Neal Craft

The National Institute of Standards and Technology (NIST) has prepared and certified SRM 1507, a freeze-dried urine fortified with 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (THC-9-COOH), the major urinary metabolite of marijuana. The certified concentration of 20 +/- 1 ng/mL for the analyte was obtained from the concordant results of analyses of the material by gas chromatography/mass spectrometry (GC/MS) and high-performance liquid chromatography with electrochemical detection (HPLC-EC). Solid-phase extraction was used to prepare the sample for GC/MS analyses, and liquid-liquid extraction was used for the HPLC-EC analyses. The multistep HPLC method was developed at NIST to circumvent interferences from urinary constituents. The results of a round robin test on this material among five Department of Defense laboratories involved in drug testing are reported.

We describe an improved method for the measurement of retinol in dried blood spots (DBS) on filter paper. Retinol in human DBS on filter paper was analyzed by normal phase HPLC after a simple extraction method. Retinol associated with its binding protein was eluted from the paper into aqueous solution facilitated by ultrasonic agitation. Retinol associated with retinol binding protein was denatured with acetonitrile, and then retinol was isolated in a single hexane extract and analyzed directly by HPLC. When analyzing DBS, the individual plasma volume of the spots was calculated by measuring the sodium content or by weighing the blood spots. The described method yielded low intra- and interassay variability (<6%), with sufficient sensitivity (detection limit, 0.1 micromol/L) and good recovery (97% spike). Compared with matching plasma samples, DBS retinol consistently decreased 18-23% during the 1st wk of storage. After 1 wk, retinol remained stable in the blood spots at 23 degre...

We have developed a high-performance capillary electrophoresis (HPCE) method to analyze the retinol (vitamin A) concentration as retinol-retinol binding protein (holo-RBP) from microvolumes of serum (5-10 microliters) or one to two drops (approximately 20 microliters) of blood collected and air-dried on blood collection filter paper. A 0.64-cm diameter disk was cut from the dried whole blood specimens and the samples were dissolved in a pretreatment buffer and filtered. Filtrate was injected onto the HPCE column for analysis. The separation was carried out in a 60 cm x 50 microns I.D. fused-silica capillary and the running voltage was 20 kV. A He-Cd laser with a wavelength of 325 nm was used for excitation, and the fluorescence of the holo-RBP complex was monitored at 465 nm by a photodiode. A virtual linear relationship was obtained for the retinol concentrations between HPCE and HPLC for 28 serum samples, 19 dried venous blood samples and 9 capillary dried blood spot samples, indi...

Retinoids (natural and synthetic derivatives of vitamin A) have cancer chemotherapeutic and chemopreventive activities. Retinoic acid (RA) treatment has been associated with significant regression of preneoplastic lesions. However, serious toxicity associated with some therapies has made long-term chemoprevention in healthy populations unfeasible. Recently, serum RA has been shown to increase in response to oral retinol (vitamin A) supplementation. Here, we assess the variability of circulating RA levels and the lifestyle, demographic, and nutritional factors that explain such variability. Total RA concentration and the concentrations of RA isomers (all-trans-RA, 13-cis-RA, and 9-cis-RA) were measured by high-pressure liquid chromatography in serum samples obtained 4 months apart from 502 women participating in the Ludwig-McGill Cohort (Sao Paulo, Brazil). The relative abundance of the three RA isomers was similar for each visit (baseline and month 4), with 13-cis-RA having the high...

The specific cause of short stature in juvenile rheumatoid arthritis (JRA) is unknown. One hypothesis links altered growth to inadequate dietary intake. In this study, nutritional status was assessed in 34 children with JRA (8 with systemic JRA, 14 with polyarticular JRA, and 12 with pauciarticular JRA) and 9 healthy controls using 3-day diet records, anthropometrics, and biochemical analyses. Differences in growth were found among the three types of JRA. One third of all subjects were at or below the 10th percentile in height for age (these being predominantly among the systemic and polyarticular groups). With few exceptions, the mean dietary intake for calories and essential nutrients was found to be adequate for each of the three groups. However, more than half of those with systemic JRA reportedly consumed less than the recommended caloric intake for their age and weight. No significant correlations were found linking dietary intake to growth percentiles in any of the groups studied. Biochemical abnormalities were found among the systemic and polyarticular groups. These abnormalities included low plasma levels of vitamins A and C, proteins (albumin, prealbumin, and retinol binding protein) and zinc; and increased levels of copper and glutathione peroxidase activity. Plasma selenium and vitamin E levels were unchanged. The discrepancy between intake and certain circulating nutrient levels may reflect alterations in the requirements, absorption, or use of these nutrients in the presence of chronic inflammation.

The consumption of tomato products is associated with a reduced risk of cardiovascular disease and several cancers. It is hypothesized that lycopene, the major carotenoid in tomato products, may mediate this relationship. We designed a study to examine changes in plasma and buccal mucosal cell (BMC) lycopene concentrations in healthy adults consuming standard daily servings of processed tomato products: spaghetti sauce, tomato soup, or vegetable juice. Thirty-six healthy subjects consumed a lycopene-free diet for 2 wk and were then assigned to one of three (n = 12) intervention groups consuming daily, single servings of sauce (21 mg lycopene per (1/2) cup), soup (12 mg lycopene per 1 cup), or juice (17 mg lycopene per 8 oz) for 4 wk. Fasting blood and BMC samples were evaluated by high-performance liquid chromatography analysis for carotenoids and lycopene isomers. Total plasma lycopene concentrations (Mean +/- SEM) decreased from 1.05 +/- 0.07 to 0.54 +/- 0.05 micromol/l (49%, P < 0.0001) during the 2-wk washout period. Following intervention, plasma lycopene concentrations increased significantly for those consuming sauce, soup, and juice (compared with washout baseline) to 2.08 (192%, P < 0.0001), 0.91 (122%, P < 0.0001), and 0.99 (92%, P < 0.0001) micromol/l, respectively. Plasma isomer concentrations show a 61:39 ratio of cis:all-trans at the start of the study. During the 2-wk washout the decrease in plasma all-trans-lycopene was greater than that for pooled cis isomers (70:30 cis:trans ratio, P < 0.001). After 2 wk of dietary intervention isomer ratios returned to those observed at the start of the study. Total BMC lycopene concentrations did not significantly change during the brief washout. During the 4-wk intervention period, BMC total lycopene concentrations increased (P < 0.005) by 165, 42, and 48% nmol/mg protein for those consuming sauce, soup, and juice, respectively. This study demonstrates that plasma lycopene decreases by 50% after approximately 2 wk on a lycopene-free diet with a decrease in the ratio of all-trans compared with cis isomers. Single, daily servings of processed tomato products significantly increase blood and BMC lycopene for 2 wk. Additional studies of lycopene bioavailability, isomerization, metabolism, and bioactivity will provide greater insight into the potential health benefits suggested by epidemiological studies and laboratory investigations.

... bi-ological matrices, and neat solutions has been demonstrated (Bushway 1985, MacCrehan and Schönberger 1987, Quackenbush 1987, Craft 1990, Craft et al. ... between chlo-rophyllide a and chlorophyll cs, however, can be RaU-lut = 1-4 ZER a-CHR ß-CRR NEO С 1 Fig. ...

To determine the performance of a portable fluorometer for measuring serum retinol (SR) concentration. Serum samples were obtained from 75 factory worker women and 143 school children. SR concentration was quantified using a portable fluorometer ('CRAFTi') and HPLC analysis. SR by HPLC (1.23 ± 0.43 μmol/L) and CRAFTi (1.16 ± 0.46 μmol/L) was significantly correlated. Sensitivity and specificity were 85.3% and 78.0% (cutoff of 1.05 μmol/L). Kappa statistics showed moderate agreement. CRAFTi portable fluorometer is a promising field-friendly tool for screening vitamin A deficiency.

A variety of bonded phase parameters (endcapping, phase chemistry, ligand length, and substrate parameters) were studied for their effect on column retention and selectivity toward carotenoids. Decisions were made on how each of these variables should be optimized based on the separation of carotenoid and polycyclic aromatic hydrocarbon test probes. A column was designed with the following properties: high absolute retention, enhanced shape recognition of structured solutes, and moderate silanol activity. These qualities were achieved by triacontyl (C30) polymeric surface modification of a moderate pore size (approximately 20 nm), moderate surface area (approximately 200 m2/g) silica, without subsequent endcapping. The effectiveness of this "carotenoid phase" was demonstrated for the separation of a mixture of structurally similar carotenoid standards, an extract of a food matrix Standard Reference Material, and a beta-carotene dietary supplement under consideration as an agent for cancer intervention/prevention.

... Liquid chromatographic method for the determination of patulin in apple juice using solid-phase extraction. ... The most of analytical methods consist of multiple liquid–liquid partition steps for the extraction of patulin in apple juice. ...

Mislabeling of farmed and wild salmon sold in markets has been reported. Since the fatty acid content of fish may influence human health and thus consumer behavior, a simplified method to identify wild and farmed salmon is necessary. Several studies have demonstrated differences in lipid profiles between farmed and wild salmon but no data exists validating these differences with government-approved methods to accurately identify the origin of these fish. Current methods are both expensive and complicated, using highly specialized equipment not commonly available. Therefore, we developed a testing protocol using gas chromatography (GC), to determine the origin of salmon using fatty acid profiles. We also compared the GC method with the currently approved FDA (United States Food and Drug Administration) technique that uses analysis of carotenoid optical isomers and found 100% agreement. Statistical validation (n = 30) was obtained showing elevated 18:2n-6 (z = 4.56; P = 0.0001) and decreased 20:1n-9 (z = 1.79; P = 0.07) in farmed samples. The method is suitable for wide adaptation because fatty acid methyl ester analysis is a well-established procedure in labs that conduct analysis of lipid composition and food constituents. GC analysis for determining the origin of North American salmon compared favorably with the astaxanthin isomer technique used by the FDA and showed that the fatty acid 18:2n-6 was the key indicator associated with the origin of these salmon.