scholarly journals Comparison of different methods used in drugs of abuse for sample validity testing including pH methods, specific gravity methods, TECO™ Drug Adulteration Test Strip and oxidant assay

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ashraf Mina ◽  
John Stathopoulos ◽  
Taveet Sinanian ◽  
Leah McNeice ◽  
Deirdre Holmes ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Chemical Method ◽  
Drugs Of Abuse ◽  
Test Strip ◽  
Pyridinium Chlorochromate ◽  
Chemical Methods ◽  
Ph Measurements ◽  
Validity Testing ◽  
Deming Regression ◽  
Method Agreement

Abstract Objectives In the absence of sample validity testing, a healthcare provider may fail to identify a patient’s adulteration of their urine sample. This study compared different methods for specific gravity (SG), pH, TECO™ Drug Adulteration Test Strip (dipstick) and oxidant assay to explain the differences and also make an informative decision on method selection. Methods Creatinine, SG and pH measurements are essential in sample validity testing. SG and pH automated chemical methods are compared against pH meter method, SG refractometer and dipstick method. Also, oxidant assay was compared against dipstick method. Results SG chemical method agreement with refractometer is 81.9% and with dipstick method is 64.7%. The refractometer method agreement with dipstick method is 66.1%. pH chemical method agreement with pH Meter method is 74.3% and with dipstick method is 81.4%. pH meter method agreement is 85.7% with dipstick method. Results were analysed using Deming regression analysis and F-test. SG chemical method correlated better with refractometer than the dipstick method. Oxidant assay correlated well with dipstick method in detecting adulterants such as pyridinium chlorochromate, nitrite and bleach. Conclusions Varying degrees of differences were seen in the SG and pH measurements. These differences were both method and instrument dependent. The automated chemical methods are recommended alongside oxidant assay for consistency, accuracy and faster turn-around time as part of sample validity testing for drugs of abuse.

Automated Method for the Determination of Niacin and Niacinamide in Cereal Products: Collaborative Study

1975 ◽  
Vol 58 (4) ◽  
pp. 799-803
Author(s):  
Anthony F Gross
Keyword(s):  
Chemical Method ◽  
Collaborative Study ◽  
Pet Food ◽  
Microbiological Method ◽  
Chemical Methods ◽  
Cereal Products ◽  
Automated Method ◽  
Coefficients Of Variation ◽  
Baked Products

Abstract In a collaborative study, an automated method for the determination of niacin and niacinamide in cereal products was compared with the official final action microbiological (43.121–43.125) and chemical (43.044–43.046) methods. Ten samples of cereal products, including enriched flour, yeast-leavened baked products, fortified breakfast cereals, and baked pet food products, were submitted to 14 laboratories. Nine laboratories reported values by the automated method, 6 reported values by the microbiological method, and 7 reported values by the chemical method. The results from the microbiological method were not subjected to analysis of variance because of the unusually large between-laboratory variation. The between-laboratory coefficients of variation for the automated and chemical methods were 10.90 and 10.18%, on the basis of results from 7 and 4 laboratories, respectively. There was no significant (p>0.05) difference between methods when results from the 4 laboratories who used both methods were compared. The automated chemical method has been adopted as official first action.

scholarly journals Biological and Agrotechnical Aspects of Weed Control in the Cultivation of Early Potato Cultivars under Cover

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 373
Author(s):  
Piotr Pszczółkowski ◽  
Piotr Barbaś ◽  
Barbara Sawicka ◽  
Barbara Krochmal-Marczak
Keyword(s):  
Weed Management ◽  
Chemical Method ◽  
Potato Cultivars ◽  
Mechanical Method ◽  
Third Order ◽  
Chemical Methods ◽  
Weed Infestation ◽  
Order Factor ◽  
Cultivar Assessment ◽  
Early Harvest

Problems with weed infestation under cover were the reason to conduct research on the regulation of weed infestation in potato cultivation for early harvest. The field experiment was carried out in 2015–2017 at the Experimental Station for Cultivar Assessment in Uhnin (51°34′ N, 23°02′ E) using the method of random subblocks, in a dependent system (split-split-plot). The first order factor was edible potato cultivars ‘Denar’ and ‘Lord’. The second order factor was cultivation technologies: (A) traditional technology, (B) technology using polyethylene film cover, (C) technology using polypropylene agrotextile. The third order factor was weed management methods: (1) mechanical, (2) mechanical and chemical method using Afalon Dispersion 450 SC preparation, (3) mechanical and chemical methods using Racer 250 EC herbicide, and (4) mechanical and chemical methods using a mixture of herbicides Afalon Dispersion 450 SC and Command 480 EC. Mechanical and chemical methods proved to be more effective than the mechanical method. The best effectiveness in limiting both fresh and dry weed mass in potato cultivation under cover was achieved using the mechanical and chemical method using a mixture of herbicides, Afalon Dispersion 450 SC and Command 480 EC.

scholarly journals Adulteration of Urine by “Urine Luck”

1999 ◽  
Vol 45 (7) ◽  
pp. 1051-1057 ◽  
Author(s):  
Alan HB Wu ◽  
Ben Bristol ◽  
Karen Sexton ◽  
Gina Cassella-McLane ◽  
Verena Holtman ◽  
...  
Keyword(s):  
Drug Testing ◽  
Drugs Of Abuse ◽  
Spot Test ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyridinium Chlorochromate ◽  
Urine Drug ◽  
Chain Of Custody ◽  
Drug Assays ◽  
Workplace Drug Testing

Abstract Background: In vitro adulterants are used to invalidate assays for urine drugs of abuse. The present study examined the effect of pyridinium chlorochromate (PCC) found in the product “Urine Luck”. Methods: PCC was prepared and added to positive urine controls at concentrations of 0, 10, 50, and 100 g/L. The controls were assayed for methamphetamine, benzoylecgonine (BE), codeine and morphine, tetrahydrocannabinol (THC), and phencyclidine (PCP) with the Emit II (Syva) and Abuscreen Online (Roche) immunoassays, and by gas chromatography/mass spectrometry (GC/MS). Two tests were also developed to detect PCC in urine: a spot test to detect chromate ions using 10 g/L 1,5-diphenylcarbazide as the indicator, and a GC/MS assay for pyridine. We tested 150 samples submitted for routine urinalysis, compliance, and workplace drug testing for PCC, using these assays. Results: Response rates decreased at 100 g/L PCC for all Emit II drug assays and for the Abuscreen morphine and THC assays. In contrast, the Abuscreen amphetamine assay produced apparently higher results, and no effect was seen on the results for BE or PCP. The PCC did not affect the GC/MS recovery of methamphetamine, BE, PCP, or their deuterated internal standards, but decreased GC/MS recovery of the opiates at both intermediate (50 g/L) and high (100 g/L) PCC concentrations and apparent concentrations of THC and THC-d3 at all PCC concentrations. Two of 50 samples submitted for workplace drug testing under chain-of-custody conditions were positive for PCC, whereas none of the remaining 100 specimens submitted for routine urinalysis or compliance drug testing were positive. Conclusions: PCC is an effective adulterant for urine drug testing of THC and opiates. Identification of PCC use can be accomplished with use of a spot test for the oxidant.

Determination of urine-specific gravity by means of a multiple test strip

1993 ◽  
Vol 17 (7-8) ◽  
pp. 338-342
Author(s):  
C. Franzini ◽  
D. Kutter ◽  
A. Kremer ◽  
K.-D. Willamowski
Keyword(s):  
Specific Gravity ◽  
Test Strip ◽  
Urine Specific Gravity ◽  
Multiple Test

scholarly journals Comparative Structural Studies of the Silver and Nickel Nano Composites Synthesized by Chemical Methods

2020 ◽  
Author(s):  
Giriraj Tailor ◽  
Jyoti Chaudhary ◽  
Bhupendra Kr. Sarma ◽  
Deepshikha Verma
Keyword(s):  
Metal Ions ◽  
Chemical Method ◽  
Nickel Nanoparticles ◽  
Crystallographic Structure ◽  
Structural Studies ◽  
Imaging Studies ◽  
Nickel Metal ◽  
Chemical Methods ◽  
White Spots ◽  
Particles Size Distribution

Abstract Silver and nickel nanoparticles were synthesized from urea and formaldehyde by using chemical method, followed by calcination at 8000C. The chemical composition and crystallographic structure of silver and nickel nanoparticles were confirmed by XRD. Surface imaging studies like AFM was carried out for understanding surface morphology and particles size distribution. The spherical and porous-like morphology of silver and nickel nanoparticles were confirmed by SEM and TEM. White spots are observed because of the the presence of silver and nickel metal ions in spherical forms. The particles size of silver and Nickel metal ions obtained through XRD are found to be 41.43 nm and 13.71 nm respectively.

scholarly journals Evaluation of the Clinitek 200 urinary test-strip reader in the analysis of dog and rat urines in pre-clinical toxicology studies

1993 ◽  
Vol 27 (3) ◽  
pp. 240-246 ◽  
Author(s):  
A. Paquignon ◽  
G. Tran ◽  
J. P. Provost
Keyword(s):  
Specific Gravity ◽  
Ketone Bodies ◽  
Automatic Measurement ◽  
Test Strip ◽  
Clinical Toxicology ◽  
Measurement Analysis ◽  
Low Concentrations ◽  
Test Strip Reader ◽  
Gravity Measurements ◽  
High Concentrations

The performance of a clinical urinary test-strip reader Clinitek 200 was evaluated for dog and rat urines, in the context of pre-clinical toxicology studies. No major discrepancies were found between data generated by visual estimation or automatic measurement. Analysis of spiked samples showed good agreement between actual concentrations and Clinitek 200 responses for ketone bodies and glucose although a lack of sensitivity was found for the latter. Results for proteins showed over- or underestimation in dog and rat urines respectively at low concentrations, and overestimation at high concentrations in both species. Reproducibility of responses was excellent for ketone bodies, glucose and proteins but was weaker for haemoglobin and bilirubin. High bilirubin concentrations were found to interfere with the haemoglobin reaction. The pH measurements were found to be accurate only around pH 7. Specific gravity measurements were unreliable. Overall, the Clinitek 200 as a screening tool proved sufficiently reliable in the measurement of all parameters tested, with the exception of specific gravity.

scholarly journals Genetic and chemical methods of ascertaining aflatoxigenicity give discordant results: A Case of Aspergillus species from Eastern Kenya

2021 ◽  
Author(s):  
Micah Kipkemboi Lagat ◽  
Faith Jebet Toroitich ◽  
Huxley Mae Makonde ◽  
Meshack Amos Obonyo
Keyword(s):  
Internal Transcribed Spacer ◽  
Chemical Method ◽  
Its Region ◽  
Aflatoxin Production ◽  
Toxin Production ◽  
Epigenetic Factors ◽  
Chemical Methods ◽  
Control Programs ◽  
Genetic Abundance ◽  
Maize Kernels

Abstract Background: Aflatoxins (AFs) are poisonous compounds produced by species of fungi belonging to the genus Aspergillus mainly A. flavus and A. parasiticus. However, there are some members of these species that do not produce toxins and have since become of interest for use in Biological Control programs. The species that produce AFs are believed to have clusters of aflatoxin-associated genes that confer aflatoxigenicity. However, recent findings suggest that the presence of aflatoxin genes may not imply aflatoxin production capability. We therefore examined the extent to which the presence or absence of aflatoxin-associated genes (genetic) infers aflatoxigenicity using the Dichlorvos-Ammonia (chemical) method as reference.Results: We report a dissonance between the genetic and chemical methods of ascertaining aflatoxigenicity. Fungi (n = 314) that were morphologically identified as A. flavus and A. parasiticus were isolated from maize kernels and soil from Eastern Kenya. The fungi were further characterized to confirm their identities using a PCR-sequence analysis of the internal transcribed spacer (ITS) region of rDNA which confirmed them to be Aspergillus species. We selected and induced 16 isolates in YES media amended with Dichlorvos to produce AFs. Seven of the sixteen isolates were DM-AM positive (aflatoxigenic) but lacked at least one of the key aflatoxin-associated genes. Even more confounding, A. flavus isolate (1EM2606) had all aflatoxin-associated genes but was non-aflatoxigenic (DV-AM negative) while A. flavus (1EM1901) having all genes was aflatoxigenic (DV-AM positive). The genetic abundance of the AF-asscociated genes among the isolates was as follows: aflQ (100%), aflD (62.5%) followed by aflR (37.5%) and aflP (25%). Conclusion: We report that either method alone is limited in ascertaining aflatoxigenicity among Aspergillus section Flavi. The discordance between presence of aflatoxin-associated genes and aflatoxigenicity may be due to epigenetic factors that affect secondary metabolism, or even other signaling processes that alter toxin production that still remain poorly understood.

Further evaluation of a specific-gravity test strip.

1983 ◽  
Vol 29 (8) ◽  
pp. 1551-1551 ◽  
Author(s):  
S Winsten ◽  
S E Gordesky ◽  
E M Riggs
Keyword(s):  
Specific Gravity ◽  
Test Strip ◽  
Gravity Test
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