4 research outputs found
ΠΠ°Π»ΠΈΠ΄Π°ΡΠΈΡ ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊΠΈ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΡ ΡΠ²Π΅ΡΠ° ΠΎΠΊΡΠ°ΡΠ΅Π½Π½ΡΡ Π²ΠΎΠ»ΠΎΠΊΠΎΠ½ Π½Π° ΠΌΠΈΠΊΡΠΎΡΠΊΠΎΠΏΠ΅-ΡΠΏΠ΅ΠΊΡΡΠΎΡΠΎΡΠΎΠΌΠ΅ΡΡΠ΅ ΠΠ‘Π€Π£-Π
This work is part of a series of efforts towards validation of methods used in forensic fiber analysis. These efforts address current needs for accreditation of forensic laboratories and quality control in operations.The qualitative testing methodology consists of obtaining absorption spectra with the microscope spectrophotometer MSFU-K and comparing the spectral characteristics of color in fiber samples. The expert determines whether the textile fibers submitted for analysis match in color or not, depending on the results of spectral comparison.The proposed validation experiment algorithm is designed for evaluating uncertainty in optical density measurements and the level of expert competence.In this case uncertainty corresponds to reproducibility standard deviation. To evaluate uncertainty, two operators took readings of absorption spectra of dyed fibers independently in the course of three days, and measured optical density at maximum and minimum absorption wavelengths. To evaluate repeatability, 5 spectra were obtained in a row on each of the three days.The testing was conducted using three samples of polyacrylonitrile (PAN) fibers. Key characteristic points in the samplesβ absorption spectra covered a wide range of wavelengths in the visible spectrum. Measurements were taken using the MSFU-K microspectrophotometer, which consists of a microscope with a spectrophotometric add-on unit.Statistical analysis of measurement data demonstrated uncertainty levels between 7,1 % and 22,1 %. Uncertainty values below 30 % are indicative of quantitative measurements and insignificant variance of optical density values, which corresponds to high reproducibility of spectra and allows the expert to make statistically reliable match/non-match conclusions on the color of compared fibers.Expert competence was assessed based on Β«blindΒ» test results. The experts had to determine which of the three samples were colored with the same dye. Each of the two experts was provided with 3 visually identical samples that were colored with different dyes. The experts were asked to distinguish between fibers treated with the same dye. When analyzing obtained spectra, both experts correctly identified same-color fibers based on matching color spectral characteristics.Positive validation results suggest that the MSFU-K microscope spectrophotometer can be successfully used in forensic fiber analysis for measuring the color of dyed fibers.Β Π‘ΡΠ°ΡΡΡ ΠΈΠ· ΡΠ΅ΡΠΈΠΈ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΎΠΊ ΠΏΠΎ Π²Π°Π»ΠΈΠ΄Π°ΡΠΈΠΈ ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊ, ΠΏΡΠΈΠΌΠ΅Π½ΡΠ΅ΠΌΡΡ
ΠΏΡΠΈ ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΡΡΠ²Π΅ ΠΊΡΠΈΠΌΠΈΠ½Π°Π»ΠΈΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠΊΡΠΏΠ΅ΡΡΠΈΠ·Ρ Π²ΠΎΠ»ΠΎΠΊΠ½ΠΈΡΡΡΡ
ΠΌΠ°ΡΠ΅ΡΠΈΠ°Π»ΠΎΠ².Π‘ΡΡΠ½ΠΎΡΡΡ ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎΠΉ ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊΠΈ ΡΠ΅ΡΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π·Π°ΠΊΠ»ΡΡΠ°Π΅ΡΡΡ Π² ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΈΠΈ Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΡΠΏΠ΅ΠΊΡΡΠΎΡΠΎΡΠΎΠΌΠ΅ΡΡΠ° ΠΠ‘Π€Π£-Π ΡΠΏΠ΅ΠΊΡΡΠ° ΠΏΠΎΠ³Π»ΠΎΡΠ΅Π½ΠΈΡ ΠΈ ΡΠΎΠΏΠΎΡΡΠ°Π²Π»Π΅Π½ΠΈΠΈ ΡΠΏΠ΅ΠΊΡΡΠ°Π»ΡΠ½ΡΡ
Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊ ΡΠ²Π΅ΡΠ° ΡΡΠ°Π²Π½ΠΈΠ²Π°Π΅ΠΌΡΡ
Π²ΠΎΠ»ΠΎΠΊΠΎΠ½. ΠΠ° ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠΈ ΡΠΎΠΏΠΎΡΡΠ°Π²Π»Π΅Π½ΠΈΡ ΡΠΏΠ΅ΠΊΡΡΠΎΠ² ΡΠΊΡΠΏΠ΅ΡΡ ΡΠ΅ΡΠ°Π΅Ρ Π²ΠΎΠΏΡΠΎΡ, ΡΠΎΠ²ΠΏΠ°Π΄Π°Π΅Ρ/Π½Π΅ ΡΠΎΠ²ΠΏΠ°Π΄Π°Π΅Ρ ΡΠ²Π΅Ρ ΡΡΠ°Π²Π½ΠΈΠ²Π°Π΅ΠΌΡΡ
Π²ΠΎΠ»ΠΎΠΊΠΎΠ½, ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Π½ΡΡ
Π½Π° ΡΠΊΡΠΏΠ΅ΡΡΠΈΠ·Ρ.ΠΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π° ΡΡ
Π΅ΠΌΠ° ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ° Π²Π°Π»ΠΈΠ΄Π°ΡΠΈΠΈ, Π·Π°Π΄Π°ΡΠ°ΠΌΠΈ ΠΊΠΎΡΠΎΡΠΎΠ³ΠΎ ΡΠ²Π»ΡΠ»ΠΈΡΡ ΠΎΡΠ΅Π½ΠΊΠ° Π½Π΅ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΠΎΡΡΠΈ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΡ ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ ΠΈ ΡΡΠΎΠ²Π½Ρ ΠΊΠΎΠΌΠΏΠ΅ΡΠ΅Π½ΡΠ½ΠΎΡΡΠΈ ΡΠΊΡΠΏΠ΅ΡΡΠΎΠ².Π ΡΠ°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°Π΅ΠΌΠΎΠΌ ΡΠ»ΡΡΠ°Π΅ Π½Π΅ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΠΎΡΡΡ ΡΠΎΠ²ΠΏΠ°Π΄Π°Π΅Ρ ΡΠΎ ΡΡΠ΅Π΄Π½Π΅ΠΊΠ²Π°Π΄ΡΠ°ΡΠΈΡΠ½ΡΠΌ ΠΎΡΠΊΠ»ΠΎΠ½Π΅Π½ΠΈΠ΅ΠΌ (Π‘ΠΠ) Π²ΠΎΡΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠΌΠΎΡΡΠΈ. ΠΠ»Ρ ΠΎΡΠ΅Π½ΠΊΠΈ Π½Π΅ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΠΎΡΡΠΈ Π΄Π²Π° ΠΎΠΏΠ΅ΡΠ°ΡΠΎΡΠ° ΡΠ½ΠΈΠΌΠ°Π»ΠΈ Π½Π΅Π·Π°Π²ΠΈΡΠΈΠΌΠΎ Π² ΡΠ΅ΡΠ΅Π½ΠΈΠ΅ ΡΡΠ΅Ρ
Π΄Π½Π΅ΠΉ ΡΠΏΠ΅ΠΊΡΡΡ ΠΏΠΎΠ³Π»ΠΎΡΠ΅Π½ΠΈΡ ΠΎΠ±ΡΠ°Π·ΡΠΎΠ² ΠΎΠΊΡΠ°ΡΠ΅Π½Π½ΡΡ
Π²ΠΎΠ»ΠΎΠΊΠΎΠ½ ΠΈ ΠΈΠ·ΠΌΠ΅ΡΡΠ»ΠΈ ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΡΡ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΡ Π² ΡΠΎΡΠΊΠ°Ρ
ΠΌΠ°ΠΊΡΠΈΠΌΡΠΌΠ° ΠΈ ΠΌΠΈΠ½ΠΈΠΌΡΠΌΠ°. ΠΠΎΠ²ΡΠΎΡΡΠ΅ΠΌΠΎΡΡΡ ΠΎΡΠ΅Π½ΠΈΠ²Π°Π»ΠΈ, ΡΠ½ΠΈΠΌΠ°Ρ Π² ΠΊΠ°ΠΆΠ΄ΡΠΉ ΠΈΠ· ΡΡΠ΅Ρ
Π΄Π½Π΅ΠΉ ΠΏΠΎ ΠΏΡΡΡ ΡΠΏΠ΅ΠΊΡΡΠΎΠ² ΠΏΠΎΠ΄ΡΡΠ΄.ΠΠ»Ρ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ Π±ΡΠ»ΠΈ Π²ΡΠ±ΡΠ°Π½Ρ ΡΡΠΈ ΠΎΠ±ΡΠ°Π·ΡΠ° ΠΎΠΊΡΠ°ΡΠ΅Π½Π½ΡΡ
ΠΏΠΎΠ»ΠΈΠ°ΠΊΡΠΈΠ»ΠΎΠ½ΠΈΡΡΠΈΠ»ΡΠ½ΡΡ
Π²ΠΎΠ»ΠΎΠΊΠΎΠ½ (Π½ΠΈΡΡΠΎΠ½). ΠΡΠ½ΠΎΠ²Π½ΡΠ΅ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΠΎΡΠΊΠΈ ΡΠΏΠ΅ΠΊΡΡΠΎΠ² ΠΏΠΎΠ³Π»ΠΎΡΠ΅Π½ΠΈΡ ΠΎΠ±ΡΠ°Π·ΡΠΎΠ² ΠΎΡ
Π²Π°ΡΡΠ²Π°ΡΡ ΡΠΈΡΠΎΠΊΡΡ ΠΎΠ±Π»Π°ΡΡΡ Π΄Π»ΠΈΠ½ Π²ΠΎΠ»Π½ Π²ΠΈΠ΄ΠΈΠΌΠΎΠ³ΠΎ ΡΠΏΠ΅ΠΊΡΡΠ°. ΠΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΡ Π²ΡΠΏΠΎΠ»Π½ΡΠ»ΠΈ Π½Π° ΠΌΠΈΠΊΡΠΎΡΠΏΠ΅ΠΊΡΡΠΎΡΠΎΡΠΎΠΌΠ΅ΡΡΠ΅ ΠΠ‘Π€Π£-Π, ΠΊΠΎΡΠΎΡΡΠΉ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»ΡΠ΅Ρ ΡΠΎΠ±ΠΎΠΉ ΠΌΠΈΠΊΡΠΎΡΠΊΠΎΠΏ ΡΠΎ ΡΠΏΠ΅ΠΊΡΡΠΎΡΠΎΡΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ Π½Π°ΡΠ°Π΄ΠΊΠΎΠΉ.Π ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠ΅ ΡΡΠ°ΡΠΈΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΠΉ ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ ΡΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ, ΡΡΠΎ Π½Π΅ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΠΎΡΡΡ Π²Π°ΡΡΠΈΡΡΠ΅Ρ ΠΎΡ 7,1 Π΄ΠΎ 22,1 %. ΠΠ½Π°ΡΠ΅Π½ΠΈΡ Π½Π΅ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΠΎΡΡΠΈ <30 % ΡΠΊΠ°Π·ΡΠ²Π°ΡΡ Π½Π° ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΠΉ Ρ
Π°ΡΠ°ΠΊΡΠ΅Ρ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΠΉ, Π½Π΅ΡΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΠΉ ΡΠ°Π·Π±ΡΠΎΡ Π·Π½Π°ΡΠ΅Π½ΠΈΠΉ ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ, ΡΡΠΎ ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΡΠ΅Ρ Π²ΡΡΠΎΠΊΠΎΠΉ Π²ΠΎΡΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠΌΠΎΡΡΠΈ ΡΠΏΠ΅ΠΊΡΡΠ° ΠΈ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΠ΅Ρ ΡΠΊΡΠΏΠ΅ΡΡΡ Π΄Π΅Π»Π°ΡΡ Π΄ΠΎΡΡΠΎΠ²Π΅ΡΠ½ΡΠ΅ Π²ΡΠ²ΠΎΠ΄Ρ ΠΎ ΡΠΎΠ²ΠΏΠ°Π΄Π΅Π½ΠΈΠΈ/Π½Π΅ΡΠΎΠ²ΠΏΠ°Π΄Π΅Π½ΠΈΠΈ ΡΠ²Π΅ΡΠ° ΡΡΠ°Π²Π½ΠΈΠ²Π°Π΅ΠΌΡΡ
Π²ΠΎΠ»ΠΎΠΊΠΎΠ½.ΠΠΎΠΌΠΏΠ΅ΡΠ΅Π½ΡΠ½ΠΎΡΡΡ ΡΠΊΡΠΏΠ΅ΡΡΠΎΠ² ΠΎΡΠ΅Π½ΠΈΠ²Π°Π»ΠΈ ΠΏΠΎ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠ°ΠΌ Β«ΡΠ»Π΅ΠΏΡΡ
Β» ΠΈΡΠΏΡΡΠ°Π½ΠΈΠΉ. ΠΠΊΡΠΏΠ΅ΡΡΡ Π΄ΠΎΠ»ΠΆΠ½Ρ Π±ΡΠ»ΠΈ ΡΡΡΠ°Π½ΠΎΠ²ΠΈΡΡ, ΠΊΠ°ΠΊΠΈΠ΅ ΠΈΠ· ΡΡΠ΅Ρ
ΠΎΠ±ΡΠ°Π·ΡΠΎΠ² Π²ΠΎΠ»ΠΎΠΊΠΎΠ½ ΠΎΠΊΡΠ°ΡΠ΅Π½Ρ ΠΎΠ΄Π½ΠΈΠΌ ΠΊΡΠ°ΡΠΈΡΠ΅Π»Π΅ΠΌ. ΠΠ²ΡΠΌ ΡΠΊΡΠΏΠ΅ΡΡΠ°ΠΌ Π±ΡΠ»ΠΈ ΠΏΡΠ΅Π΄ΠΎΡΡΠ°Π²Π»Π΅Π½Ρ ΠΏΠΎ ΡΡΠΈ ΠΎΠ±ΡΠ°Π·ΡΠ°, ΠΊΠΎΡΠΎΡΡΠ΅ ΠΏΠΎ ΡΠ²Π΅ΡΡ Π²ΠΈΠ·ΡΠ°Π»ΡΠ½ΠΎ ΠΏΡΠ°ΠΊΡΠΈΡΠ΅ΡΠΊΠΈ Π½Π΅ ΡΠ°Π·Π»ΠΈΡΠ°Π»ΠΈΡΡ, Π½ΠΎ Π±ΡΠ»ΠΈ ΠΎΠΊΡΠ°ΡΠ΅Π½Ρ ΡΠ°Π·Π½ΡΠΌΠΈ ΠΊΡΠ°ΡΠΈΡΠ΅Π»ΡΠΌΠΈ. ΠΠ΅ΡΠ΅Π΄ ΡΠΊΡΠΏΠ΅ΡΡΠ°ΠΌΠΈ ΡΡΠ°Π²ΠΈΠ»Π°ΡΡ Π·Π°Π΄Π°ΡΠ° Π΄ΠΈΡΡΠ΅ΡΠ΅Π½ΡΠΈΡΠΎΠ²Π°ΡΡ Π²ΠΎΠ»ΠΎΠΊΠ½Π°, ΠΎΠΊΡΠ°ΡΠ΅Π½Π½ΡΠ΅ ΠΎΠ΄Π½ΠΈΠΌ ΠΊΡΠ°ΡΠΈΡΠ΅Π»Π΅ΠΌ. ΠΡΠΈ Π°Π½Π°Π»ΠΈΠ·Π΅ ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΡ
ΡΠΏΠ΅ΠΊΡΡΠΎΠ² ΠΊΠ°ΠΆΠ΄ΡΠΌ ΡΠΊΡΠΏΠ΅ΡΡΠΎΠΌ Π±ΡΠ»ΠΈ ΡΠ΄Π΅Π»Π°Π½Ρ ΠΏΡΠ°Π²ΠΈΠ»ΡΠ½ΡΠ΅ Π²ΡΠ²ΠΎΠ΄Ρ ΠΎΠ± ΠΎΠ΄Π½ΠΎΡΠ²Π΅ΡΠ½ΡΡ
Π²ΠΎΠ»ΠΎΠΊΠ½Π°Ρ
, ΡΠΎΠ²ΠΏΠ°Π΄Π°ΡΡΠΈΡ
ΠΏΠΎ ΡΠΏΠ΅ΠΊΡΡΠ°Π»ΡΠ½ΡΠΌ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌ ΡΠ²Π΅ΡΠ°.ΠΠ° ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠΈ ΠΏΠΎΠ»ΠΎΠΆΠΈΡΠ΅Π»ΡΠ½ΡΡ
ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠ² Π²Π°Π»ΠΈΠ΄Π°ΡΠΈΠΎΠ½Π½ΠΎΠ³ΠΎ ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ° ΡΠ΄Π΅Π»Π°Π½ Π²ΡΠ²ΠΎΠ΄ ΠΎ ΠΏΡΠΈΠ³ΠΎΠ΄Π½ΠΎΡΡΠΈ ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊΠΈ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΡ ΡΠ²Π΅ΡΠ° ΠΎΠΊΡΠ°ΡΠ΅Π½Π½ΡΡ
Π²ΠΎΠ»ΠΎΠΊΠΎΠ½ Π½Π° ΠΌΠΈΠΊΡΠΎΡΠΊΠΎΠΏΠ΅-ΡΠΏΠ΅ΠΊΡΡΠΎΡΠΎΡΠΎΠΌΠ΅ΡΡΠ΅ ΠΠ‘Π€Π£-Π Π΄Π»Ρ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΡ Π² ΠΊΡΠΈΠΌΠΈΠ½Π°Π»ΠΈΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠΊΡΠΏΠ΅ΡΡΠΈΠ·Π΅ Π²ΠΎΠ»ΠΎΠΊΠ½ΠΈΡΡΡΡ
ΠΌΠ°ΡΠ΅ΡΠΈΠ°Π»ΠΎΠ².
Experimental Validation of a Methodology for Determining Soil pH and Specific Electrical Conductance in Samples of Geological and Soil Evidence in Forensic Environmental Investigations in the Absence of Standard Samples
The paper describes an experiment in validation of a forensic methodology for determining the hydrogen potential (pH) and specific conductance (SC) in samples of geological and soil evidence for the purposes of forensic environmental investigation. Validation was aimed at standardizing the conditions of aqueous extract preparation, since the conditions prescribed by corresponding regulations varied significantly. Given the absence of adequate standard samples at the time of the experiment, control samples had to be selected, and reference values of pH and SC in these control samples had to be determined through average values of the overall set of measurements. The experiment consisted of 5 operators independently conducting six parallel analyses of three control samples, each operator working at a different time and using their own assay kits. Both pH and SC values were measured in two different dilutions, each after 5 minutes, 1 hour, and 24 hours of holding time. Statistical calculations of the obtained set of results yielded reference values for target parameters in three control samples for different aqueous extract preparation conditions. It was demonstrated that when the extract is diluted to 1 : 2.5 soil/water ratio, measurements are on average 1.8 times higher for SC, and 0.20 pts lower for pH, compared to 1 : 5 soil/water dilution. Since 1 : 5 is the standard dilution for aqueous extracts, 1 : 2.5 dilutions call for a corresponding adjustment. Acceptable holding time between dilution and measurement has been established to vary between 5 minutes and 1 hour. When re-validated a year later, the obtained mean values of pH and SC in three control samples of soil fit within the uncertainty interval for adopted reference values.The outcomes demonstrate the stability of control sample properties and reliability of the applied methodology
Measuring Dyed Fiber Color with MSFU-K Microscope Spectrophotometer: Methodology Validation
This work is part of a series of efforts towards validation of methods used in forensic fiber analysis. These efforts address current needs for accreditation of forensic laboratories and quality control in operations.The qualitative testing methodology consists of obtaining absorption spectra with the microscope spectrophotometer MSFU-K and comparing the spectral characteristics of color in fiber samples. The expert determines whether the textile fibers submitted for analysis match in color or not, depending on the results of spectral comparison.The proposed validation experiment algorithm is designed for evaluating uncertainty in optical density measurements and the level of expert competence.In this case uncertainty corresponds to reproducibility standard deviation. To evaluate uncertainty, two operators took readings of absorption spectra of dyed fibers independently in the course of three days, and measured optical density at maximum and minimum absorption wavelengths. To evaluate repeatability, 5 spectra were obtained in a row on each of the three days.The testing was conducted using three samples of polyacrylonitrile (PAN) fibers. Key characteristic points in the samplesβ absorption spectra covered a wide range of wavelengths in the visible spectrum. Measurements were taken using the MSFU-K microspectrophotometer, which consists of a microscope with a spectrophotometric add-on unit.Statistical analysis of measurement data demonstrated uncertainty levels between 7,1 % and 22,1 %. Uncertainty values below 30 % are indicative of quantitative measurements and insignificant variance of optical density values, which corresponds to high reproducibility of spectra and allows the expert to make statistically reliable match/non-match conclusions on the color of compared fibers.Expert competence was assessed based on Β«blindΒ» test results. The experts had to determine which of the three samples were colored with the same dye. Each of the two experts was provided with 3 visually identical samples that were colored with different dyes. The experts were asked to distinguish between fibers treated with the same dye. When analyzing obtained spectra, both experts correctly identified same-color fibers based on matching color spectral characteristics.Positive validation results suggest that the MSFU-K microscope spectrophotometer can be successfully used in forensic fiber analysis for measuring the color of dyed fibers
ΠΡΠ°ΠΊΡΠΈΠΊΠ° Π²Π°Π»ΠΈΠ΄Π°ΡΠΈΠΈ ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊΠΈ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ pH ΠΈ ΡΠ΄Π΅Π»ΡΠ½ΠΎΠΉ ΡΠ»Π΅ΠΊΡΡΠΎΠΏΡΠΎΠ²ΠΎΠ΄Π½ΠΎΡΡΠΈ Π² ΠΎΠ±ΡΠ΅ΠΊΡΠ°Ρ ΠΏΠΎΡΠ²Π΅Π½Π½ΠΎ-Π³Π΅ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΏΡΠΎΠΈΡΡ ΠΎΠΆΠ΄Π΅Π½ΠΈΡ Π΄Π»Ρ ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΡΡΠ²Π° ΡΡΠ΄Π΅Π±Π½ΠΎ-ΡΠΊΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠΊΡΠΏΠ΅ΡΡΠΈΠ·Ρ ΠΏΡΠΈ ΠΎΡΡΡΡΡΡΠ²ΠΈΠΈ ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΡΡ ΠΎΠ±ΡΠ°Π·ΡΠΎΠ²
The paper describes an experiment in validation of a forensic methodology for determining the hydrogen potential (pH) and specific conductance (SC) in samples of geological and soil evidence for the purposes of forensic environmental investigation. Validation was aimed at standardizing the conditions of aqueous extract preparation, since the conditions prescribed by corresponding regulations varied significantly. Given the absence of adequate standard samples at the time of the experiment, control samples had to be selected, and reference values of pH and SC in these control samples had to be determined through average values of the overall set of measurements. The experiment consisted of 5 operators independently conducting six parallel analyses of three control samples, each operator working at a different time and using their own assay kits. Both pH and SC values were measured in two different dilutions, each after 5 minutes, 1 hour, and 24 hours of holding time. Statistical calculations of the obtained set of results yielded reference values for target parameters in three control samples for different aqueous extract preparation conditions. It was demonstrated that when the extract is diluted to 1 : 2.5 soil/water ratio, measurements are on average 1.8 times higher for SC, and 0.20 pts lower for pH, compared to 1 : 5 soil/water dilution. Since 1 : 5 is the standard dilution for aqueous extracts, 1 : 2.5 dilutions call for a corresponding adjustment. Acceptable holding time between dilution and measurement has been established to vary between 5 minutes and 1 hour. When re-validated a year later, the obtained mean values of pH and SC in three control samples of soil fit within the uncertainty interval for adopted reference values.The outcomes demonstrate the stability of control sample properties and reliability of the applied methodology.ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ΠΎ ΠΎΠΏΠΈΡΠ°Π½ΠΈΠ΅ ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ° ΠΏΠΎ Π²Π°Π»ΠΈΠ΄Π°ΡΠΈΠΈ ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊΠΈ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ Π²ΠΎΠ΄ΠΎΡΠΎΠ΄Π½ΠΎΠ³ΠΎ ΠΏΠΎΠΊΠ°Π·Π°ΡΠ΅Π»Ρ (pH) ΠΈ ΡΠ΄Π΅Π»ΡΠ½ΠΎΠΉ ΡΠ»Π΅ΠΊΡΡΠΎΠΏΡΠΎΠ²ΠΎΠ΄Π½ΠΎΡΡΠΈ (Π£ΠΠ) Π² ΠΎΠ±ΡΠ΅ΠΊΡΠ°Ρ
ΠΏΠΎΡΠ²Π΅Π½Π½ΠΎ-Π³Π΅ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΏΡΠΎΠΈΡΡ
ΠΎΠΆΠ΄Π΅Π½ΠΈΡ Π΄Π»Ρ ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΡΡΠ²Π° ΡΡΠ΄Π΅Π±Π½ΠΎ-ΡΠΊΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠΊΡΠΏΠ΅ΡΡΠΈΠ·Ρ. ΠΠ°Π΄Π°ΡΠ΅ΠΉ Π²Π°Π»ΠΈΠ΄Π°ΡΠΈΠΈ Π±ΡΠ»Π° ΡΠ½ΠΈΡΠΈΠΊΠ°ΡΠΈΡ ΡΡΠ»ΠΎΠ²ΠΈΠΉ ΠΏΡΠΈΠ³ΠΎΡΠΎΠ²Π»Π΅Π½ΠΈΡ Π²ΠΎΠ΄Π½ΠΎΠΉ Π²ΡΡΡΠΆΠΊΠΈ ΠΈΠ· ΠΈΡΡΠ»Π΅Π΄ΡΠ΅ΠΌΡΡ
ΠΎΠ±ΡΠ΅ΠΊΡΠΎΠ², ΠΏΠΎΡΠΊΠΎΠ»ΡΠΊΡ Π² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΡΡΡΠΈΡ
ΡΠ΅Π³Π»Π°ΠΌΠ΅Π½ΡΠΈΡΡΡΡΠΈΡ
Π½ΠΎΡΠΌΠ°ΡΠΈΠ²Π½ΡΡ
Π΄ΠΎΠΊΡΠΌΠ΅Π½ΡΠ°Ρ
ΡΡΠ»ΠΎΠ²ΠΈΡ ΡΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎ ΡΠ°Π·Π»ΠΈΡΠ°Π»ΠΈΡΡ. Π ΡΠ²ΡΠ·ΠΈ Ρ ΠΎΡΡΡΡΡΡΠ²ΠΈΠ΅ΠΌ Π½Π° ΡΠ΅ΠΊΡΡΠΈΠΉ ΠΌΠΎΠΌΠ΅Π½Ρ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΡΡ
ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΡΡ
ΠΎΠ±ΡΠ°Π·ΡΠΎΠ² Π²ΠΎΠ·Π½ΠΈΠΊΠ»Π° Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎΡΡΡ ΠΏΠΎΠ΄Π±ΠΎΡΠ° ΠΊΠΎΠ½ΡΡΠΎΠ»ΡΠ½ΡΡ
ΠΎΠ±ΡΠ°Π·ΡΠΎΠ² ΠΈ ΠΎΡΠ΅Π½ΠΊΠΈ Π² Π½ΠΈΡ
ΠΎΠΏΠΎΡΠ½ΡΡ
Π·Π½Π°ΡΠ΅Π½ΠΈΠΉ pH ΠΈ Π£ΠΠ ΠΊΠ°ΠΊ ΡΡΠ΅Π΄Π½ΠΈΡ
Π·Π½Π°ΡΠ΅Π½ΠΈΠΉ ΡΠΎΠ²ΠΎΠΊΡΠΏΠ½ΠΎΡΡΠΈ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠ² ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΠΉ. Π ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ΅ ΡΡΠ°ΡΡΠ²ΠΎΠ²Π°Π»ΠΈ ΠΏΡΡΡ ΠΎΠΏΠ΅ΡΠ°ΡΠΎΡΠΎΠ², ΠΊΠΎΡΠΎΡΡΠ΅ Π½Π΅Π·Π°Π²ΠΈΡΠΈΠΌΠΎ Π΄ΡΡΠ³ ΠΎΡ Π΄ΡΡΠ³Π° ΠΏΡΠΎΠ²ΠΎΠ΄ΠΈΠ»ΠΈ ΠΏΠΎ ΡΠ΅ΡΡΡ ΠΏΠ°ΡΠ°Π»Π»Π΅Π»ΡΠ½ΡΡ
Π°Π½Π°Π»ΠΈΠ·ΠΎΠ² ΡΡΠ΅Ρ
ΠΊΠΎΠ½ΡΡΠΎΠ»ΡΠ½ΡΡ
ΠΎΠ±ΡΠ°Π·ΡΠΎΠ², ΠΊΠ°ΠΆΠ΄ΡΠΉ ΠΎΠΏΠ΅ΡΠ°ΡΠΎΡ - Π² ΡΠ°Π·Π½ΠΎΠ΅ Π²ΡΠ΅ΠΌΡ, ΡΠΎ ΡΠ²ΠΎΠΈΠΌ Π½Π°Π±ΠΎΡΠΎΠΌ ΡΠ΅Π°ΠΊΡΠΈΠ²ΠΎΠ² ΠΈ ΠΎΠ±ΠΎΡΡΠ΄ΠΎΠ²Π°Π½ΠΈΡ. ΠΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΡ pH ΠΈ Π£ΠΠ Π²ΡΠΏΠΎΠ»Π½ΡΠ»ΠΈ Π΄Π»Ρ Π΄Π²ΡΡ
ΡΠ°Π·Π²Π΅Π΄Π΅Π½ΠΈΠΉ, ΠΊΠ°ΠΆΠ΄ΠΎΠ΅ ΡΠ΅ΡΠ΅Π· 5 ΠΌΠΈΠ½, 1 ΡΠ°Ρ ΠΈ 24 ΡΠ°ΡΠ°. ΠΠ° ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠΈ ΡΡΠ°ΡΠΈΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠ°ΡΡΠ΅ΡΠΎΠ² ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΠΎΠΉ ΡΠΎΠ²ΠΎΠΊΡΠΏΠ½ΠΎΡΡΠΈ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠ² ΠΏΡΠΈΠ½ΡΡΡ ΠΎΠΏΠΎΡΠ½ΡΠ΅ Π·Π½Π°ΡΠ΅Π½ΠΈΡ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΠ΅ΠΌΡΡ
ΠΏΠΎΠΊΠ°Π·Π°ΡΠ΅Π»Π΅ΠΉ Π² ΡΡΠ΅Ρ
ΠΊΠΎΠ½ΡΡΠΎΠ»ΡΠ½ΡΡ
ΠΎΠ±ΡΠ°Π·ΡΠ°Ρ
ΠΏΡΠΈ ΡΠ°Π·Π½ΡΡ
ΡΡΠ»ΠΎΠ²ΠΈΡΡ
ΠΏΡΠΈΠ³ΠΎΡΠΎΠ²Π»Π΅Π½ΠΈΡ Π²ΠΎΠ΄Π½ΠΎΠΉ Π²ΡΡΡΠΆΠΊΠΈ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΠΏΡΠΈ ΡΠ°Π·Π²Π΅Π΄Π΅Π½ΠΈΠΈ Π²ΡΡΡΠΆΠΊΠΈ Π² ΡΠΎΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΠΈ ΠΏΠΎΡΠ²Π°/Π²ΠΎΠ΄Π° 1 :2,5 Π² ΡΡΠ΅Π΄Π½Π΅ΠΌ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ Π£ΠΠ Π²ΡΡΠ΅ Π² 1,8 ΡΠ°Π·Π°, Π° pH Π½ΠΈΠΆΠ΅ Π½Π° 0,20 Π΅Π΄. Π² ΡΡΠ°Π²Π½Π΅Π½ΠΈΠΈ Ρ ΡΠ°Π·Π²Π΅Π΄Π΅Π½ΠΈΠ΅ΠΌ ΠΏΠΎΡΠ²Π°/Π²ΠΎΠ΄Π° 1 : 5. ΠΠΎΡΠΊΠΎΠ»ΡΠΊΡ Π΄Π»Ρ Π²ΠΎΠ΄Π½ΠΎΠΉ Π²ΡΡΡΠΆΠΊΠΈ ΠΎΠ±ΡΠ΅ΠΏΡΠΈΠ½ΡΡΡΠΌ ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠ°Π·Π²Π΅Π΄Π΅Π½ΠΈΠ΅ 1 : 5, Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎ Π²Π²ΠΎΠ΄ΠΈΡΡ ΠΏΠΎΠΏΡΠ°Π²ΠΊΡ ΠΏΡΠΈ ΡΠ°Π·Π²Π΅Π΄Π΅Π½ΠΈΠΈ 1 : 2,5. Π ΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΠΈ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ Π²ΡΠ΄Π΅ΡΠΆΠΈΠ²Π°Π½ΠΈΡ Π²ΡΡΡΠΆΠΊΠΈ Π΄ΠΎ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΡ ΡΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ, ΡΡΠΎ ΠΎΠ½ΠΎ ΠΌΠΎΠΆΠ΅Ρ Π²Π°ΡΡΠΈΡΠΎΠ²Π°ΡΡΡΡ ΠΎΡ 5 ΠΌΠΈΠ½ Π΄ΠΎ 1 ΡΠ°ΡΠ°. ΠΡΠΈ ΠΏΠΎΠ²ΡΠΎΡΠ½ΠΎΠΉ Π²Π°Π»ΠΈΠ΄Π°ΡΠΈΠΈ ΡΠ΅ΡΠ΅Π· Π³ΠΎΠ΄ Π½Π°ΠΉΠ΄Π΅Π½Π½ΡΠ΅ ΡΡΠ΅Π΄Π½ΠΈΠ΅ Π·Π½Π°ΡΠ΅Π½ΠΈΡ pH ΠΈ Π£ΠΠ Π² ΡΡΠ΅Ρ
ΠΊΠΎΠ½ΡΡΠΎΠ»ΡΠ½ΡΡ
ΠΎΠ±ΡΠ°Π·ΡΠ°Ρ
ΠΏΠΎΡΠ²Π΅Π½Π½ΡΡ
ΠΎΠ±ΡΠ΅ΠΊΡΠΎΠ² Π½Π°Ρ
ΠΎΠ΄ΠΈΠ»ΠΈΡΡ Π² ΠΏΡΠ΅Π΄Π΅Π»Π°Ρ
ΠΈΠ½ΡΠ΅ΡΠ²Π°Π»Π° Π½Π΅ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΠΎΡΡΠΈ ΠΏΡΠΈΠ½ΡΡΡΡ
ΠΎΠΏΠΎΡΠ½ΡΡ
Π·Π½Π°ΡΠ΅Π½ΠΈΠΉ. ΠΠΎΠ»ΡΡΠ΅Π½Π½ΡΠ΅ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΡΠ²ΠΈΠ΄Π΅ΡΠ΅Π»ΡΡΡΠ²ΡΡΡ ΠΎΠ± ΡΡΡΠΎΠΉΡΠΈΠ²ΠΎΡΡΠΈ ΡΠ²ΠΎΠΉΡΡΠ² ΠΊΠΎΠ½ΡΡΠΎΠ»ΡΠ½ΡΡ
ΠΎΠ±ΡΠ°Π·ΡΠΎΠ² ΠΈ Π½Π°Π΄Π΅ΠΆΠ½ΠΎΡΡΠΈ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½Π½ΠΎΠΉ ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊΠΈ