High Resolution GC-MS Research Articles

Water‐soluble omega‐3: A concept for purification of fish oil and nutraceuticals?

AbstractThere is a need for improved processes for preparation of omega‐3 PUFA formulations having a high content of PUFA, low levels of persistent environmental pollutants (EPs), acceptable oxidation stability and if possible, can be formulated as a powder. Using N‐methyl glucamine (meglumine), which forms water‐soluble omega‐3 salts, an extraction process was developed that for the first time removed the EPs present in the starting material (commercially available cod liver oil added fish oil, CLO‐FO). GC/high‐resolution MS (GC‐HRMS) showed levels of three common EPs that were below LOQ. Further, the fatty acid salts isolated were enriched in omega‐3 and appeared as water‐soluble white powders. The overall process increased the content of omega‐3 by >70% compared with CLO‐FO. The content of saturated fatty acids was reduced from 12.8 ± 0.6 to 2.1 ± 0.1%. In spite of using inert conditions during preparation, the oxidative deterioration was significant. When this issue is resolved, the powder may be further developed for use in tablets or other nutritional and health products.See accompanying commentary by Destaillats [1293–1295]

PCBs/Hydroxylated PCBs Exposure and Thyroid Function of Japanese Pregnant Women: Preliminary Result From a Cohort Study

PP-31-133 Background/Aims: Thyroid hormone is essential for fetal brain development. It is particularly so during the first trimester of pregnancy when fetus is dependent on maternal thyroid hormone supply. Recent studies indicate that environmental chemicals can interfere with thyroid hormone function. We are planning a prospective cohort study to examine the association between maternal exposure to chemicals, thyroid hormone status and development of offspring. The aim of the present study is to examine the relationship between exposure to PCBs and their hydroxylated metabolites (OH-PCBs) and thyroid hormone status in Japanese women during the first trimester of pregnancy. Methods: We enroll pregnant women of 10–12 gestational weeks at a hospital in Tokyo after obtaining informed consent. Blood and urine are sampled at the enrollment and we analyze PCBs and OH-PCBs in serum by high resolution-GCMS, thyroid hormone status (free T4, TSH, TBG), and urinary iodine. Results: The concentrations of PCBs and OH-PCBs in serum were not excessive level (ΣPCBs: 190–1200 pg/g wet weight; sum of OH-PCB congeners (Cl5–7): 35–360 pg/g wet weight) in the present subjects. At present, we found positive association between concentrations of some of the PCB/OH-PCB congeners and thyroid hormone status. As expected, urinary iodine concentration was high with a large inter-individual variation (72.1–1720 μg/g creatinine) and a statistically significant inverse relationship was found between the concentrations of urinary iodine and the concentrations of free T4 in serum (r = −0.605, P < 0.05, n = 17). Conclusion: Our results suggest that exposure to some PCB/OH-PCB congeners has association with free T4 level in pregnant women and also that excessive iodine intake may adversely affect thyroid hormone status in Japanese.

Pyrrolizidine alkaloids in pollen and pollen products

Recently, 1,2-dehydropyrrolizidine alkaloid (PA) ester alkaloids, found predominantly as their N-oxides (PANOs, pyrrolizidine N-oxides), have been reported in both honey and in pollen obtained directly from PA plants and pollen loads collected by bees, raising the possibility of health risks for consumers of these products. We confirm these findings in regard to floral pollen, using pollen collected directly from flowers of the known PA plants Senecio jacobaea, S. vernalis, Echium vulgare and pollinia of Phalaenopsis hybrids, and we extend analyses of 1,2-unsaturated PAs and 1,2-unsaturated PANOs to include bee-pollen products currently being sold in supermarkets and on the Internet as food supplements. PA content of floral pollen ranged from 0.5 to 5 mg/g. The highest values were observed in pollen obtained from Senecio species. Up to 95% of the PAs are found as PANOs. Detailed studies with S. vernalis revealed unique PA patterns in pollen and flowers. While seneciphylline was the most prominent PA in S. vernalis pollen, the flowers were dominated by senecionine. To analyze trace amounts of 1,2-unsaturated PAs in pollen products, our previously elaborated method consisting of strong cation exchange-SPE, two reduction steps followed by silylation and subsequent capillary high-resolution GC-MS using SIM mode was applied. In total, 55 commercially available pollen products were analyzed. Seventeen (31%) samples contained 1,2-unsaturated PAs in the range from 1.08 to 16.35 microg/g, calculated as retronecine equivalents. The 1,2-unsaturated PA content of pollen products is expressed in terms of a single sum parameter and no background information such as foraged plants, pollen analysis, etc. was needed to analyze the samples. The detection limit of overall procedure and the reliable quantitation limit were 0.003 and 0.01 microg/g, respectively.

Application of mass spectrometry in the analysis of polybrominated diphenyl ethers

This review summarized the applications of mass spectrometric techniques for the analysis of the important flame retardants polybrominated diphenyl ethers (PBDEs) to understand the environmental sources, fate and toxicity of PBDEs that were briefly discussed to give a general idea for the need of analytical methodologies. Specific performance of various mass spectrometers hyphenated with, for example, gas chromatograph, liquid chromatograph, and inductively coupled plasma (GC/MS, LC/MS, and ICP/MS, respectively) for the analysis of PBDEs was compared with an objective to present the information on the evolution of MS techniques for determining PBDEs in environmental and human samples. GC/electron capture negative ionization quadrupole MS (GC/NCI qMS), GC/high resolution MS (GC/HRMS) and GC ion trap MS (GC/ITMS) are most commonly used MS techniques for the determination of PBDEs. New analytical technologies such as fast tandem GC/MS and LC/MS become available to improve analyses of higher PBDEs. The development and application of the tandem MS techniques have helped to understand environmental fate and transformations of PBDEs of which abiotic and biotic degradation of decaBDE is thought to be one major source of Br(1-9)BDEs present in the environment in addition to direct loading from commercial mixtures. MS-based proteomics will offer an insight into the molecular mechanisms of toxicity and potential developmental and neurotoxicity of PBDEs.

Serum concentration of 27‐hydroxycholesterol predicts the effects of high‐cholesterol diet on plasma LDL cholesterol level

The effect of dietary cholesterol on plasma cholesterol concentrations varies widely among individuals. Recent studies suggest that the synthesis of oxysterols is up-regulated when tissue cholesterol is saturated. The present study was undertaken to test the hypothesis that a serum high concentration of 27-hydroxycholesterol, one of the oxysterols, reflects positive cholesterol balance in the body and predicts intolerance to a high-cholesterol diet. In 30 subjects, 750 mg/day of cholesterol was added for 4 weeks to the ordinary diet. Blood samples were collected at the start and finish of the supplementation. Serum sterol and oxysterol concentrations were measured by high-resolution GC-MS. A receiver operating characteristic curve was drawn and the cutoff point (80 ng/mg cholesterol) was chosen to maximize sensitivity (81.3%) and specificity (64.3%) for predicting a positive change of LDL cholesterol concentration after cholesterol loading. Subjects with higher serum 27-hydroxycholesterol concentrations (>/= 80 ng/mg cholesterol) showed significantly (P < 0.05) high values for the change of LDL cholesterol concentration (+7.4 +/- 3.4%, mean +/- SEM, n = 17) compared with those with lower 27-hydroxycholesterol levels (-5.3 +/- 2.7%, n = 13). In subjects with high serum 27-hydroxycholesterol concentrations were unable to adapt to a high-cholesterol diet. The concentration of serum 27-hydroxycholesterol appears to reflect cholesterol saturation in the body and predicts to some extent a responsiveness to dietary cholesterol.

Volatile Constituents from the Leaves and Flowers of Murraya koenigii (Linn.) Spreng

The volatiles of fresh leaf and flower of Murraya koenigii,grown in Thiruvananthapuram, Kerala were isolated by simultaneous distillation and extraction method and analysed by high resolution GC and GC-MS. Fifty two constituents were identified in the leaf oil, comprising 98.45 % of the volatiles. The major components were monoterpene hydrocarbons (19.67 %) and sesquiterpene hydrocarbons (72.96 %) of which β-caryophyllene (45.92 %) is the major one followed by β-bisabolene (9.79 %), γ-muurolene (9.075 %), eudesmane (5.33 %), α-pinene (6.04 %) and limonene (8.53 %). In the flower oil, 50 components were identified, constituting 90.66 % of the volatile oil. Here too, the major constituents were monoterpene hydrocarbons (60.67 %) and sesquiterpene hydrocarbons (11.99 %), and Limonene (37.17 %) and camphene (14.87 %) are the major constituents. Apart from this the flower oil contains quite number of alcohols and esters compared to that of leaf oil.

Disposition of Bromodichloromethane in Humans Following Oral and Dermal Exposure

Exposure to bromodichloromethane (BDCM), one of the most prevalent disinfection byproducts in drinking water, can occur via ingestion of water and by dermal absorption and inhalation during activities such as bathing and showering. The objectives of this research were to assess BDCM pharmacokinetics in human volunteers exposed percutaneously and orally to (13)C-BDCM and to evaluate factors that could affect disposition of BDCM. Among study subjects, CYP2E1 activity varied fourfold; 20% had the glutathione S-transferase theta 1-1 homozygous null genotype; and body fat ranged from 7 to 22%. Subjects were exposed to (13)C-BDCM in water (target concentration of 36 mug/l) via ingestion and by forearm submersion. Blood was collected for up to 24 h and analyzed for (13)C-BDCM by solid-phase microextraction and high-resolution GC-MS. Urine was collected before and after exposure for mutagenicity determinations in Salmonella. After ingestion (mean dose = 146 ng/kg), blood (13)C-BDCM concentrations peaked and declined rapidly, returning to levels near or below the limit of detection (LOD) within 4 h. The T(max) for the oral exposure ranged from 5 to 30 min, and the C(max) ranged from 0.4 to 4.1 ng/l. After the 1 h dermal exposure (estimated mean dose = 155 ng/kg), blood concentrations of (13)C-BDCM ranged from 39 to 170 ng/l and decreased to levels near or below the LOD by 24 h. Peak postdose urine mutagenicity levels that were at least twice that of the predose mean level occurred in 6 of 10 percutaneously exposed subjects and 3 of 8 orally exposed subjects. These results demonstrate a highly significant contribution of dermal absorption to circulating levels of BDCM and confirm the much lower oral contribution, indicating that water uses involving dermal contact can lead to much greater systemic BDCM doses than water ingestion. These data will facilitate development and validation of physiologically based pharmacokinetic models for BDCM in humans.

Progress in understanding the N-demethylation of alkaloids by exploiting isotopic techniques

The reaction of N-demethylation plays an important role in the degradation of some alkaloids in a number of organisms. This review presents how our understanding of the N-demethylation of nicotine in plants has been improved through studies in cell cultures of Nicotiana plumbaginifolia and N. glutinosa using a variety of isotopic techniques. The overall aim is to understand how metabolism recycles the alkaloid skeleton, both in terms of the metabolic route(s) exploited and the reaction mechanisms of the enzymes involved. The former has been approached using high-resolution 2-dimensional NMR and GC-MS methods; the latter by determining kinetic isotope effects and modelling the potential reaction steps. It appears that the mechanism for nicotine demethylation in plants is similar to but has significant differences from that described for mammals and Pseudomonas bacteria. These differences are discussed.

On the prenylation of some indolic and imidazolic bases by oxirane auxiliaries under thermal and microwave conditions

The analogue of isoprene, 2-methyl-2-vinyloxirane, a versatile isoprene auxiliary, was reacted with some indolic and imidazolic bases, to add one or more isoprene unit(s), to these compounds. This prenylation was realised by using thermal and microwave assisted pathways, via the nucleophilic opening of the epoxide ring. The biological importance of the prenylated derivatives resides in their potential application as drugs. The aminoacids and small protein biomarkers are obtained from simple epoxide opening reactions. All new compounds were characterised by high resolution NMR, mass spectroscopy, GC-MS and LC-MS as well.

Composition of North Indian Pyrethrum (Chrysanthemum cinerariaefolium) Flower Oil

The hydrodistilled oil obtained from the dried pyrethrum flowers (Chrysanthemum cinerariaefolium) was subjected to high resolution GC and GC-MS, leading to the quantification and identification of twenty two compounds representing (85.27%) of the total oil. trans-chrysanthemumic acid (19.61%), decanoic acid (7.63%), nerolidol (9.63%), spathulenol (4.58%), guaiol (5.93%), β-eudesmol (9.81%) and α-eudesmol (7.07%) were the major compounds. The oil of Indian species is uniquely different from the oil obtained from pyrethrum of Kenya’s origin.

Bioavailability and mass balance studies of a commercial pentabromodiphenyl ether mixture in male Sprague–Dawley rats

Polybrominated diphenyl ethers (PBDE) are common flame retardants used in polyurethane foam, high impact polystyrene, and textiles which appear to be increasing in the environment and biota. Two PBDE congeners that are particularly prominent in environmental samples are 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) and 2,2′,4,4′,5-pentabromodiphenyl ether (BDE-99). These two congeners are major components in penta-BDE formulations which constitute a minor percentage of the commercial PBDE market. In order to determine the bioavailability and bioconcentration potential of these PBDEs, we have conducted a feeding experiment in rats, dosing with low amounts of a commercial penta-BDE mixture for 21 days to mimic an environmental exposure. The carcasses, livers, and feces from control and dosed rats were quantitated for PBDEs by a high resolution GC–MS isotope dilution method. Between 25% and 50% of each of the dosed congeners was retained in the rats with the liver being a minor depot (<1% of the dose). Fecal excretion accounted for 4–12% of the dosed congeners. A large percent of the dose (40–60%) was not recovered indicating that metabolic transformations may have occurred in the rats. Hydroxylated metabolites were qualitatively identified in the feces and carcass by GC–MS. The relative congener distribution in each tissue was nearly identical to the congener distribution of the commercial mixture. Conclusions from the study suggest that the tetra- to hexa-BDEs present in commercial penta-BDE formulations are largely bioavailable, that bioavailability in the rat is not dependent on the degree of bromination, and that metabolism may occur to a large extent during a chronic exposure.

Estimating mutagenic compounds generated during photolysis of fenitrothion—by HPLC fractionation followed by mutagenicity testing and high-resolution GC–MS analysis

We aimed to: (1) evaluate the change in mutagenicity of a fenitrothion-containing solution during photolysis and (2) elucidate mutagenic compounds that were possible major contributors to mutagenicity. A batch test involving irradiation by natural sunlight was conducted on the solution, and then HPLC fractionation, mutagenicity testing, and gas chromatography–mass spectrometry (GC–MS) analysis were performed on the irradiated solution. During the 15-day photolysis, fenitrothion was almost completely decomposed, and 34 transformed products (TPs) were generated. Photolysis decreased the mutagenicity of the fenitrothion-containing solution for base-pair-substitution-detecting tester strains (YG1026 and YG1029) but increased mutagenicity for frameshift-detecting tester strains (YG1021 and YG1024). One TP was identified as a potential source of the increased mutagenicity; its molecular formula was estimated to be (CH 3O) 2PS–O–C 8H 6NO.

Risk assessment of di(2-ethylhexyl)phthalate released from PVC blood circuits during hemodialysis and pump–oxygenation therapy

This study deals with in vitro investigation of the release of di(2-ethylhexyl)phthalate (DEHP) during hemodialysis and pump–oxygenation therapy using medical grade PVC tubing. High resolution GC–MS analysis showed that the release of DEHP was time-dependently increased by circulation of bovine blood into a major system for the hemodialysis that is used in Japan, and the amount of DEHP released into the blood had reached 7.3 mg by 4 h of circulation. No significant difference was observed in the release patterns of DEHP under the conditions with and without fluid removal treatment during hemodialysis, indicating that the treatment seems not to be effective for eliminating DEHP from the blood through the hemodialysis membrane. Mono(2-ethylhexyl)phthalate (MEHP) analysis revealed that a small amount of DEHP (3–4%) was converted to MEHP by hydrolysis during the circulation of blood. A considerable amount of DEHP was also released from the PVC circuit mimicking the pump–oxygenation system, and 7.5–12.1 mg of DEHP had migrated into bovine blood from the circuit by 6 h. It was noticed, however, that the release was obviously suppressed by covalently coating the inner surface of the PVC tubing with heparin, though this effect was not observed with ionic bond type-heparin coating. Covalent bond type-heparin coating of PVC tubing seems to offer the advantage of decreasing the amount of DEHP exposure to patients during treatment using a PVC circuit.

Degradation profiles of branched nonylphenol isomers by Sphingobium amiense and Sphingomonas cloacae

Biodegradation activity of branched nonylphenols (BNPs) by Sphingobium amiense strain YTT and Sphingomonas cloacae strain S-3T was examined. High-resolution GC-MS was used to separate five isomer groups from the commercial BNP mixture. In the time course experiments of BNP degradation, the isomers with alpha-dimethyl and those with α-methyl, α-ethyl configurations were rapidly degraded by Sphingobium amiense strain YTT, while those with highly branched chains were broken down less efficiently. In contrast, Sphingomonas cloacae strain S-3T degraded all the isomers of the BNP groups at similar rates. The utilization and degradation of 4-n-alkylphenols (C3 to C9) and 8 phenolic acids were also tested with the strains. The results suggested that Sphingomonas cloacae strain S-3T displays a catabolic activity possesses the catabolism specific of branched alkylphenols, while Sphingobium amiense strain YTT is a versatile organism capable of utilizing a wide range of phenolic compounds including phenolic acids, and of degrading 4-n-alkylphenols and a limited range of BNPs.

Regional distribution of PCBs and presence of technical PCB mixtures in sediments from Norwegian and Russian Arctic Lakes

The results of measurement of polychlorinated biphenyls (10 PCB congeners recommended by AMAP) in surface bottom sediments collected from 26 remote lakes in Northern Norway and 11 lakes in North Russia in 1994 and 1995 are presented. Cores were collected from the deepest part of each lake with a gravity corer. The north Russian lakes were shallow ponds less than 1 m deep, while the north Norwegian lakes and the lakes on the Svalbard Archipelago were usually 10–30 m deep. The sediment samples were analyzed by GC-high resolution MS analyses. The range of concentrations was wide. In sediment from the tundra ponds, ∑PCB were generally low, ranging from 0.2 to 1.4 ng/g dry weight (dw), with one exception (19.3 ng/g dw). In sediments from the north Norwegian lakes and the lakes on Svalbard Archipelago, the concentration was ranging from 0.7 to 35.4 ng/g dw. The geographical distribution and possibility of geographic gradients of the ∑PCB is discussed. The PCB composition is further analyzed by statistical methods to indicate possible presence and contribution of 10 various technical PCB mixtures (Chlorphens, Kanechlors, Arochlors, Sovols) in the samples.

Determination of degradation products and pathways of mancozeb and ethylenethiourea (ETU) in solutions due to ozone and chlorine dioxide treatments.

The objective of the present study was to determine the degradation products of mancozeb and ethylenethiourea (ETU) and elucidate the possible degradation pathways in solution as a result of chemical oxidation using ozone and chlorine dioxide. This study was developed in a solution at 100 ppm of mancozeb and ETU concentration over the course of 60 min. Two different oxidizing agents used in this study were (1) ozone at 3 ppm and (2) chlorine dioxide at 20 ppm. Ozone was continuously provided throughout the course of the reaction. Degradation products were detected with high-resolution GC-MS. The total analysis time was 4 min per sample combined with rapid GC separation and time-of-flight mass spectrometry (TOFMS). Hydrolysis of mancozeb led to m/z 144 ion fragmentation, which is 5-imidazoledithiocarboxylic acid, as a major degradation product. ETU showed M(+) 102, which corresponds to its mass, indicating this compound was stable in distilled water and did not undergo hydrolysis during 60 min. The average retention times of mancozeb and ETU were approximately 181-189 and 210-230 s, respectively. Ozonation of mancozeb produced ETU as a major product. Treatment of ETU with ozone produced several degradation compounds. From prolonged ozonation, the CS(2) or CS group was removed. Overall, several byproducts identified were M(+) 60, M(+) 84, M(+) 163, M(+) 117, and M(+) 267 by ozone and M(+) 117, M(+) 86, and M(+) 163 by chlorine dioxide treatment. Several of these have been reported, but others have never been reported previously.

Observation of volatile and semi-volatile carbonyls in an Algerian urban environment using dinitrophenylhydrazine/silica-HPLC and pentafluorophenylhydrazine/silica-GC-MS.

Lower carbonyls and n-alkanals from C5 to C10 were measured from late autumn 2000 to summer 2001 in two urban areas in the Algerian territory: Algiers and Ouargla. They were collected on silica cartridges coated with dinitrophenylhydrazine (DNPH) and pentafluorophenylhydrazine (PFPH), which were analysed by HPLC-UV and high-resolution GC-MS. respectively. The two methods were used in parallel samplings in a suburban Algiers site and provided consistent results for semi-volatile congeners, as differences in the concentration data did not exceed 21% on average for individual carbonyl levels ranging from 0.0 to 0.5-2.6 microg m(-3). Concentrations of formaldehyde up to 27 and 5 microg m(-3) were monitored during 10 h samplings in the daytime in Algiers and Ouargla, respectively; acetaldehyde reached values of 13 and 5 microg m(-3), whilst acetone was the most abundant ketone with peak levels of 14 and 4 microg m(-3), respectively. High night-time levels of lower carbonyls were also measured at both locations. Among the semi-volatile alkanals, the highest levels were observed in suburban Algiers for hexanal and nonanal (2.2 microg m(-3)) and in downtown Algiers for valeraldehyde (2.6 microg m(-3)), whilst in Ouargla only hexanal and nonanal levels within the C5-C10 fraction exceeded 1 microg m(-3). Moreover, benzaldehyde concentrations as high as 5 microg m(-3) were measured in the centre of Algiers. Algiers data are comparable with those found in photochemically polluted urban areas of Europe and the USA. Strong correlations between formaldehyde and acetaldehyde and between formaldehyde and benzaldehyde were observed; by contrast, acetone did not show any correlation with the lower aldehydes, suggesting the existence of carbonyl sources other than vehicular traffic. Diurnal variations of almost all carbonyls suggested that motor vehicles were the most important source in the winter, whereas photochemical production appeared to predominate during the summer.

Occurrence of p-nonylphenol isomers in wild species of Cichorium endivia subsp. divaricatum.

p-Nonylphenol isomers and other aromatic compounds were found in roots and stalks of the plant Cichorium endivia subsp. divaricatum. These compounds were characterized by high-resolution capillary GC-MS.

Fast clean-up for polychlorinated dibenzo- p-dioxins, dibenzofurans and coplanar polychlorinated biphenyls analysis of high-fat-content biological samples

A fast clean-up procedure for the low level analysis of polychlorinated dibenzo- p-dioxins, polychlorinated dibenzofurans and coplanar polychlorinated biphenyls in highly fatty biological matrices using high capacity disposable multi-layer silica columns is presented. Results were compared with gel permeation chromatography for removal of lipids. Analytical criteria such as recovery rates, repeatability, reproducibility and robustness are evaluated through a broad range of biological matrices and reference materials analysis. The final proposed procedure for the complete analysis, including pressurized liquid extraction, Power-Prep system clean-up and GC–high-resolution MS analysis requires only 48 h, and allows the simultaneous preparation of up to 10 samples.

Environmental Screening of Acidic Compounds Based on Capillary Zone Electrophoresis/Laser-Induced Fluorescence Detection with Identification by Gas Chromatography/Mass Spectrometry and Gas Chromatography/High-Resolution Mass Spectrometry

This paper describes the application of capillary zone electrophoresis/laser-induced fluorescence detection (CZE/LIF) to the discovery of acidic compounds in environmental matrixes or the screening of extracts for acidic components. Published studies indicate that coal-derived materials contain a significant fraction of acidic compounds relative to materials derived from petroleum and shales. Such compounds may be useful as marker compounds for site assessment and source apportionment issues, and their identification may be important in toxicological and other health issues. We used deep-UV light from the frequency-doubled Ar ion laser at 244 and 257 nm to study extracts of samples. The CZE/LIF technique possesses good sensitivity and therefore overcomes one of the limitations of CZE with UV detection. The present work depends on high pressure/temperature solvent extraction of polynuclear aromatic hydrocarbon (PNA)-contaminated soil, followed by separation using CZE. The anionic analytes were separated by using borate or phosphate buffer (pH 9.2-12.3) after a chemical class separation. Samples were also characterized by gas chromatography/mass spectrometry (GC/MS) using full scans at low resolution, and elemental compositions were determined unequivocally by GC/high-resolution MS (GC/HRMS) using mass peak profiling (MPP). The similarity of low-resolution electron ionization mass spectra for a standard, 1-hydroxypyrene, and for a series of compounds in a contaminated-soil extract suggested that several types of phenolic and hydroxy-PNAs were present, including hydroxylated derivatives of fluorenes, fluoranthenes, and pyrenes. GC/HRMS using MPP confirmed the elemental compositions of the hydroxyfluorenes and hydroxypyrenes (and presumably hydroxyfluoranthenes) as [C13H10O] and [C16H10O], respectively. A new version of the MPP software was written for the Finnigan-MAT 900S-Trap and was similar to that developed previously for the VG 250SE. Inclusion of a calibration ion in addition to a lock mass ion in the multiple-ion detection descriptor provided errors of <1 ppm for the 3 partial profiles of the analytes. A mass resolution of 31,000 was used to resolve the analyte signals from interferences evident in the full M+1 and M+2 profiles in the case of the hydroxyfluorenes. Derivatization was also performed to form the tert-butyldimethylsilyl derivatives of phenolic hydroxy groups as a further confirmation of structure.