ObjectiveTo analyze the exposure-response relationship of peripheral whole blood chromium level and lung function as well as genetic toxicity indicators in workers exposed to hexavalent chromium [Cr(Ⅵ)] compounds, and to propose a biological exposure limit of whole blood chromium for soluble Cr(Ⅵ) compounds-exposed workers. Methods A total of 515 workers from a dynamic occupational Cr(Ⅵ) compounds-exposed cohort in an enterprise from 2010 to 2017 were selected as the research subjects using a retrospective cohort study. A total of 918 followed-up results of research subjects and baseline data of a cohort were analyzed based on bibliometric analysis. The results include lung function tests, whole blood chromium level detected by inductively coupled plasma-mass spectrometry, urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) detected by high performance liquid chromatography-tandem mass spectrometry, peripheral micronuclei frequency (MNF) detected by cytokinesis-block micronucleus assay, and mitochondrial DNA copy number (mtCN) detected by real-time fluorescence quantitative polymerase chain reaction. Results The results of bibliometric analysis showed that domestic and foreign studies on biological monitoring of Cr(Ⅵ) compounds increased year by year in the past 30 years, and whole blood chromium levels had a good correlation with the occupational Cr(Ⅵ) compounds exposure. The geometric mean of whole blood chromium levels in males and females among the occupational Cr(Ⅵ) compounds exposure cohort was 2.77 and 1.79 μg/L, respectively. A turning point appeared in 6.00 μg/L chromium in whole blood of the exposure-response curve of whole blood chromium levels with lung function indicators and genetic toxicity indicators. For each unit increase in the natural logarithm-transformed whole blood chromium level, the forced expiratory volume in one second (FEV₁) decreased by 0.05 L, the FEV₁/forced-vital-capacity decreased by 0.67%, the peak expiratory flow decreased by 0.15 L/s, the maximal mid-expiratory flow decreased by 0.09 L/s, the MNF increased by 0.149‰, the urinary 8-OHdG increased by 0.090 μg/g, and the mtCN increased by 0.013. When the whole blood chromium level was >6.00 μg/L, there was a significant increase in urinary 8-OHdG, MNF, and mtCN (all P<0.01). Conclusion The level of whole blood chromium can be used as a biomarker for occupational exposure to soluble Cr(Ⅵ) compounds. The preliminary biological exposure limit is set at 6.00 μg/L for whole blood chromium in workers exposed to soluble Cr(Ⅵ) compounds.

ObjectiveTo establish a high performance liquid chromatography（HPLC） fingerprint of Yanghetang benchmark sample， and evaluate its quality with chemometric methods， so as to provide a reference for the quality control of this benchmark sample. MethodHPLC was used to establish the fingerprint of Yanghetang benchmark sample with ZORBAX SB-C₁₈ column（4.6 mm×250 mm， 5 μm）， the mobile phase was consisted of acetonitrile（A） -0.05% phosphoric acid aqueous solution （containing 0.05% triethylamine solution）（B） for gradient elution（0-5 min， 2%-3%A； 5-15 min， 3%-5%A； 15-65 min， 5%-30%A； 65-90 min， 30%-70%A）， the flow rate was 1.0 mL·min^-1， the column temperature was 35 ℃， and the detection wavelength was 210， 260 nm. Traditional Chinese Medicine（TCM） Chromatographic Fingerprint Similarity Evaluation System （2012 edition） combined with cluster analysis， principal component analysis（PCA） and partial least squares-discriminant analysis（PLS-DA） were used to evaluate the quality differences between different batches of Yanghetang benchmark samples， and to find the main chemical components responsible for the quality differences. ResultHPLC fingerprint of Yanghetang benchmark sample was established， 13 common peaks were identified and attributed to each common peak， including peaks 2 and 8 from Rehmanniae Radix Praeparata， peaks 10 and 11 from Cinnamomi Cortex， peaks 1， 3-6 from fried Sinapis Semen， peak 13 from Ephedrae Herba， and peaks 7， 9， 12 from Glycyrrhizae Radix et Rhizoma. Eight of them were identified by comparing with control substance， which were 5-hydroxymethylfurfural（peak 2）， sinapine thiocyanate（peak 4）， glycyrrhizin（peak 7）， verbascoside（peak 8）， cinnamic acid（peak 10）， cinnamaldehyde（peak 11）， glycyrrhizic acid（peak 12） and ephedrine hydrochloride（peak 13）. The similarities of the HPLC fingerprints of 15 batches of Yanghetang benchmark samples with the control fingerprint were all greater than 0.80. The three chemometric methods could classify the samples into two categories. Eight differential components were screened out， among which 5-hydroxymethylfurfural， sinapine thiocyanate， verbascoside and ephedrine hydrochloride were identified. ConclusionThe established fingerprint analysis method is accurate， stable and reproducible， which basically reflects the overall chemical composition of Yanghetang benchmark sample， and can provide a basis for establishment of quality standards for compound preparations of this famous classical formula.