production process and to provide information as reference for further practical applications, the effects of sample pre-treatment (with and without microwave heating) and distillation time (3, 4, and 5 h) were studied. In addition, the samples types (dried stem and dried leaf) were compared. Results of the study suggested that the highest antioxidant activity of lemongrass essential oil (86.33%) was obtained from lemongrass dried stem that were heated in microwave and distilled for 4 h with yield of 2.307%. While the highest yield of lemongrass essential oil produced (2.63%) was obtained from lemongrass dried stem that were heated in microwave and distilled for 5 h with antioxidant activity of 69.67%. Based on the results, it can be concluded that lemongrass stem contains higher essential oil compare to that of the leaf and microwave heating before distillation gave higher yield and better quality of the product.

Measuring Bacterial Growth Potential of Ultra-Low Nutrient Drinking Water Produced by Reverse Osmosis: Effect of Sample Pre-treatment and Bacterial Inoculum.

Measuring bacterial growth potential (BGP) involves sample pre-treatment and inoculation, both of which may introduce contaminants in ultra-low nutrient water (e.g., remineralized RO permeate). Pasteurization pre-treatment may lead to denaturing of nutrients, and membrane filtration may leach/remove nutrients into/from water samples. Inoculating remineralized RO permeate samples with natural bacteria from conventional drinking water leads to undesired nutrient addition, which could be avoided by using the remineralized RO permeate itself as inoculum. Therefore, this study examined the effect of pasteurization and membrane filtration on the BGP of remineralized RO permeate. In addition, the possibility of using bacteria from remineralized RO permeate as inoculum was investigated by evaluating their ability to utilize organic carbon that is readily available (acetate, glucose) or complex (laminarin, gelatin, and natural dissolved organic carbon), as compared with bacteria from conventional drinking water. The results showed that membrane filtration pre-treatment increased (140–320%) the BGP of remineralized RO permeate despite the extensive soaking and flushing of filters (>350 h), whereas no effect was observed on the BGP of conventional drinking water owing to its high nutrient content. Pasteurization pre-treatment had insignificant effects on the BGP of both water types. Remineralized RO permeate bacteria showed limitations in utilizing complex organic carbon compared with bacteria from conventional drinking water. In conclusion, the BGP bioassay for ultra-low nutrient water (e.g., remineralized RO permeate) should consider pasteurization pre-treatment. However, an inoculum comprising bacteria from remineralized RO permeate is not recommended as the bacterial consortium was shown to be limited in terms of the compounds they could utilize for growth.

Effects of sample pretreatment and particle size on the determination of nitrogen in soil by portable LIBS and potential use on robotic-borne remote Martian and agricultural soil analysis systems.

Field determination of nitrogen in soil is of interest for both terrestrial and Martian applications. Improved management of soil nitrogen levels on Earth could benefit global food production, whilst the determination of soil nitrogen on Mars is required to assess the planet's future habitability. In this study, a mobile laser induced breakdown spectroscopy (LIBS) system with a 1064 nm Nd:YAG laser delivering 25 mJ per pulse was used to assess the effects of sample pretreatment on the measurement of nitrogen in soil. Although pelletisation was preferred, simply milling the sample to <100 mm particle size – which may be more feasible on a remote rover-based analytical platform – improved the spectra obtained. Ablation craters formed in targets prepared from different particle size fractions of the same commercially-available topsoil showed a clear trend in morphology, with smaller particles yielding more uniform craters with fewer fractures. The LIBS emission intensity at 746.83 nm followed a similar trend to results obtained for total nitrogen content in the soil particle size fractions by microanalysis (Perkin Elmer CHN Elemental Analyser) and was well-correlated (R2 = 0.94) with soil nitrate determined by ion chromatography (Dionex DX-100). Although correlations were less good when analysing field soil samples collected from central Scotland (R2 = 0.82 for comparison between LIBS and microanalysis) the study nevertheless demonstrates the potential of portable LIBS for measurement of soil nitrogen content.

Effects of sample pretreatment and external contamination on bivalve shell and Carrara marble δ18O and δ13C signatures

Stable isotope signatures of bivalve shells serve as important paleoclimate proxies. However, such data can be biased as a consequence of physical and chemical sample pretreatment and contamination during sampling. As yet, the potential isotope error induced by paleontological preservation techniques and specific methods used in bivalve sclerochronology have not been systematically assessed. To address these issues, homogenized powder of a well-preserved, aragonitic fossil shell, Glycymeris obovata (ca. 30Ma old) as well as Carrara marble powder (calcite) were exposed to ultrasound, a set of different staining solutions and cleaning agents. In addition, these reference materials were artificially contaminated with increasing proportions of powder prepared from periostracum, Alcian Blue and cured adhesives. Whereas some treatments (rinsing with Milli-Q water, immersion in Alizarin Red S solution and possibly Mutvei's solution) did not affect the isotope values of the carbonate samples, severe isotope shifts were observed after immersing shell powder in Feigl's solution (Δδ18O=−0.62‰) and mixing Carrara marble powder with Gluetec Metal Epoxy (a contamination level of 41.7wt% shifted δ18O and δ13C values by −2.12‰ and −1.74‰, respectively). Increasing levels of Metal Epoxy in the sample resulted in a sharp, non-linear decrease of the isotope values. The majority of tested treatments conducted with the carbonate powders and contaminants added to them caused minor to moderate, mainly statistically significant isotope offsets (bleaching with NaOCl and H2O2; exposure to ethyl alcohol and Rewoquat W 3690 PG, a surfactant; ultrasonic cleaning; contamination with powder of Alcian Blue, cured superglue, several different polyepoxies, methacrylates and polyvinyl butyral resins as well as periostracum). In conclusion, pretreatment of bivalve shells with an intended use for isotope analysis should be kept at an absolute minimum and contamination with adhesives etc. should be avoided. Specimens from museum collections that underwent special conservation methods may be of limited value for isotope studies, unless the history of sample treatment is known. Although only a few of the tested substances and methods strongly biased the isotope signatures, even small changes can accumulate to levels that are inacceptable for high-resolution paleoclimatology.

Effect of sample pretreatment on the extraction of lemon (Citrus limon) components

A study on the key role of lemon sample pretreatment on the analytical results is here presented. The objective of the study was to analyze the differences between extracts obtained from lyophilized and air-dried samples—the most common sample pretreatment in citrus studies—in comparison to extracts from fresh samples. All the extracts were obtained with ultrasound assistance and analyzed by LC–QTOF MS/MS. The dataset, constituted by 74 tentative identified metabolites, was first evaluated by ANOVA, which showed significant differences in the concentration of 44 out of 74 metabolites (p≤0.01). Also, the pairwise mean comparison (Tukey HSD; p≤0.01) revealed that the concentration of metabolites in the extracts from fresh and air-dried samples was quite similar and differed from that in lyophilized samples. On the other hand, application of principal component analysis (PCA) showed a clear discrimination between pretreatments, explaining 86.20% of the total variability. The results of this study suggest that the main differences between extracts could be attributed to the effect of freezing or heating on metabolic pathways, and not only to thermolability of the compounds.

Effect of sample pre-treatment on isoflavones quantification in soybean

AbstractHigh performance liquid chromatography is the most common technique for analysing isoflavones in soy; however, the appropriate sample pre-treatment is required, including extraction and, often, hydrolysis. In the present work, the kinetics of extraction was investigated with regard to the number of extraction steps and their duration for the exhaustive extraction of bonded forms of isoflavones and aglycones. In addition, a systematic experimental study of hydrolysis depending on the temperature and acidity of the medium was conducted. The results showed that the assisted methods were more effective for the isolation of isoflavones. Moreover, the differences between the results obtained using ultrasound-assisted extraction (UAE), microwave-assisted extraction and pressurised liquid extraction were not statistically significant; however, the appropriate number of extraction steps and their duration for UAE were required. The investigation also revealed that, due to the varying susceptibility of glycosides on conversion to free forms and the stability of the aglycones obtained, two parallel hydrolysis procedures should be conducted to obtain the highest hydrolysis efficiency. The optimised conditions, taking into account the shortest time combined with the highest efficiency, were as follows: 4 M HCl and 60 min for genistein; 8 M HCl and 30 min for glycitein and daidzein.

Effect of sample pretreatment on the fractionation of arsenic in anoxic soils.

Using by sequential extraction procedures to obtain the chemical forms of arsenic in soils can provide useful information for the assessment of arsenic mobility and bioavailability in soils. However, sample pretreatments before the extraction probably have some effects on the fractionation of arsenic in soils. Impact of sample pretreatments (freeze-drying, oven-drying, air-drying, and the fresh soil) on the fractionation of arsenic in anoxic soils was investigated in this study. The results show that there are some differences for arsenic fractions in soils between by drying pretreatments and by the fresh soil, indicating that the redistribution among arsenic fractions in anoxic soils occurs after drying pretreatments. The redistribution of arsenic fractions in anoxic soils is ascribed to the oxidation of organic matter and sulfides, the crystallization of iron (hydr)oxides, the ageing process, and the diffusion of arsenic into micropores. The freeze-drying is the best drying method to minimize the effect on the fractionation of arsenic in anoxic soils, while air-drying is the worst one. Drying pretreatments are not recommended for the fractionation of arsenic in anoxic soils with high concentration of iron.

Effects of sample pretreatments on EPR spectral characteristics of irradiated sea algae – an advanced approach to identify irradiation status

Different sea algae, such as sea tangle, seaweed, and sea mustard were gamma-irradiated at 1, 5, and 10 kGy.

Separation of squalene and oil from Amaranthus seeds by supercritical carbon dioxide

Supercritical fluid extraction was used to obtain oil and squalene from Amaranthus seeds. Results of studies on selection of optimum condition for extraction by supercritical carbon dioxide i.e. pressure, temperature and time of process and effect of sample pre-treatment on extraction yield were presented. It was found that all these factors have a significant effect on the amount of isolated oil, content of squalene in it and yield of squalene. Extraction was carried out at temperature of 30–130°C, pressure of 10–30MPa and CO2 flow rate of 6.4–10.0lCO2/h. Among the conditions studied, the highest yield of the extracted oil (64% of the seeds) was obtained at higher pressure, low temperature and long time of extraction (30MPa, 40°C and 120min). Whereas, the highest content of squalene in the extract (60%) was obtained at lower pressure, higher temperature and short time of extraction (20MPa, 130°C and 30min). However, high recovery of squalene (>99%) from seeds is obtained at the same conditions of pressure and temperature but in significantly longer time of extraction (90min).

Understanding the dependence of contact angles of commercially RO membranes on external conditions and surface features

The contact angles of three kinds of typically commercial reverse osmosis (RO) membranes (LP21, ULP21, and FR11) were firstly investigated. The relationships between the contact angles and external conditions were researched by well considering the effects of sample pretreatment, water-droplet volume, environmental humidity, water temperature and salinity. Furthermore, the surface features of these RO membranes, including functional groups, surface roughness, and zeta potentials, were also analyzed for exploring their influences on the contact-angle values, by using attenuate total reflectance infrared (ATR-IR) spectra, scanning electronic microscopy (SEM), and streaming potential instrument. The experimental results suggest that the sample pretreatment makes the hydrophilicity of RO membranes decrease, because of the part removal of physically coated hydrophilic aliphatic alcohols and protect agents introduced in the synthesis process. The water-droplet volumes have no obvious effect on the contact-angle measurement results. The contact-angle values can be gradually decreased with the enhancements of the environmental humidity, external temperature, and water salinity. Moreover, it was found that the enhancements on the density of modified hydrophilic functional groups, surface roughness and surface zeta potential are favorable for the decrease of contact angles.

Effect of sample pretreatment on the fractionation of Fe, Cr, Ni, Cu, Mn, and Zn in acid sulfate soil materials

A sequential extraction procedure was applied to acid sulfate soil materials from a soil profile to investigate the effect of sample pretreatment on the geochemical fractionation of selected metals. The samples were prepared for analysis by oven-drying, sieving and grinding the soil, or were examined as collected in field condition. The soil profile encompassed oxidising conditions near the surface, through to reducing conditions at depth. Six metals (Fe, Cr, Ni, Mn, Cu, and Zn) were measured during the sequential extraction procedure, and their fractionation determined in the oxidised and in the reduced zone. Although cumulative totals (the sum of all steps in the sequential extraction procedure) for the metals extracted from both the field condition and dried/ground samples were similar, some significant differences in fractionation within individual extraction steps were observed. Of particular interest was the redistribution of metals from the sulfide-bearing (pyrite-bound) fraction to the more readily available fractions (i.e. labile and acid-soluble), as a result of oven-drying and grinding. The results indicate that when assessing metal fractionation in acid sulfate soil materials, samples should be analysed in field condition in order to avoid the considerable metal fractionation artifacts that are induced by drying and grinding.

Simple and rapid determination of phosphorus in meat samples by WD-XRF method

The wavelength dispersive X-ray fluorescence (WD-XRF) method for phosphorus determination in meat samples has been described. The effects of sample pretreatment on the XRF analysis have been discussed. The phosphorus content determined in meat samples ranged from 603 ± 6 to 613 ± 19 mg P/100g dry mass (d.m.), depending on the sample preparation technique. The meat samples spiked with phosphates have been used for the calibration procedure. The accuracy was determined against a number of certified reference materials (SMRD 2000, RF 8414, NIST-1568A, and NIST-1549), and recovery was assayed using the standard addition procedure. The proposed method has been compared with the standard spectrophotometric method (PN-ISO 13730, 1999) of total phosphorus determination. The sample pretreatment procedure has been reduced to minimum the presented results suggest the WD-XRF method can be an alternative to the spectrophotometric analysis.

Effect of sample pre-treatment on the determination of steroid esters in hair of bovine calves

The effect of three sample pre-treatment steps, washing, cutting and grinding on the determination of steroid esters in hair is studied. The study is performed by using hair samples obtained after pour-on application of steroid esters to bovine calves. After sample pre-treatment the hair is treated with a mild reducing agent [tris(2-carboxyethyl)phosphine hydrochloride] to extract the steroid esters. After a solid-phase extraction clean-up step the extracts are analysed by using liquid chromatography combined with triple–quadrupole mass spectrometric detection. For the washing step the use of non-organic washing solvents like (warm) water and a solution of 0.1% sodium dodecyl phosphate and organic solutions containing different percentages of methanol are tested. By using the non-organic solvents and the organic solvents with a percentage of methanol <20% the recovery results are as good as the results obtained without washing the hair. Cutting the hair samples increases the analyte recoveries of incurred steroid esters by 20% compared to the non-cut hair. The analyte recoveries of cut hair samples are about 60–80% that of ground hair samples. The obtained surface expansion of hair samples by grinding proves to be necessary in order to achieve the highest possible analyte yields. Finally the use of pressurised liquid extraction (PLE) for the extraction of steroid esters from plain (no washing, cutting or grinding) hair is investigated. The first results show lower (up to 40%) extraction recoveries in comparison with the classical solvent extraction procedures. If the limit of detection requirement is met, PLE may be an alternative for extracting large numbers of hair samples due to the short sample treatment procedure involved.

The precision of porosity measurements: Effects of sample pre-treatment on porosity measurements of modern and archaeological bone

Bone porosity plays an important role in the taphonomic trajectory of bones. Porosity analysis of archaeological material can indicate diagenetic events in the bones taphonomic history. Furthermore, measuring the porosity of modern bone material can potentially provide a method for assessing the relative likelihood of survival for different skeletal elements. Here we critically assess the use of nitrogen adsorption porosimetry and mercury intrusion porosimetry for analysing porosity of a range of bone preservation types; from modern fresh material to highly degraded archaeological material. In addition a number of sample preparation methods were assessed. Our results indicate that bone porosity measurements show large variation, which may limit their usefulness when analysing modern material. Features observed in pore size distribution graphs are, however, consistent and thus this data would appear to be a useful indicator of diagenetic processes that have occurred in the bone. The most effective method for preparation of the bone is lyophilisation which renders the bone dry enough for analysis and does not appear to cause a visible systematic error in the measurements.